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Sample records for visual performance feedback

  1. Influence of visual feedback on human task performance in ITER remote handling

    Energy Technology Data Exchange (ETDEWEB)

    Schropp, Gwendolijn Y.R., E-mail: g.schropp@heemskerk-innovative.nl [Utrecht University, Utrecht (Netherlands); Heemskerk Innovative Technology, Noordwijk (Netherlands); Heemskerk, Cock J.M. [Heemskerk Innovative Technology, Noordwijk (Netherlands); Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann [Helmholtz Institute-Utrecht University, Utrecht (Netherlands); Elzendoorn, Ben S.Q. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands); Bult, David [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The performance of human operators in an ITER-like test facility for remote handling. Black-Right-Pointing-Pointer Different sources of visual feedback influence how fast one can complete a maintenance task. Black-Right-Pointing-Pointer Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

  2. Influence of visual feedback on human task performance in ITER remote handling

    International Nuclear Information System (INIS)

    Schropp, Gwendolijn Y.R.; Heemskerk, Cock J.M.; Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann; Elzendoorn, Ben S.Q.; Bult, David

    2012-01-01

    Highlights: ► The performance of human operators in an ITER-like test facility for remote handling. ► Different sources of visual feedback influence how fast one can complete a maintenance task. ► Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

  3. Audio-visual feedback improves the BCI performance in the navigational control of a humanoid robot

    Directory of Open Access Journals (Sweden)

    Emmanuele eTidoni

    2014-06-01

    Full Text Available Advancement in brain computer interfaces (BCI technology allows people to actively interact in the world through surrogates. Controlling real humanoid robots using BCI as intuitively as we control our body represents a challenge for current research in robotics and neuroscience. In order to successfully interact with the environment the brain integrates multiple sensory cues to form a coherent representation of the world. Cognitive neuroscience studies demonstrate that multisensory integration may imply a gain with respect to a single modality and ultimately improve the overall sensorimotor performance. For example, reactivity to simultaneous visual and auditory stimuli may be higher than to the sum of the same stimuli delivered in isolation or in temporal sequence. Yet, knowledge about whether audio-visual integration may improve the control of a surrogate is meager. To explore this issue, we provided human footstep sounds as audio feedback to BCI users while controlling a humanoid robot. Participants were asked to steer their robot surrogate and perform a pick-and-place task through BCI-SSVEPs. We found that audio-visual synchrony between footsteps sound and actual humanoid’s walk reduces the time required for steering the robot. Thus, auditory feedback congruent with the humanoid actions may improve motor decisions of the BCI’s user and help in the feeling of control over it. Our results shed light on the possibility to increase robot’s control through the combination of multisensory feedback to a BCI user.

  4. Brain-actuated gait trainer with visual and proprioceptive feedback

    Science.gov (United States)

    Liu, Dong; Chen, Weihai; Lee, Kyuhwa; Chavarriaga, Ricardo; Bouri, Mohamed; Pei, Zhongcai; Millán, José del R.

    2017-10-01

    Objective. Brain-machine interfaces (BMIs) have been proposed in closed-loop applications for neuromodulation and neurorehabilitation. This study describes the impact of different feedback modalities on the performance of an EEG-based BMI that decodes motor imagery (MI) of leg flexion and extension. Approach. We executed experiments in a lower-limb gait trainer (the legoPress) where nine able-bodied subjects participated in three consecutive sessions based on a crossover design. A random forest classifier was trained from the offline session and tested online with visual and proprioceptive feedback, respectively. Post-hoc classification was conducted to assess the impact of feedback modalities and learning effect (an improvement over time) on the simulated trial-based performance. Finally, we performed feature analysis to investigate the discriminant power and brain pattern modulations across the subjects. Main results. (i) For real-time classification, the average accuracy was 62.33 +/- 4.95 % and 63.89 +/- 6.41 % for the two online sessions. The results were significantly higher than chance level, demonstrating the feasibility to distinguish between MI of leg extension and flexion. (ii) For post-hoc classification, the performance with proprioceptive feedback (69.45 +/- 9.95 %) was significantly better than with visual feedback (62.89 +/- 9.20 %), while there was no significant learning effect. (iii) We reported individual discriminate features and brain patterns associated to each feedback modality, which exhibited differences between the two modalities although no general conclusion can be drawn. Significance. The study reported a closed-loop brain-controlled gait trainer, as a proof of concept for neurorehabilitation devices. We reported the feasibility of decoding lower-limb movement in an intuitive and natural way. As far as we know, this is the first online study discussing the role of feedback modalities in lower-limb MI decoding. Our results suggest that

  5. Effect of visual feedback on brain activation during motor tasks: an FMRI study.

    Science.gov (United States)

    Noble, Jeremy W; Eng, Janice J; Boyd, Lara A

    2013-07-01

    This study examined the effect of visual feedback and force level on the neural mechanisms responsible for the performance of a motor task. We used a voxel-wise fMRI approach to determine the effect of visual feedback (with and without) during a grip force task at 35% and 70% of maximum voluntary contraction. Two areas (contralateral rostral premotor cortex and putamen) displayed an interaction between force and feedback conditions. When the main effect of feedback condition was analyzed, higher activation when visual feedback was available was found in 22 of the 24 active brain areas, while the two other regions (contralateral lingual gyrus and ipsilateral precuneus) showed greater levels of activity when no visual feedback was available. The results suggest that there is a potentially confounding influence of visual feedback on brain activation during a motor task, and for some regions, this is dependent on the level of force applied.

  6. Augmented visual feedback of movement performance to enhance walking recovery after stroke: study protocol for a pilot randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Thikey Heather

    2012-09-01

    Full Text Available Abstract Background Increasing evidence suggests that use of augmented visual feedback could be a useful approach to stroke rehabilitation. In current clinical practice, visual feedback of movement performance is often limited to the use of mirrors or video. However, neither approach is optimal since cognitive and self-image issues can distract or distress patients and their movement can be obscured by clothing or limited viewpoints. Three-dimensional motion capture has the potential to provide accurate kinematic data required for objective assessment and feedback in the clinical environment. However, such data are currently presented in numerical or graphical format, which is often impractical in a clinical setting. Our hypothesis is that presenting this kinematic data using bespoke visualisation software, which is tailored for gait rehabilitation after stroke, will provide a means whereby feedback of movement performance can be communicated in a more meaningful way to patients. This will result in increased patient understanding of their rehabilitation and will enable progress to be tracked in a more accessible way. Methods The hypothesis will be assessed using an exploratory (phase II randomised controlled trial. Stroke survivors eligible for this trial will be in the subacute stage of stroke and have impaired walking ability (Functional Ambulation Classification of 1 or more. Participants (n = 45 will be randomised into three groups to compare the use of the visualisation software during overground physical therapy gait training against an intensity-matched and attention-matched placebo group and a usual care control group. The primary outcome measure will be walking speed. Secondary measures will be Functional Ambulation Category, Timed Up and Go, Rivermead Visual Gait Assessment, Stroke Impact Scale-16 and spatiotemporal parameters associated with walking. Additional qualitative measures will be used to assess the participant

  7. Differential effects of visual feedback on subjective visual vertical accuracy and precision.

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    Daniel Bjasch

    Full Text Available The brain constructs an internal estimate of the gravitational vertical by integrating multiple sensory signals. In darkness, systematic head-roll dependent errors in verticality estimates, as measured by the subjective visual vertical (SVV, occur. We hypothesized that visual feedback after each trial results in increased accuracy, as physiological adjustment errors (A-/E-effect are likely based on central computational mechanisms and investigated whether such improvements were related to adaptational shifts of perceived vertical or to a higher cognitive strategy. We asked 12 healthy human subjects to adjust a luminous arrow to vertical in various head-roll positions (0 to 120deg right-ear down, 15deg steps. After each adjustment visual feedback was provided (lights on, display of previous adjustment and of an earth-vertical cross. Control trials consisted of SVV adjustments without feedback. At head-roll angles with the largest A-effect (90, 105, and 120deg, errors were reduced significantly (p0.05 influenced. In seven subjects an additional session with two consecutive blocks (first with, then without visual feedback was completed at 90, 105 and 120deg head-roll. In these positions the error-reduction by the previous visual feedback block remained significant over the consecutive 18-24 min (post-feedback block, i.e., was still significantly (p<0.002 different from the control trials. Eleven out of 12 subjects reported having consciously added a bias to their perceived vertical based on visual feedback in order to minimize errors. We conclude that improvements of SVV accuracy by visual feedback, which remained effective after removal of feedback for ≥18 min, rather resulted from a cognitive strategy than by adapting the internal estimate of the gravitational vertical. The mechanisms behind the SVV therefore, remained stable, which is also supported by the fact that SVV precision - depending mostly on otolith input - was not affected by visual

  8. Learning without knowing: subliminal visual feedback facilitates ballistic motor learning

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Leukel, Christian; Nielsen, Jens Bo

    by subconscious (subliminal) augmented visual feedback on motor performance. To test this, 45 subjects participated in the experiment, which involved learning of a ballistic task. The task was to execute simple ankle plantar flexion movements as quickly as possible within 200 ms and to continuously improve...... by the learner, indeed facilitated ballistic motor learning. This effect likely relates to multiple (conscious versus unconscious) processing of visual feedback and to the specific neural circuitries involved in optimization of ballistic motor performance.......). It is a well- described phenomenon that we may respond to features of our surroundings without being aware of them. It is also a well-known principle, that learning is reinforced by augmented feedback on motor performance. In the present experiment we hypothesized that motor learning may be facilitated...

  9. Can explicit visual feedback of postural sway efface the effects of sensory manipulations on mediolateral balance performance?

    OpenAIRE

    Cofre Lizama, L.E.; Pijnappels, M.A.G.M.; Reeves, N.P.; Verschueren, S.M.; van Dieen, J.H.

    2016-01-01

    Explicit visual feedback on postural sway is often used in balance assessment and training. However, up-weighting of visual information may mask impairments of other sensory systems. We therefore aimed to determine whether the effects of somatosensory, vestibular, and proprioceptive manipulations on mediolateral balance are reduced by explicit visual feedback on mediolateral sway of the body center of mass and by the presence of visual information. We manipulated sensory inputs of the somatos...

  10. The effects of spatially displaced visual feedback on remote manipulator performance

    Science.gov (United States)

    Smith, Randy L.; Stuart, Mark A.

    1993-01-01

    The results of this evaluation have important implications for the arrangement of remote manipulation worksites and the design of workstations for telerobot operations. This study clearly illustrates the deleterious effects that can accompany the performance of remote manipulator tasks when viewing conditions are less than optimal. Future evaluations should emphasize telerobot camera locations and the use of image/graphical enhancement techniques in an attempt to lessen the adverse effects of displaced visual feedback. An important finding in this evaluation is the extent to which results from previously performed direct manipulation studies can be generalized to remote manipulation studies. Even though the results obtained were very similar to those of the direct manipulation evaluations, there were differences as well. This evaluation has demonstrated that generalizations to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.

  11. Voluntarily controlled but not merely observed visual feedback affects postural sway

    Science.gov (United States)

    Asai, Tomohisa; Hiromitsu, Kentaro; Imamizu, Hiroshi

    2018-01-01

    Online stabilization of human standing posture utilizes multisensory afferences (e.g., vision). Whereas visual feedback of spontaneous postural sway can stabilize postural control especially when observers concentrate on their body and intend to minimize postural sway, the effect of intentional control of visual feedback on postural sway itself remains unclear. This study assessed quiet standing posture in healthy adults voluntarily controlling or merely observing visual feedback. The visual feedback (moving square) had either low or high gain and was either horizontally flipped or not. Participants in the voluntary-control group were instructed to minimize their postural sway while voluntarily controlling visual feedback, whereas those in the observation group were instructed to minimize their postural sway while merely observing visual feedback. As a result, magnified and flipped visual feedback increased postural sway only in the voluntary-control group. Furthermore, regardless of the instructions and feedback manipulations, the experienced sense of control over visual feedback positively correlated with the magnitude of postural sway. We suggest that voluntarily controlled, but not merely observed, visual feedback is incorporated into the feedback control system for posture and begins to affect postural sway. PMID:29682421

  12. Feature-Specific Organization of Feedback Pathways in Mouse Visual Cortex.

    Science.gov (United States)

    Huh, Carey Y L; Peach, John P; Bennett, Corbett; Vega, Roxana M; Hestrin, Shaul

    2018-01-08

    Higher and lower cortical areas in the visual hierarchy are reciprocally connected [1]. Although much is known about how feedforward pathways shape receptive field properties of visual neurons, relatively little is known about the role of feedback pathways in visual processing. Feedback pathways are thought to carry top-down signals, including information about context (e.g., figure-ground segmentation and surround suppression) [2-5], and feedback has been demonstrated to sharpen orientation tuning of neurons in the primary visual cortex (V1) [6, 7]. However, the response characteristics of feedback neurons themselves and how feedback shapes V1 neurons' tuning for other features, such as spatial frequency (SF), remain largely unknown. Here, using a retrograde virus, targeted electrophysiological recordings, and optogenetic manipulations, we show that putatively feedback neurons in layer 5 (hereafter "L5 feedback") in higher visual areas, AL (anterolateral area) and PM (posteromedial area), display distinct visual properties in awake head-fixed mice. AL L5 feedback neurons prefer significantly lower SF (mean: 0.04 cycles per degree [cpd]) compared to PM L5 feedback neurons (0.15 cpd). Importantly, silencing AL L5 feedback reduced visual responses of V1 neurons preferring low SF (mean change in firing rate: -8.0%), whereas silencing PM L5 feedback suppressed responses of high-SF-preferring V1 neurons (-20.4%). These findings suggest that feedback connections from higher visual areas convey distinctly tuned visual inputs to V1 that serve to boost V1 neurons' responses to SF. Such like-to-like functional organization may represent an important feature of feedback pathways in sensory systems and in the nervous system in general. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The Role of Visual Feedback on Power Output During Intermittent Wingate Testing in Ice Hockey Players

    Directory of Open Access Journals (Sweden)

    Petr Stastny

    2018-04-01

    Full Text Available Background: Visual feedback may help elicit peak performance during different types of strength and power testing, but its effect during the anaerobic Wingate test is unexplored. Therefore, the purpose of this study was to determine the effect of visual feedback on power output during a hockey-specific intermittent Wingate test (AnWT6x6 consisting of 6 stages of 6 s intervals with a 1:1 work-to-rest ratio. Methods: Thirty elite college-aged hockey players performed the AnWT6x6 with either constant (n = 15 visual feedback during all 6 stages (CVF or restricted (n = 15 visual feedback (RVF where feedback was shown only during the 2nd through 5th stages. Results: In the first stage, there were moderate-to-large effect sizes for absolute peak power (PP output and PP relative to body mass and PP relative to fat-free mass. However, the remaining stages (2–6 displayed small or negligible effects. Conclusions: These data indicate that visual feedback may play a role in optimizing power output in a non-fatigued state (1st stage, but likely does not play a role in the presence of extreme neuromuscular fatigue (6th stage during Wingate testing. To achieve the highest peak power, coaches and researchers could provide visual feedback during Wingate testing, as it may positively influence performance in the early stages of testing, but does not result in residual fatigue or negatively affect performance during subsequent stages.

  14. Sonification and haptic feedback in addition to visual feedback enhances complex motor task learning.

    Science.gov (United States)

    Sigrist, Roland; Rauter, Georg; Marchal-Crespo, Laura; Riener, Robert; Wolf, Peter

    2015-03-01

    Concurrent augmented feedback has been shown to be less effective for learning simple motor tasks than for complex tasks. However, as mostly artificial tasks have been investigated, transfer of results to tasks in sports and rehabilitation remains unknown. Therefore, in this study, the effect of different concurrent feedback was evaluated in trunk-arm rowing. It was then investigated whether multimodal audiovisual and visuohaptic feedback are more effective for learning than visual feedback only. Naïve subjects (N = 24) trained in three groups on a highly realistic virtual reality-based rowing simulator. In the visual feedback group, the subject's oar was superimposed to the target oar, which continuously became more transparent when the deviation between the oars decreased. Moreover, a trace of the subject's trajectory emerged if deviations exceeded a threshold. The audiovisual feedback group trained with oar movement sonification in addition to visual feedback to facilitate learning of the velocity profile. In the visuohaptic group, the oar movement was inhibited by path deviation-dependent braking forces to enhance learning of spatial aspects. All groups significantly decreased the spatial error (tendency in visual group) and velocity error from baseline to the retention tests. Audiovisual feedback fostered learning of the velocity profile significantly more than visuohaptic feedback. The study revealed that well-designed concurrent feedback fosters complex task learning, especially if the advantages of different modalities are exploited. Further studies should analyze the impact of within-feedback design parameters and the transferability of the results to other tasks in sports and rehabilitation.

  15. Measuring voluntary quadriceps activation: Effect of visual feedback and stimulus delivery.

    Science.gov (United States)

    Luc, Brittney A; Harkey, Matthew H; Arguelles, Gabrielle D; Blackburn, J Troy; Ryan, Eric D; Pietrosimone, Brian

    2016-02-01

    Quadriceps voluntary activation, assessed via the superimposed burst technique, has been extensively studied in a variety of populations as a measure of quadriceps function. However, a variety of stimulus delivery techniques have been employed, which may influence the level of voluntary activation as calculated via the central activation ratio (CAR). The purpose was to determine the effect of visual feedback, stimulus delivery, and perceived discomfort on maximal voluntary isometric contraction (MVIC) peak torque and the CAR. Quadriceps CAR was assessed in 14 individuals on two days using three stimulus delivery methods; (1) manual without visual feedback, (2) manual with visual feedback, and (3) automated with visual feedback. MVIC peak torque and the CAR were not different between the automated with visual feedback (MVIC=3.25, SE=0.14Nm/kg; CAR=88.63, SE=1.75%) and manual with visual feedback (MVIC=3.26, SE=0.13Nm/kg, P=0.859; CAR=89.06, SE=1.70%, P=0.39) stimulus delivery methods. MVIC (2.99, SE=0.12Nm/kg) and CAR (85.32, SE=2.10%) were significantly lower using manual without visual feedback compared to manual with visual feedback and automated with visual feedback (CAR P<0.001; MVIC P<0.001). Perceived discomfort was lower in the second session (P<0.05). Utilizing visual feedback ensures participant MVIC, and may provide a more accurate assessment of quadriceps voluntary activation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Using visual feedback distortion to alter coordinated pinching patterns for robotic rehabilitation

    Directory of Open Access Journals (Sweden)

    Brewer Bambi R

    2007-05-01

    Full Text Available Abstract Background It is common for individuals with chronic disabilities to continue using the compensatory movement coordination due to entrenched habits, increased perception of task difficulty, or personality variables such as low self-efficacy or a fear of failure. Following our previous work using feedback distortion in a virtual rehabilitation environment to increase strength and range of motion, we address the use of visual feedback distortion environment to alter movement coordination patterns. Methods Fifty-one able-bodied subjects participated in the study. During the experiment, each subject learned to move their index finger and thumb in a particular target pattern while receiving visual feedback. Visual distortion was implemented as a magnification of the error between the thumb and/or index finger position and the desired position. The error reduction profile and the effect of distortion were analyzed by comparing the mean total absolute error and a normalized error that measured performance improvement for each subject as a proportion of the baseline error. Results The results of the study showed that (1 different coordination pattern could be trained with visual feedback and have the new pattern transferred to trials without visual feedback, (2 distorting individual finger at a time allowed different error reduction profile from the controls, and (3 overall learning was not sped up by distorting individual fingers. Conclusion It is important that robotic rehabilitation incorporates multi-limb or finger coordination tasks that are important for activities of daily life in the near future. This study marks the first investigation on multi-finger coordination tasks under visual feedback manipulation.

  17. Effects of continuous visual feedback during sitting balance training in chronic stroke survivors.

    Science.gov (United States)

    Pellegrino, Laura; Giannoni, Psiche; Marinelli, Lucio; Casadio, Maura

    2017-10-16

    Postural control deficits are common in stroke survivors and often the rehabilitation programs include balance training based on visual feedback to improve the control of body position or of the voluntary shift of body weight in space. In the present work, a group of chronic stroke survivors, while sitting on a force plate, exercised the ability to control their Center of Pressure with a training based on continuous visual feedback. The goal of this study was to test if and to what extent chronic stroke survivors were able to learn the task and transfer the learned ability to a condition without visual feedback and to directions and displacement amplitudes different from those experienced during training. Eleven chronic stroke survivors (5 Male - 6 Female, age: 59.72 ± 12.84 years) participated in this study. Subjects were seated on a stool positioned on top of a custom-built force platform. Their Center of Pressure positions were mapped to the coordinate of a cursor on a computer monitor. During training, the cursor position was always displayed and the subjects were to reach targets by shifting their Center of Pressure by moving their trunk. Pre and post-training subjects were required to reach without visual feedback of the cursor the training targets as well as other targets positioned in different directions and displacement amplitudes. During training, most stroke survivors were able to perform the required task and to improve their performance in terms of duration, smoothness, and movement extent, although not in terms of movement direction. However, when we removed the visual feedback, most of them had no improvement with respect to their pre-training performance. This study suggests that postural training based exclusively on continuous visual feedback can provide limited benefits for stroke survivors, if administered alone. However, the positive gains observed during training justify the integration of this technology-based protocol in a well

  18. The effect of haptic guidance and visual feedback on learning a complex tennis task.

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    Marchal-Crespo, Laura; van Raai, Mark; Rauter, Georg; Wolf, Peter; Riener, Robert

    2013-11-01

    While haptic guidance can improve ongoing performance of a motor task, several studies have found that it ultimately impairs motor learning. However, some recent studies suggest that the haptic demonstration of optimal timing, rather than movement magnitude, enhances learning in subjects trained with haptic guidance. Timing of an action plays a crucial role in the proper accomplishment of many motor skills, such as hitting a moving object (discrete timing task) or learning a velocity profile (time-critical tracking task). The aim of the present study is to evaluate which feedback conditions-visual or haptic guidance-optimize learning of the discrete and continuous elements of a timing task. The experiment consisted in performing a fast tennis forehand stroke in a virtual environment. A tendon-based parallel robot connected to the end of a racket was used to apply haptic guidance during training. In two different experiments, we evaluated which feedback condition was more adequate for learning: (1) a time-dependent discrete task-learning to start a tennis stroke and (2) a tracking task-learning to follow a velocity profile. The effect that the task difficulty and subject's initial skill level have on the selection of the optimal training condition was further evaluated. Results showed that the training condition that maximizes learning of the discrete time-dependent motor task depends on the subjects' initial skill level. Haptic guidance was especially suitable for less-skilled subjects and in especially difficult discrete tasks, while visual feedback seems to benefit more skilled subjects. Additionally, haptic guidance seemed to promote learning in a time-critical tracking task, while visual feedback tended to deteriorate the performance independently of the task difficulty and subjects' initial skill level. Haptic guidance outperformed visual feedback, although additional studies are needed to further analyze the effect of other types of feedback visualization on

  19. The Effect of Concurrent Visual Feedback on Controlling Swimming Speed

    Directory of Open Access Journals (Sweden)

    Szczepan Stefan

    2016-03-01

    Full Text Available Introduction. Developing the ability to control the speed of swimming is an important part of swimming training. Maintaining a defined constant speed makes it possible for the athlete to swim economically at a low physiological cost. The aim of this study was to determine the effect of concurrent visual feedback transmitted by the Leader device on the control of swimming speed in a single exercise test. Material and methods. The study involved a group of expert swimmers (n = 20. Prior to the experiment, the race time for the 100 m distance was determined for each of the participants. In the experiment, the participants swam the distance of 100 m without feedback and with visual feedback. In both variants, the task of the participants was to swim the test distance in a time as close as possible to the time designated prior to the experiment. In the first version of the experiment (without feedback, the participants swam the test distance without receiving real-time feedback on their swimming speed. In the second version (with visual feedback, the participants followed a beam of light moving across the bottom of the swimming pool, generated by the Leader device. Results. During swimming with visual feedback, the 100 m race time was significantly closer to the time designated. The difference between the pre-determined time and the time obtained was significantly statistically lower during swimming with visual feedback (p = 0.00002. Conclusions. Concurrently transmitting visual feedback to athletes improves their control of swimming speed. The Leader device has proven useful in controlling swimming speed.

  20. Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke.

    Science.gov (United States)

    Secoli, Riccardo; Milot, Marie-Helene; Rosati, Giulio; Reinkensmeyer, David J

    2011-04-23

    Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm, suggesting that the increased demands associated

  1. Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke

    Directory of Open Access Journals (Sweden)

    Reinkensmeyer David J

    2011-04-01

    Full Text Available Abstract Background Practicing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task. Methods Fourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error. Results Participants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke. Conclusions Visual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for

  2. [Nursing Experience of Using Mirror Visual Feedback for a Schizophrenia Patient With Visual Hallucinations].

    Science.gov (United States)

    Lan, Shu-Ling; Chen, Yu-Chi; Chang, Hsiu-Ju

    2018-06-01

    The aim of this paper was to describe the nursing application of mirror visual feedback in a patient suffering from long-term visual hallucinations. The intervention period was from May 15th to October 19th, 2015. Using the five facets of psychiatric nursing assessment, several health problems were observed, including disturbed sensory perceptions (prominent visual hallucinations) and poor self-care (e.g. limited abilities to self-bathe and put on clothing). Furthermore, "caregiver role strain" due to the related intense care burden was noted. After building up a therapeutic interpersonal relationship, the technique of brain plasticity and mirror visual feedback were performed using multiple nursing care methods in order to help the patient suppress her visual hallucinations by enhancing a different visual stimulus. We also taught her how to cope with visual hallucinations in a proper manner. The frequency and content of visual hallucinations were recorded to evaluate the effects of management. The therapeutic plan was formulated together with the patient in order to boost her self-confidence, and a behavior contract was implemented in order to improve her personal hygiene. In addition, psychoeducation on disease-related topics was provided to the patient's family, and they were encouraged to attend relevant therapeutic activities. As a result, her family became less passive and negative and more engaged in and positive about her future. The crisis of "caregiver role strain" was successfully resolved. The current experience is hoped to serve as a model for enhancing communication and cooperation between family and staff in similar medical settings.

  3. Persuasive performance feedback: the effect of framing on self-efficacy.

    Science.gov (United States)

    Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A

    2013-01-01

    Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user's current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual's self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual's performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors.

  4. Persuasive Performance Feedback: The Effect of Framing on Self-Efficacy

    Science.gov (United States)

    Choe, Eun Kyoung; Lee, Bongshin; Munson, Sean; Pratt, Wanda; Kientz, Julie A.

    2013-01-01

    Self-monitoring technologies have proliferated in recent years as they offer excellent potential for promoting healthy behaviors. Although these technologies have varied ways of providing real-time feedback on a user’s current progress, we have a dearth of knowledge of the framing effects on the performance feedback these tools provide. With an aim to create influential, persuasive performance feedback that will nudge people toward healthy behaviors, we conducted an online experiment to investigate the effect of framing on an individual’s self-efficacy. We identified 3 different types of framing that can be applicable in presenting performance feedback: (1) the valence of performance (remaining vs. achieved framing), (2) presentation type (text-only vs. text with visual), and (3) data unit (raw vs. percentage). Results show that the achieved framing could lead to an increased perception of individual’s performance capabilities. This work provides empirical guidance for creating persuasive performance feedback, thereby helping people designing self-monitoring technologies to promote healthy behaviors. PMID:24551378

  5. Can explicit visual feedback of postural sway efface the effects of sensory manipulations on mediolateral balance performance?

    NARCIS (Netherlands)

    Cofre Lizama, L.E.; Pijnappels, M.A.G.M.; Reeves, N.P.; Verschueren, S.M.; van Dieen, J.H.

    2016-01-01

    Explicit visual feedback on postural sway is often used in balance assessment and training. However, up-weighting of visual information may mask impairments of other sensory systems. We therefore aimed to determine whether the effects of somatosensory, vestibular, and proprioceptive manipulations on

  6. Active training and driving-specific feedback improve older drivers' visual search prior to lane changes.

    Science.gov (United States)

    Lavallière, Martin; Simoneau, Martin; Tremblay, Mathieu; Laurendeau, Denis; Teasdale, Normand

    2012-03-02

    Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses) do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group). Their results were compared to a Control group (12 older drivers) who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot). In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes). These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

  7. The Effect of Visual Feedback on Writing Size in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Adriaan R. E. Potgieser

    2015-01-01

    Full Text Available Parkinson’s disease (PD leads to impairment in multiple cognitive domains. Micrographia is a relatively early PD sign of visuomotor dysfunction, characterized by a global reduction in writing size and a decrement in size during writing. Here we aimed to investigate the effect of withdrawal of visual feedback on writing size in patients with PD. Twenty-five patients with non-tremor-dominant PD without cognitive dysfunction and twenty-five age-matched controls had to write a standard sentence with and without visual feedback. We assessed the effect of withdrawal of visual feedback by measuring vertical word size (i, horizontal length of the sentence (ii, and the summed horizontal word length without interspacing (iii, comparing patients with controls. In both patients and controls, writing was significantly larger without visual feedback. This enlargement did not significantly differ between the groups. Smaller handwriting significantly correlated with increased disease severity. Contrary to previous observations that withdrawal of visual feedback caused increased writing size in specifically PD, we did not find differences between patients and controls. Both groups wrote larger without visual feedback, which adds insight in general neuronal mechanisms underlying the balance between feed-forward and feedback in visuomotor control, mechanisms that also hold for grasping movements.

  8. Unipedal balance in healthy adults: effect of visual environments yielding decreased lateral velocity feedback.

    Science.gov (United States)

    Deyer, T W; Ashton-Miller, J A

    1999-09-01

    To test the (null) hypotheses that the reliability of unipedal balance is unaffected by the attenuation of visual velocity feedback and that, relative to baseline performance, deterioration of balance success rates from attenuated visual velocity feedback will not differ between groups of young men and older women, and the presence (or absence) of a vertical foreground object will not affect balance success rates. Single blind, single case study. University research laboratory. Two volunteer samples: 26 healthy young men (mean age, 20.0yrs; SD, 1.6); 23 healthy older women (mean age, 64.9 yrs; SD, 7.8). Normalized success rates in unipedal balance task. Subjects were asked to transfer to and maintain unipedal stance for 5 seconds in a task near the limit of their balance capabilities. Subjects completed 64 trials: 54 trials of three experimental visual scenes in blocked randomized sequences of 18 trials and 10 trials in a normal visual environment. The experimental scenes included two that provided strong velocity/weak position feedback, one of which had a vertical foreground object (SVWP+) and one without (SVWP-), and one scene providing weak velocity/strong position (WVSP) feedback. Subjects' success rates in the experimental environments were normalized by the success rate in the normal environment in order to allow comparisons between subjects using a mixed model repeated measures analysis of variance. The normalized success rate was significantly greater in SVWP+ than in WVSP (p = .0001) and SVWP- (p = .013). Visual feedback significantly affected the normalized unipedal balance success rates (p = .001); neither the group effect nor the group X visual environment interaction was significant (p = .9362 and p = .5634, respectively). Normalized success rates did not differ significantly between the young men and older women in any visual environment. Near the limit of the young men's or older women's balance capability, the reliability of transfer to unipedal

  9. Effects of Visual Feedback Distortion on Gait Adaptation: Comparison of Implicit Visual Distortion Versus Conscious Modulation on Retention of Motor Learning.

    Science.gov (United States)

    Kim, Seung-Jae; Ogilvie, Mitchell; Shimabukuro, Nathan; Stewart, Trevor; Shin, Joon-Ho

    2015-09-01

    Visual feedback can be used during gait rehabilitation to improve the efficacy of training. We presented a paradigm called visual feedback distortion; the visual representation of step length was manipulated during treadmill walking. Our prior work demonstrated that an implicit distortion of visual feedback of step length entails an unintentional adaptive process in the subjects' spatial gait pattern. Here, we investigated whether the implicit visual feedback distortion, versus conscious correction, promotes efficient locomotor adaptation that relates to greater retention of a task. Thirteen healthy subjects were studied under two conditions: (1) we implicitly distorted the visual representation of their gait symmetry over 14 min, and (2) with help of visual feedback, subjects were told to walk on the treadmill with the intent of attaining the gait asymmetry observed during the first implicit trial. After adaptation, the visual feedback was removed while subjects continued walking normally. Over this 6-min period, retention of preserved asymmetric pattern was assessed. We found that there was a greater retention rate during the implicit distortion trial than that of the visually guided conscious modulation trial. This study highlights the important role of implicit learning in the context of gait rehabilitation by demonstrating that training with implicit visual feedback distortion may produce longer lasting effects. This suggests that using visual feedback distortion could improve the effectiveness of treadmill rehabilitation processes by influencing the retention of motor skills.

  10. Active training and driving-specific feedback improve older drivers' visual search prior to lane changes

    Directory of Open Access Journals (Sweden)

    Lavallière Martin

    2012-03-01

    Full Text Available Abstract Background Driving retraining classes may offer an opportunity to attenuate some effects of aging that may alter driving skills. Unfortunately, there is evidence that classroom programs (driving refresher courses do not improve the driving performance of older drivers. The aim of the current study was to evaluate if simulator training sessions with video-based feedback can modify visual search behaviors of older drivers while changing lanes in urban driving. Methods In order to evaluate the effectiveness of the video-based feedback training, 10 older drivers who received a driving refresher course and feedback about their driving performance were tested with an on-road standardized evaluation before and after participating to a simulator training program (Feedback group. Their results were compared to a Control group (12 older drivers who received the same refresher course and in-simulator active practice as the Feedback group without receiving driving-specific feedback. Results After attending the training program, the Control group showed no increase in the frequency of the visual inspection of three regions of interests (rear view and left side mirrors, and blind spot. In contrast, for the Feedback group, combining active training and driving-specific feedbacks increased the frequency of blind spot inspection by 100% (32.3 to 64.9% of verification before changing lanes. Conclusions These results suggest that simulator training combined with driving-specific feedbacks helped older drivers to improve their visual inspection strategies, and that in-simulator training transferred positively to on-road driving. In order to be effective, it is claimed that driving programs should include active practice sessions with driving-specific feedbacks. Simulators offer a unique environment for developing such programs adapted to older drivers' needs.

  11. Peripheral visual performance enhancement by neurofeedback training.

    Science.gov (United States)

    Nan, Wenya; Wan, Feng; Lou, Chin Ian; Vai, Mang I; Rosa, Agostinho

    2013-12-01

    Peripheral visual performance is an important ability for everyone, and a positive inter-individual correlation is found between the peripheral visual performance and the alpha amplitude during the performance test. This study investigated the effect of alpha neurofeedback training on the peripheral visual performance. A neurofeedback group of 13 subjects finished 20 sessions of alpha enhancement feedback within 20 days. The peripheral visual performance was assessed by a new dynamic peripheral visual test on the first and last training day. The results revealed that the neurofeedback group showed significant enhancement of the peripheral visual performance as well as the relative alpha amplitude during the peripheral visual test. It was not the case in the non-neurofeedback control group, which performed the tests within the same time frame as the neurofeedback group but without any training sessions. These findings suggest that alpha neurofeedback training was effective in improving peripheral visual performance. To the best of our knowledge, this is the first study to show evidence for performance improvement in peripheral vision via alpha neurofeedback training.

  12. Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation.

    Science.gov (United States)

    Tapia, Evelina; Beck, Diane M

    2014-01-01

    A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness.

  13. Self-Produced Tickle Sensation by Manipulating Visual Feedback

    Directory of Open Access Journals (Sweden)

    Hiroyuki Iizuka

    2011-10-01

    Full Text Available The aim of the present paper was to clarify how the distinction of self- (sense of agency, SOA and other-produced behavior can be synthesized and recognized in multisensory integration as our cognitive processes. To address this issue, we used tickling paradigm that it is hard for us to tickle ourselves. Previous studies show that tickle sensation by their own motion increases if more delay is given between self-motion of tickling and tactile stimulation (Blakemore et al. 1998, 1999. We introduced visual feedbacks to the tickling experiments. In our hypothesis, integration of vision, proprioception, and motor commands forms the SOA and disintegration causes the breakdown the SOA, which causes the feeling of others, producing tickling sensation even by tickling oneself. We used video-see-through HMD to suddenly delay the real-time images of their hand tickling motions. The tickle sensation was measured by subjective response in the following conditions; 1 tickling oneself without any visual modulation, 2 tickled by others, 3 tickling oneself with visual feedback manipulation. The statistical analysis of ranked evaluation of tickle sensations showed that the delay of visual feedback causes the increase of tickle sensation. The SOA was discussed with Blakemore's and our results.

  14. Peripheral visual feedback: a powerful means of supporting effective attention allocation in event-driven, data-rich environments.

    Science.gov (United States)

    Nikolic, M I; Sarter, N B

    2001-01-01

    Breakdowns in human-automation coordination in data-rich, event-driven domains such as aviation can be explained in part by a mismatch between the high degree of autonomy yet low observability of modern technology. To some extent, the latter is the result of an increasing reliance in feedback design on foveal vision--an approach that fails to support pilots in tracking system-induced changes and events in parallel with performing concurrent flight-related tasks. One possible solution to the problem is the distribution of tasks and information across sensory modalities and processing channels. A simulator study is presented that compared the effectiveness of current foveal feedback and two implementations of peripheral visual feedback for keeping pilots informed about uncommanded changes in the status of an automated cockpit system. Both peripheral visual displays resulted in higher detection rates and faster response times, without interfering with the performance of concurrent visual tasks any more than does currently available automation feedback. Potential applications include improved display designs that support effective attention allocation in a variety of complex dynamic environments, such as aviation, process control, and medicine.

  15. Isometric force exaggeration in simulated weightlessness by water immersion: role of visual feedback.

    Science.gov (United States)

    Dalecki, Marc; Bock, Otmar

    2014-06-01

    Previous studies reported that humans produce exaggerated isometric forces (20-50%) in microgravity, hypergravity, and under water. Subjects were not provided with visual feedback and exaggerations were attributed to proprioceptive deficits. The few studies that provided visual feedback in micro- and hypergravity found no deficits. The present work was undertaken to find out whether visual feedback can reduce or eliminate isometric force exaggerations during shallow water immersion, a working environment for astronauts and divers. There were 48 subjects who had to produce isometric forces of 15 N with a joystick; targets were presented via screen. Procedures were similar to earlier studies, but provided visual feedback. Subjects were tested 16.4 ft (5 m) under water (WET) and on dry land (DRY). Response accuracy was calculated with landmarks such as initial and peak force magnitude, and response timing. Initial force and response timing were equal in WET compared to DRY. A small but significant force exaggeration (+5%) remained for peak force in WET that was limited to directions toward the trunk. Force exaggeration under water is largely compensated, but not completely eliminated by visual feedback. As in earlier studies without visual feedback, force exaggeration manifested during later but not early response parts, speaking for impaired proprioceptive feedback rather than for erroneous central motor planning. Since in contrast to micro/hypergravity, visual feedback did not sufficiently abolish force deficits under water, proprioceptive information seems to be weighted differently in micro/hypergravity and shallow water immersion, probably because only the latter environment produces increased ambient pressure, which is known to induce neuronal changes.

  16. Visual feedback training using WII Fit improves balance in Parkinson's disease.

    Science.gov (United States)

    Zalecki, Tomasz; Gorecka-Mazur, Agnieszka; Pietraszko, Wojciech; Surowka, Artur D; Novak, Pawel; Moskala, Marek; Krygowska-Wajs, Anna

    2013-01-01

    Postural instability including imbalance is the most disabling long term problem in Parkinson's disease (PD) that does not respond to pharmacotherapy. This study aimed at investigating the effectiveness of a novel visual-feedback training method, using Wii Fit balance board in improving balance in patients with PD. Twenty four patients with moderate PD were included in the study which comprised of a 6-week home-based balance training program using Nintendo Wii Fit and balance board. The PD patients significantly improved their results in Berg Balance Scale, Tinnet's Performance-Oriented Mobility Assessment, Timed Up-and-Go, Sit-to-stand test, 10-Meter Walk test and Activities-specific Balance Confidence scale at the end of the programme. This study suggests that visual feedback training using Wii-Fit with balance board could improve dynamic and functional balance as well as motor disability in PD patients.

  17. The absence or temporal offset of visual feedback does not influence adaptation to novel movement dynamics.

    Science.gov (United States)

    McKenna, Erin; Bray, Laurence C Jayet; Zhou, Weiwei; Joiner, Wilsaan M

    2017-10-01

    Delays in transmitting and processing sensory information require correctly associating delayed feedback to issued motor commands for accurate error compensation. The flexibility of this alignment between motor signals and feedback has been demonstrated for movement recalibration to visual manipulations, but the alignment dependence for adapting movement dynamics is largely unknown. Here we examined the effect of visual feedback manipulations on force-field adaptation. Three subject groups used a manipulandum while experiencing a lag in the corresponding cursor motion (0, 75, or 150 ms). When the offset was applied at the start of the session (continuous condition), adaptation was not significantly different between groups. However, these similarities may be due to acclimation to the offset before motor adaptation. We tested additional subjects who experienced the same delays concurrent with the introduction of the perturbation (abrupt condition). In this case adaptation was statistically indistinguishable from the continuous condition, indicating that acclimation to feedback delay was not a factor. In addition, end-point errors were not significantly different across the delay or onset conditions, but end-point correction (e.g., deceleration duration) was influenced by the temporal offset. As an additional control, we tested a group of subjects who performed without visual feedback and found comparable movement adaptation results. These results suggest that visual feedback manipulation (absence or temporal misalignment) does not affect adaptation to novel dynamics, independent of both acclimation and perceptual awareness. These findings could have implications for modeling how the motor system adjusts to errors despite concurrent delays in sensory feedback information. NEW & NOTEWORTHY A temporal offset between movement and distorted visual feedback (e.g., visuomotor rotation) influences the subsequent motor recalibration, but the effects of this offset for

  18. Three Principles for the Design of Energy Feedback Visualizations

    DEFF Research Database (Denmark)

    Brewer, Robert S.; Xu, Yongwen; Lee, George E.

    2013-01-01

    , online educational activities, and real-world activities such as workshops and excursions. We describe our experiences developing energy feedback visualizations in the Kukui Cup based on in-lab evaluations and field studies in college residence halls. We learned that energy feedback systems should...

  19. Reduction of the elevator illusion from continued hypergravity exposure and visual error-corrective feedback

    Science.gov (United States)

    Welch, R. B.; Cohen, M. M.; DeRoshia, C. W.

    1996-01-01

    Ten subjects served as their own controls in two conditions of continuous, centrifugally produced hypergravity (+2 Gz) and a 1-G control condition. Before and after exposure, open-loop measures were obtained of (1) motor control, (2) visual localization, and (3) hand-eye coordination. During exposure in the visual feedback/hypergravity condition, subjects received terminal visual error-corrective feedback from their target pointing, and in the no-visual feedback/hypergravity condition they pointed open loop. As expected, the motor control measures for both experimental conditions revealed very short lived underreaching (the muscle-loading effect) at the outset of hypergravity and an equally transient negative aftereffect on returning to 1 G. The substantial (approximately 17 degrees) initial elevator illusion experienced in both hypergravity conditions declined over the course of the exposure period, whether or not visual feedback was provided. This effect was tentatively attributed to habituation of the otoliths. Visual feedback produced a smaller additional decrement and a postexposure negative after-effect, possible evidence for visual recalibration. Surprisingly, the target-pointing error made during hypergravity in the no-visual-feedback condition was substantially less than that predicted by subjects' elevator illusion. This finding calls into question the neural outflow model as a complete explanation of this illusion.

  20. Technology-Assisted Rehabilitation of Writing Skills in Parkinson’s Disease: Visual Cueing versus Intelligent Feedback

    Directory of Open Access Journals (Sweden)

    Evelien Nackaerts

    2017-01-01

    Full Text Available Recent research showed that visual cueing can have both beneficial and detrimental effects on handwriting of patients with Parkinson’s disease (PD and healthy controls depending on the circumstances. Hence, using other sensory modalities to deliver cueing or feedback may be a valuable alternative. Therefore, the current study compared the effects of short-term training with either continuous visual cues or intermittent intelligent verbal feedback. Ten PD patients and nine healthy controls were randomly assigned to one of these training modes. To assess transfer of learning, writing performance was assessed in the absence of cueing and feedback on both trained and untrained writing sequences. The feedback pen and a touch-sensitive writing tablet were used for testing. Both training types resulted in improved writing amplitudes for the trained and untrained sequences. In conclusion, these results suggest that the feedback pen is a valuable tool to implement writing training in a tailor-made fashion for people with PD. Future studies should include larger sample sizes and different subgroups of PD for long-term training with the feedback pen.

  1. Learning feedback and feedforward control in a mirror-reversed visual environment.

    Science.gov (United States)

    Kasuga, Shoko; Telgen, Sebastian; Ushiba, Junichi; Nozaki, Daichi; Diedrichsen, Jörn

    2015-10-01

    When we learn a novel task, the motor system needs to acquire both feedforward and feedback control. Currently, little is known about how the learning of these two mechanisms relate to each other. In the present study, we tested whether feedforward and feedback control need to be learned separately, or whether they are learned as common mechanism when a new control policy is acquired. Participants were trained to reach to two lateral and one central target in an environment with mirror (left-right)-reversed visual feedback. One group was allowed to make online movement corrections, whereas the other group only received visual information after the end of the movement. Learning of feedforward control was assessed by measuring the accuracy of the initial movement direction to lateral targets. Feedback control was measured in the responses to sudden visual perturbations of the cursor when reaching to the central target. Although feedforward control improved in both groups, it was significantly better when online corrections were not allowed. In contrast, feedback control only adaptively changed in participants who received online feedback and remained unchanged in the group without online corrections. Our findings suggest that when a new control policy is acquired, feedforward and feedback control are learned separately, and that there may be a trade-off in learning between feedback and feedforward controllers. Copyright © 2015 the American Physiological Society.

  2. The role of visual and direct force feedback in robotics-assisted mitral valve annuloplasty.

    Science.gov (United States)

    Currie, Maria E; Talasaz, Ali; Rayman, Reiza; Chu, Michael W A; Kiaii, Bob; Peters, Terry; Trejos, Ana Luisa; Patel, Rajni

    2017-09-01

    The objective of this work was to determine the effect of both direct force feedback and visual force feedback on the amount of force applied to mitral valve tissue during ex vivo robotics-assisted mitral valve annuloplasty. A force feedback-enabled master-slave surgical system was developed to provide both visual and direct force feedback during robotics-assisted cardiac surgery. This system measured the amount of force applied by novice and expert surgeons to cardiac tissue during ex vivo mitral valve annuloplasty repair. The addition of visual (2.16 ± 1.67), direct (1.62 ± 0.86), or both visual and direct force feedback (2.15 ± 1.08) resulted in lower mean maximum force applied to mitral valve tissue while suturing compared with no force feedback (3.34 ± 1.93 N; P forces on cardiac tissue during robotics-assisted mitral valve annuloplasty suturing, force feedback may be required. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Effects of four types of non-obtrusive feedback on computer behaviour, task performance and comfort

    NARCIS (Netherlands)

    Korte, E.M.; Huijsmans, M.A.; de Jong, A.M.; van de Ven, J.G.M.; Ruijsendaal, M.

    2012-01-01

    This study investigated the effects of non-obtrusive feedback on continuous lifted hand/finger behaviour, task performance and comfort. In an experiment with 24 participants the effects of two visual and two tactile feedback signals were compared to a no-feedback condition in a computer task.

  4. Detecting delay in visual feedback of an action as a monitor of self recognition.

    Science.gov (United States)

    Hoover, Adria E N; Harris, Laurence R

    2012-10-01

    How do we distinguish "self" from "other"? The correlation between willing an action and seeing it occur is an important cue. We exploited the fact that this correlation needs to occur within a restricted temporal window in order to obtain a quantitative assessment of when a body part is identified as "self". We measured the threshold and sensitivity (d') for detecting a delay between movements of the finger (of both the dominant and non-dominant hands) and visual feedback as seen from four visual perspectives (the natural view, and mirror-reversed and/or inverted views). Each trial consisted of one presentation with minimum delay and another with a delay of between 33 and 150 ms. Participants indicated which presentation contained the delayed view. We varied the amount of efference copy available for this task by comparing performances for discrete movements and continuous movements. Discrete movements are associated with a stronger efference copy. Sensitivity to detect asynchrony between visual and proprioceptive information was significantly higher when movements were viewed from a "plausible" self perspective compared with when the view was reversed or inverted. Further, we found differences in performance between dominant and non-dominant hand finger movements across the continuous and single movements. Performance varied with the viewpoint from which the visual feedback was presented and on the efferent component such that optimal performance was obtained when the presentation was in the normal natural orientation and clear efferent information was available. Variations in sensitivity to visual/non-visual temporal incongruence with the viewpoint in which a movement is seen may help determine the arrangement of the underlying visual representation of the body.

  5. Rubber hand illusion under delayed visual feedback.

    Directory of Open Access Journals (Sweden)

    Sotaro Shimada

    Full Text Available BACKGROUND: Rubber hand illusion (RHI is a subject's illusion of the self-ownership of a rubber hand that was touched synchronously with their own hand. Although previous studies have confirmed that this illusion disappears when the rubber hand was touched asynchronously with the subject's hand, the minimum temporal discrepancy of these two events for attenuation of RHI has not been examined. METHODOLOGY/PRINCIPAL FINDINGS: In this study, various temporal discrepancies between visual and tactile stimulations were introduced by using a visual feedback delay experimental setup, and RHI effects in each temporal discrepancy condition were systematically tested. The results showed that subjects felt significantly greater RHI effects with temporal discrepancies of less than 300 ms compared with longer temporal discrepancies. The RHI effects on reaching performance (proprioceptive drift showed similar conditional differences. CONCLUSIONS/SIGNIFICANCE: Our results first demonstrated that a temporal discrepancy of less than 300 ms between visual stimulation of the rubber hand and tactile stimulation to the subject's own hand is preferable to induce strong sensation of RHI. We suggest that the time window of less than 300 ms is critical for multi-sensory integration processes constituting the self-body image.

  6. Effect of an auditory feedback substitution, tactilo-kinesthetic, or visual feedback on kinematics of pouring water from kettle into cup.

    Science.gov (United States)

    Portnoy, Sigal; Halaby, Orli; Dekel-Chen, Dotan; Dierick, Frédéric

    2015-11-01

    Pouring hot water from a kettle into a cup may prove a hazardous task, especially for the elderly or the visually-impaired. Individuals with deteriorating eyesight may endanger their hands by performing this task with both hands, relaying on tactilo-kinesthetic feedback (TKF). Auditory feedback (AF) may allow them to perform the task singlehandedly, thereby reducing the risk for injury. However since relying on an AF is not intuitive and requires practice, we aimed to determine if AF supplied during the task of pouring water can be used naturally as visual feedback (VF) following practice. For this purpose, we quantified, in young healthy sighted subjects (n = 20), the performance and kinematics of pouring water in the presence of three isolated feedbacks: visual, tactilo-kinesthetic, or auditory. There were no significant differences between the weights of spilled water in the AF condition compared to the TKF condition in the first, fifth or thirteenth trials. The subjectively-reported difficulty levels of using the TKF and the AF were significantly reduced between the first and thirteenth trials for both TKF (p = 0.01) and AF (p = 0.001). Trunk rotation during the first trial using the TKF was significantly lower than the trunk rotation while using VF. Also, shoulder adduction during the first trial using the TKF was significantly higher than the shoulder adduction while using the VF. During the AF trials, the median travel distance of the tip of the kettle was significantly reduced in the first trials so that in the thirtieth trial it did not differ significantly from the median travel distance during the thirtieth trial using TKF and VF. The maximal velocity of the tip of the kettle was constant for each of the feedback conditions but was higher in 10 cm s(-1) using VF than TKF, which was higher in 10 cm s(-1) from using AF. The smoothness of movement of the TKF and AF conditions, expressed by the normalized jerk score (NJSM), was one and two orders

  7. Effects of Real-Time Visual Feedback on Pre-Service Teachers' Singing

    Science.gov (United States)

    Leong, S.; Cheng, L.

    2014-01-01

    This pilot study focuses on the use real-time visual feedback technology (VFT) in vocal training. The empirical research has two aims: to ascertain the effectiveness of the real-time visual feedback software "Sing & See" in the vocal training of pre-service music teachers and the teachers' perspective on their experience with…

  8. Visual Acuity Testing: Feedback Affects Neither Outcome nor Reproducibility, but Leaves Participants Happier.

    Science.gov (United States)

    Bach, Michael; Schäfer, Kerstin

    2016-01-01

    Assessment of visual acuity is a well standardized procedure at least for expert opinions and clinical trials. It is often recommended not giving patients feedback on the correctness of their responses. As this viewpoint has not been quantitatively examined so far, we quantitatively assessed possible effects of feedback on visual acuity testing. In 40 normal participants we presented Landolt Cs in 8 orientations using the automated Freiburg Acuity Test (FrACT, feedback was provided in 2 x 4 conditions: (A) no feedback, (B) acoustic signals indicating correctness, (C)visual indication of correct orientation, and (D) a combination of (B) and (C). After each run the participants judged comfort. Main outcome measures were absolute visual acuity (logMAR), its test-retest agreement (limits of agreement) and participants' comfort estimates on a 5-step symmetric Likert scale. Feedback influenced acuity outcome significantly (p = 0.02), but with a tiny effect size: 0.02 logMAR poorer acuity for (D) compared to (A), even weaker effects for (B) and (C). Test-retest agreement was high (limits of agreement: ± 1.0 lines) and did not depend on feedback (p>0.5). The comfort ranking clearly differed, by 2 steps on the Likert scale: the condition (A)-no feedback-was on average "slightly uncomfortable", the other three conditions were "slightly comfortable" (pFeedback affected neither reproducibility nor the acuity outcome to any relevant extent. The participants, however, reported markedly greater comfort with any kind of feedback. We conclude that systematic feedback (as implemented in FrACT) offers nothing but advantages for routine use.

  9. Develop feedback system for intelligent dynamic resource allocation to improve application performance.

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, Ann C.; Brandt, James M.; Tucker, Thomas (Open Grid Computing, Inc., Austin, TX); Thompson, David

    2011-09-01

    This report provides documentation for the completion of the Sandia Level II milestone 'Develop feedback system for intelligent dynamic resource allocation to improve application performance'. This milestone demonstrates the use of a scalable data collection analysis and feedback system that enables insight into how an application is utilizing the hardware resources of a high performance computing (HPC) platform in a lightweight fashion. Further we demonstrate utilizing the same mechanisms used for transporting data for remote analysis and visualization to provide low latency run-time feedback to applications. The ultimate goal of this body of work is performance optimization in the face of the ever increasing size and complexity of HPC systems.

  10. Tactile Gap Detection Deteriorates during Bimanual Symmetrical Movements under Mirror Visual Feedback.

    Directory of Open Access Journals (Sweden)

    Janet H Bultitude

    Full Text Available It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual

  11. Improving training of laparoscopic tissue manipulation skills using various visual force feedback types

    NARCIS (Netherlands)

    Smit, Daan; Spruit, Edward; Dankelman, J.; Tuijthof, G.J.M.; Hamming, J; Horeman, T.

    2017-01-01

    Background Visual force feedback allows trainees to learn laparoscopic tissue manipulation skills. The aim of this experimental study was to find the most efficient visual force feedback method to acquire these skills. Retention and transfer validity to an untrained task were assessed. Methods

  12. Effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability.

    Science.gov (United States)

    Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn

    2018-01-01

    [Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.

  13. Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

    Science.gov (United States)

    Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

    2017-11-01

    Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical

  14. Eye movements in interception with delayed visual feedback.

    Science.gov (United States)

    Cámara, Clara; de la Malla, Cristina; López-Moliner, Joan; Brenner, Eli

    2018-04-19

    The increased reliance on electronic devices such as smartphones in our everyday life exposes us to various delays between our actions and their consequences. Whereas it is known that people can adapt to such delays, the mechanisms underlying such adaptation remain unclear. To better understand these mechanisms, the current study explored the role of eye movements in interception with delayed visual feedback. In two experiments, eye movements were recorded as participants tried to intercept a moving target with their unseen finger while receiving delayed visual feedback about their own movement. In Experiment 1, the target randomly moved in one of two different directions at one of two different velocities. The delay between the participant's finger movement and movement of the cursor that provided feedback about the finger movements was gradually increased. Despite the delay, participants followed the target with their gaze. They were quite successful at hitting the target with the cursor. Thus, they moved their finger to a position that was ahead of where they were looking. Removing the feedback showed that participants had adapted to the delay. In Experiment 2, the target always moved in the same direction and at the same velocity, while the cursor's delay varied across trials. Participants still always directed their gaze at the target. They adjusted their movement to the delay on each trial, often succeeding to intercept the target with the cursor. Since their gaze was always directed at the target, and they could not know the delay until the cursor started moving, participants must have been using peripheral vision of the delayed cursor to guide it to the target. Thus, people deal with delays by directing their gaze at the target and using both experience from previous trials (Experiment 1) and peripheral visual information (Experiment 2) to guide their finger in a way that will make the cursor hit the target.

  15. Combined mirror visual and auditory feedback therapy for upper limb phantom pain: a case report

    Directory of Open Access Journals (Sweden)

    Yan Kun

    2011-01-01

    Full Text Available Abstract Introduction Phantom limb sensation and phantom limb pain is a very common issue after amputations. In recent years there has been accumulating data implicating 'mirror visual feedback' or 'mirror therapy' as helpful in the treatment of phantom limb sensation and phantom limb pain. Case presentation We present the case of a 24-year-old Caucasian man, a left upper limb amputee, treated with mirror visual feedback combined with auditory feedback with improved pain relief. Conclusion This case may suggest that auditory feedback might enhance the effectiveness of mirror visual feedback and serve as a valuable addition to the complex multi-sensory processing of body perception in patients who are amputees.

  16. Real-time feedback on nonverbal clinical communication. Theoretical framework and clinician acceptance of ambient visual design.

    Science.gov (United States)

    Hartzler, A L; Patel, R A; Czerwinski, M; Pratt, W; Roseway, A; Chandrasekaran, N; Back, A

    2014-01-01

    This article is part of the focus theme of Methods of Information in Medicine on "Pervasive Intelligent Technologies for Health". Effective nonverbal communication between patients and clinicians fosters both the delivery of empathic patient-centered care and positive patient outcomes. Although nonverbal skill training is a recognized need, few efforts to enhance patient-clinician communication provide visual feedback on nonverbal aspects of the clinical encounter. We describe a novel approach that uses social signal processing technology (SSP) to capture nonverbal cues in real time and to display ambient visual feedback on control and affiliation--two primary, yet distinct dimensions of interpersonal nonverbal communication. To examine the design and clinician acceptance of ambient visual feedback on nonverbal communication, we 1) formulated a model of relational communication to ground SSP and 2) conducted a formative user study using mixed methods to explore the design of visual feedback. Based on a model of relational communication, we reviewed interpersonal communication research to map nonverbal cues to signals of affiliation and control evidenced in patient-clinician interaction. Corresponding with our formulation of this theoretical framework, we designed ambient real-time visualizations that reflect variations of affiliation and control. To explore clinicians' acceptance of this visual feedback, we conducted a lab study using the Wizard-of-Oz technique to simulate system use with 16 healthcare professionals. We followed up with seven of those participants through interviews to iterate on the design with a revised visualization that addressed emergent design considerations. Ambient visual feedback on non- verbal communication provides a theoretically grounded and acceptable way to provide clinicians with awareness of their nonverbal communication style. We provide implications for the design of such visual feedback that encourages empathic patient

  17. Effect- and Performance-Based Auditory Feedback on Interpersonal Coordination

    Directory of Open Access Journals (Sweden)

    Tong-Hun Hwang

    2018-03-01

    Full Text Available When two individuals interact in a collaborative task, such as carrying a sofa or a table, usually spatiotemporal coordination of individual motor behavior will emerge. In many cases, interpersonal coordination can arise independently of verbal communication, based on the observation of the partners' movements and/or the object's movements. In this study, we investigate how social coupling between two individuals can emerge in a collaborative task under different modes of perceptual information. A visual reference condition was compared with three different conditions with new types of additional auditory feedback provided in real time: effect-based auditory feedback, performance-based auditory feedback, and combined effect/performance-based auditory feedback. We have developed a new paradigm in which the actions of both participants continuously result in a seamlessly merged effect on an object simulated by a tablet computer application. Here, participants should temporally synchronize their movements with a 90° phase difference and precisely adjust the finger dynamics in order to keep the object (a ball accurately rotating on a given circular trajectory on the tablet. Results demonstrate that interpersonal coordination in a joint task can be altered by different kinds of additional auditory information in various ways.

  18. Impact of online visual feedback on motor acquisition and retention when learning to reach in a force field.

    Science.gov (United States)

    Batcho, C S; Gagné, M; Bouyer, L J; Roy, J S; Mercier, C

    2016-11-19

    When subjects learn a novel motor task, several sources of feedback (proprioceptive, visual or auditory) contribute to the performance. Over the past few years, several studies have investigated the role of visual feedback in motor learning, yet evidence remains conflicting. The aim of this study was therefore to investigate the role of online visual feedback (VFb) on the acquisition and retention stages of motor learning associated with training in a reaching task. Thirty healthy subjects made ballistic reaching movements with their dominant arm toward two targets, on 2 consecutive days using a robotized exoskeleton (KINARM). They were randomly assigned to a group with (VFb) or without (NoVFb) VFb of index position during movement. On day 1, the task was performed before (baseline) and during the application of a velocity-dependent resistive force field (adaptation). To assess retention, participants repeated the task with the force field on day 2. Motor learning was characterized by: (1) the final endpoint error (movement accuracy) and (2) the initial angle (iANG) of deviation (motor planning). Even though both groups showed motor adaptation, the NoVFb-group exhibited slower learning and higher final endpoint error than the VFb-group. In some condition, subjects trained without visual feedback used more curved initial trajectories to anticipate for the perturbation. This observation suggests that learning to reach targets in a velocity-dependent resistive force field is possible even when feedback is limited. However, the absence of VFb leads to different strategies that were only apparent when reaching toward the most challenging target. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

    Science.gov (United States)

    Leving, Marika T; Vegter, Riemer J K; Hartog, Johanneke; Lamoth, Claudine J C; de Groot, Sonja; van der Woude, Lucas H V

    2015-01-01

    It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process. 17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability. The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group. These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear

  20. Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.

    Directory of Open Access Journals (Sweden)

    Marika T Leving

    Full Text Available It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process.17 Participants received visual feedback-based practice (feedback group and 15 participants received regular practice (natural learning group. Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block and optimize it in the prescribed direction (2nd 4-min block. To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability.The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group.These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not

  1. Age-specific effects of mirror-muscle activity on cross-limb adaptations under mirror and non-mirror visual feedback conditions.

    Directory of Open Access Journals (Sweden)

    Paola eReissig

    2015-12-01

    Full Text Available Cross-limb transfer (CLT describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53 engaged in a short-term training regime (300 movements involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb. Bilateral performance was examined before, during and following the training. Furthermore, we measured corticospinal excitability (using TMS at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (all ps > 0.1. Training also elicited bilateral increases in corticospinal excitability (p < 0.05. For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47, whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60. The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the

  2. Visual feedback attenuates mean concentric barbell velocity loss, and improves motivation, competitiveness, and perceived workload in male adolescent athletes.

    Science.gov (United States)

    Weakley, Jonathon Js; Wilson, Kyle M; Till, Kevin; Read, Dale B; Darrall-Jones, Joshua; Roe, Gregory; Phibbs, Padraic J; Jones, Ben

    2017-07-12

    It is unknown whether instantaneous visual feedback of resistance training outcomes can enhance barbell velocity in younger athletes. Therefore, the purpose of this study was to quantify the effects of visual feedback on mean concentric barbell velocity in the back squat, and to identify changes in motivation, competitiveness, and perceived workload. In a randomised-crossover design (Feedback vs. Control) feedback of mean concentric barbell velocity was or was not provided throughout a set of 10 repetitions in the barbell back squat. Magnitude-based inferences were used to assess changes between conditions, with almost certainly greater differences in mean concentric velocity between the Feedback (0.70 ±0.04 m·s) and Control (0.65 ±0.05 m·s) observed. Additionally, individual repetition mean concentric velocity ranged from possibly (repetition number two: 0.79 ±0.04 vs. 0.78 ±0.04 m·s) to almost certainly (repetition number 10: 0.58 ±0.05 vs. 0.49 ±0.05 m·s) greater when provided feedback, while almost certain differences were observed in motivation, competitiveness, and perceived workload, respectively. Providing adolescent male athletes with visual kinematic information while completing resistance training is beneficial for the maintenance of barbell velocity during a training set, potentially enhancing physical performance. Moreover, these improvements were observed alongside increases in motivation, competitiveness and perceived workload providing insight into the underlying mechanisms responsible for the performance gains observed. Given the observed maintenance of barbell velocity during a training set, practitioners can use this technique to manipulate training outcomes during resistance training.

  3. The influence of verbal training and visual feedback on manual wheelchair propulsion.

    Science.gov (United States)

    DeGroot, Keri K; Hollingsworth, Holly H; Morgan, Kerri A; Morris, Carrie L; Gray, David B

    2009-03-01

    To determine if verbal training with visual feedback improved manual wheelchair propulsion; to examine propulsion differences between an individual with paraplegia and an individual with tetraplegia. Quasi-experimental study: Nine manual wheelchair-using adults participated in propulsion assessments and training. Baseline propulsion performance was measured on several tasks on different surfaces. Participants were trained on a wheelchair treadmill with verbal and visual feedback to increase push length, reduce push frequency and to modify propulsion pattern. Handrim biomechanics were measured with an instrumented wheel. Changes in propulsion were assessed. Differences in propulsion characteristics between a participant with paraplegia and a participant with tetraplegia were examined. Push length increased (p propulsion characteristics between a participant with paraplegia and a participant with tetraplegia. Verbal training may produce changes in push biomechanics of manual wheelchair users. Longer training periods may be needed to sustain propulsion changes. Findings from this study support other studies that have shown propulsion differences between people with tetraplegia and paraplegia. Propulsion training for populations with upper-extremity impairments warrants further study.

  4. Distinct Feedforward and Feedback Effects of Microstimulation in Visual Cortex Reveal Neural Mechanisms of Texture Segregation.

    Science.gov (United States)

    Klink, P Christiaan; Dagnino, Bruno; Gariel-Mathis, Marie-Alice; Roelfsema, Pieter R

    2017-07-05

    The visual cortex is hierarchically organized, with low-level areas coding for simple features and higher areas for complex ones. Feedforward and feedback connections propagate information between areas in opposite directions, but their functional roles are only partially understood. We used electrical microstimulation to perturb the propagation of neuronal activity between areas V1 and V4 in monkeys performing a texture-segregation task. In both areas, microstimulation locally caused a brief phase of excitation, followed by inhibition. Both these effects propagated faithfully in the feedforward direction from V1 to V4. Stimulation of V4, however, caused little V1 excitation, but it did yield a delayed suppression during the late phase of visually driven activity. This suppression was pronounced for the V1 figure representation and weaker for background representations. Our results reveal functional differences between feedforward and feedback processing in texture segregation and suggest a specific modulating role for feedback connections in perceptual organization. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. A software module for implementing auditory and visual feedback on a video-based eye tracking system

    Science.gov (United States)

    Rosanlall, Bharat; Gertner, Izidor; Geri, George A.; Arrington, Karl F.

    2016-05-01

    We describe here the design and implementation of a software module that provides both auditory and visual feedback of the eye position measured by a commercially available eye tracking system. The present audio-visual feedback module (AVFM) serves as an extension to the Arrington Research ViewPoint EyeTracker, but it can be easily modified for use with other similar systems. Two modes of audio feedback and one mode of visual feedback are provided in reference to a circular area-of-interest (AOI). Auditory feedback can be either a click tone emitted when the user's gaze point enters or leaves the AOI, or a sinusoidal waveform with frequency inversely proportional to the distance from the gaze point to the center of the AOI. Visual feedback is in the form of a small circular light patch that is presented whenever the gaze-point is within the AOI. The AVFM processes data that are sent to a dynamic-link library by the EyeTracker. The AVFM's multithreaded implementation also allows real-time data collection (1 kHz sampling rate) and graphics processing that allow display of the current/past gaze-points as well as the AOI. The feedback provided by the AVFM described here has applications in military target acquisition and personnel training, as well as in visual experimentation, clinical research, marketing research, and sports training.

  6. OpinionSeer: interactive visualization of hotel customer feedback.

    Science.gov (United States)

    Wu, Yingcai; Wei, Furu; Liu, Shixia; Au, Norman; Cui, Weiwei; Zhou, Hong; Qu, Huamin

    2010-01-01

    The rapid development of Web technology has resulted in an increasing number of hotel customers sharing their opinions on the hotel services. Effective visual analysis of online customer opinions is needed, as it has a significant impact on building a successful business. In this paper, we present OpinionSeer, an interactive visualization system that could visually analyze a large collection of online hotel customer reviews. The system is built on a new visualization-centric opinion mining technique that considers uncertainty for faithfully modeling and analyzing customer opinions. A new visual representation is developed to convey customer opinions by augmenting well-established scatterplots and radial visualization. To provide multiple-level exploration, we introduce subjective logic to handle and organize subjective opinions with degrees of uncertainty. Several case studies illustrate the effectiveness and usefulness of OpinionSeer on analyzing relationships among multiple data dimensions and comparing opinions of different groups. Aside from data on hotel customer feedback, OpinionSeer could also be applied to visually analyze customer opinions on other products or services.

  7. Use of visual CO2 feedback as a retrofit solution for improving classroom air quality.

    Science.gov (United States)

    Wargocki, P; Da Silva, N A F

    2015-02-01

    Carbon dioxide (CO2 ) sensors that provide a visual indication were installed in classrooms during normal school operation. During 2-week periods, teachers and students were instructed to open the windows in response to the visual CO2 feedback in 1 week and open them, as they would normally do, without visual feedback, in the other week. In the heating season, two pairs of classrooms were monitored, one pair naturally and the other pair mechanically ventilated. In the cooling season, two pairs of naturally ventilated classrooms were monitored, one pair with split cooling in operation and the other pair with no cooling. Classrooms were matched by grade. Providing visual CO2 feedback reduced CO2 levels, as more windows were opened in this condition. This increased energy use for heating and reduced the cooling requirement in summertime. Split cooling reduced the frequency of window opening only when no visual CO2 feedback was present. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Reproducibility of The Abdominal and Chest Wall Position by Voluntary Breath-Hold Technique Using a Laser-Based Monitoring and Visual Feedback System

    International Nuclear Information System (INIS)

    Nakamura, Katsumasa; Shioyama, Yoshiyuki; Nomoto, Satoru; Ohga, Saiji; Toba, Takashi; Yoshitake, Tadamasa; Anai, Shigeo; Terashima, Hiromi; Honda, Hiroshi

    2007-01-01

    Purpose: The voluntary breath-hold (BH) technique is a simple method to control the respiration-related motion of a tumor during irradiation. However, the abdominal and chest wall position may not be accurately reproduced using the BH technique. The purpose of this study was to examine whether visual feedback can reduce the fluctuation in wall motion during BH using a new respiratory monitoring device. Methods and Materials: We developed a laser-based BH monitoring and visual feedback system. For this study, five healthy volunteers were enrolled. The volunteers, practicing abdominal breathing, performed shallow end-expiration BH (SEBH), shallow end-inspiration BH (SIBH), and deep end-inspiration BH (DIBH) with or without visual feedback. The abdominal and chest wall positions were measured at 80-ms intervals during BHs. Results: The fluctuation in the chest wall position was smaller than that of the abdominal wall position. The reproducibility of the wall position was improved by visual feedback. With a monitoring device, visual feedback reduced the mean deviation of the abdominal wall from 2.1 ± 1.3 mm to 1.5 ± 0.5 mm, 2.5 ± 1.9 mm to 1.1 ± 0.4 mm, and 6.6 ± 2.4 mm to 2.6 ± 1.4 mm in SEBH, SIBH, and DIBH, respectively. Conclusions: Volunteers can perform the BH maneuver in a highly reproducible fashion when informed about the position of the wall, although in the case of DIBH, the deviation in the wall position remained substantial

  9. Haptic force-feedback devices for the office computer: performance and musculoskeletal loading issues.

    Science.gov (United States)

    Dennerlein, J T; Yang, M C

    2001-01-01

    Pointing devices, essential input tools for the graphical user interface (GUI) of desktop computers, require precise motor control and dexterity to use. Haptic force-feedback devices provide the human operator with tactile cues, adding the sense of touch to existing visual and auditory interfaces. However, the performance enhancements, comfort, and possible musculoskeletal loading of using a force-feedback device in an office environment are unknown. Hypothesizing that the time to perform a task and the self-reported pain and discomfort of the task improve with the addition of force feedback, 26 people ranging in age from 22 to 44 years performed a point-and-click task 540 times with and without an attractive force field surrounding the desired target. The point-and-click movements were approximately 25% faster with the addition of force feedback (paired t-tests, p user discomfort and pain, as measured through a questionnaire, were also smaller with the addition of force feedback (p device improves performance, and potentially reduces musculoskeletal loading during mouse use. Actual or potential applications of this research include human-computer interface design, specifically that of the pointing device extensively used for the graphical user interface.

  10. The Effects of Visual Feedback on CPR Skill Retention in Graduate Student Athletic Trainers

    Directory of Open Access Journals (Sweden)

    Michael G. Miller

    2015-09-01

    Full Text Available Context: Studies examining the effectiveness of cardiopulmonary resuscitation (CPR chest compressions have found compression depth and rate to be less than optimal and recoil to full release to be incomplete. Objective: To determine if visual feedback affects the rate and depth of chest compressions and chest recoil values during CPR training of athletic trainers and to determine retention of proficiency over time. Design: Pre-test, post-test. Setting: Medical simulation laboratory. Participants: Eleven females and one male (23.08+.51 years old, from an Athletic Training Graduate Program. All participants were Certified Athletic Trainers (1.12+.46 years of experience and certified in CPR for the Professional Rescuer. Interventions: Participants completed a pre-test, practice sessions, and a post-test on a SimMan® (Laerdal Medical manikin with visual feedback of skills in real time. After the pre-test, participants received feedback by the investigators. Participants completed practice sessions as needed (range=1-4 sessions, until they reached 100% skill proficiency. After achieving proficiency, participants returned 8 weeks later to perform the CPR skills. Main Outcome Measures: The average of all compression outcome measures (rate, depth, recoil was captured every 10 seconds (6x per min. All participants performed 5 cycles of 30 compressions. A two-tailed paired samples t-test (pre to post was used to compare rate of chest compressions, depth of chest compressions, and recoil of the chest. Significance was set a priori at pResults: There was a significant difference between pre and post-test compression depth average, p=.002. The pre-depth average was 41mm + 9.83mm compared to the post-depth average of 52.26mm + 5mm. There were no significant differences between pre and post-test chest compression rates and recoil. Conclusions: The use of a simulated manikin with visual feedback facilitated participants to reach the recommended compression

  11. Vibrotactile Feedback for Brain-Computer Interface Operation

    Directory of Open Access Journals (Sweden)

    Febo Cincotti

    2007-01-01

    Full Text Available To be correctly mastered, brain-computer interfaces (BCIs need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (including 3 with spinal cord injury, we compared vibrotactile and visual feedback, addressing: (I the feasibility of subjects' training to master their EEG rhythms using tactile feedback; (II the compatibility of this form of feedback in presence of a visual distracter; (III the performance in presence of a complex visual task on the same (visual or different (tactile sensory channel. The stimulation protocol we developed supports a general usage of the tactors; preliminary experimentations. All studies indicated that the vibrotactile channel can function as a valuable feedback modality with reliability comparable to the classical visual feedback. Advantages of using a vibrotactile feedback emerged when the visual channel was highly loaded by a complex task. In all experiments, vibrotactile feedback felt, after some training, more natural for both controls and SCI users.

  12. Motor sequence learning occurs despite disrupted visual and proprioceptive feedback

    Directory of Open Access Journals (Sweden)

    Boyd Lara A

    2008-07-01

    Full Text Available Abstract Background Recent work has demonstrated the importance of proprioception for the development of internal representations of the forces encountered during a task. Evidence also exists for a significant role for proprioception in the execution of sequential movements. However, little work has explored the role of proprioceptive sensation during the learning of continuous movement sequences. Here, we report that the repeated segment of a continuous tracking task can be learned despite peripherally altered arm proprioception and severely restricted visual feedback regarding motor output. Methods Healthy adults practiced a continuous tracking task over 2 days. Half of the participants experienced vibration that altered proprioception of shoulder flexion/extension of the active tracking arm (experimental condition and half experienced vibration of the passive resting arm (control condition. Visual feedback was restricted for all participants. Retention testing was conducted on a separate day to assess motor learning. Results Regardless of vibration condition, participants learned the repeated segment demonstrated by significant improvements in accuracy for tracking repeated as compared to random continuous movement sequences. Conclusion These results suggest that with practice, participants were able to use residual afferent information to overcome initial interference of tracking ability related to altered proprioception and restricted visual feedback to learn a continuous motor sequence. Motor learning occurred despite an initial interference of tracking noted during acquisition practice.

  13. Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

    Science.gov (United States)

    Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

    2016-02-01

    Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

  14. The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation.

    Science.gov (United States)

    Ceux, Tanja; Montagne, Gilles; Buekers, Martinus J

    2010-12-01

    The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization modes (in-phase, anti-phase, and intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization mode in contrast to the less stable anti-phase and intermediate mode. Our findings suggest that the complexity of the synchronization mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Visual feedback of tongue movement for novel speech sound learning

    Directory of Open Access Journals (Sweden)

    William F Katz

    2015-11-01

    Full Text Available Pronunciation training studies have yielded important information concerning the processing of audiovisual (AV information. Second language (L2 learners show increased reliance on bottom-up, multimodal input for speech perception (compared to monolingual individuals. However, little is known about the role of viewing one’s own speech articulation processes during speech training. The current study investigated whether real-time, visual feedback for tongue movement can improve a speaker’s learning of non-native speech sounds. An interactive 3D tongue visualization system based on electromagnetic articulography (EMA was used in a speech training experiment. Native speakers of American English produced a novel speech sound (/ɖ̠/; a voiced, coronal, palatal stop before, during, and after trials in which they viewed their own speech movements using the 3D model. Talkers’ productions were evaluated using kinematic (tongue-tip spatial positioning and acoustic (burst spectra measures. The results indicated a rapid gain in accuracy associated with visual feedback training. The findings are discussed with respect to neural models for multimodal speech processing.

  16. Influence of visual feedback on knee extensor isokinetic concentric ...

    African Journals Online (AJOL)

    Isokinetic normative data can be invaluable in identifying an individual's strengths and weaknesses, and thus lead to a more effective use of the individual's time to minimise or overcome his weaknesses while maintaining or improving existing strength. However, visual feedback (VF) may significantly affect the result of ...

  17. Movement retraining using real-time feedback of performance.

    Science.gov (United States)

    Hunt, Michael Anthony

    2013-01-17

    Any modification of movement - especially movement patterns that have been honed over a number of years - requires re-organization of the neuromuscular patterns responsible for governing the movement performance. This motor learning can be enhanced through a number of methods that are utilized in research and clinical settings alike. In general, verbal feedback of performance in real-time or knowledge of results following movement is commonly used clinically as a preliminary means of instilling motor learning. Depending on patient preference and learning style, visual feedback (e.g. through use of a mirror or different types of video) or proprioceptive guidance utilizing therapist touch, are used to supplement verbal instructions from the therapist. Indeed, a combination of these forms of feedback is commonplace in the clinical setting to facilitate motor learning and optimize outcomes. Laboratory-based, quantitative motion analysis has been a mainstay in research settings to provide accurate and objective analysis of a variety of movements in healthy and injured populations. While the actual mechanisms of capturing the movements may differ, all current motion analysis systems rely on the ability to track the movement of body segments and joints and to use established equations of motion to quantify key movement patterns. Due to limitations in acquisition and processing speed, analysis and description of the movements has traditionally occurred offline after completion of a given testing session. This paper will highlight a new supplement to standard motion analysis techniques that relies on the near instantaneous assessment and quantification of movement patterns and the display of specific movement characteristics to the patient during a movement analysis session. As a result, this novel technique can provide a new method of feedback delivery that has advantages over currently used feedback methods.

  18. Manipulating the fidelity of lower extremity visual feedback to identify obstacle negotiation strategies in immersive virtual reality.

    Science.gov (United States)

    Kim, Aram; Zhou, Zixuan; Kretch, Kari S; Finley, James M

    2017-07-01

    The ability to successfully navigate obstacles in our environment requires integration of visual information about the environment with estimates of our body's state. Previous studies have used partial occlusion of the visual field to explore how information about the body and impending obstacles are integrated to mediate a successful clearance strategy. However, because these manipulations often remove information about both the body and obstacle, it remains to be seen how information about the lower extremities alone is utilized during obstacle crossing. Here, we used an immersive virtual reality (VR) interface to explore how visual feedback of the lower extremities influences obstacle crossing performance. Participants wore a head-mounted display while walking on treadmill and were instructed to step over obstacles in a virtual corridor in four different feedback trials. The trials involved: (1) No visual feedback of the lower extremities, (2) an endpoint-only model, (3) a link-segment model, and (4) a volumetric multi-segment model. We found that the volumetric model improved success rate, placed their trailing foot before crossing and leading foot after crossing more consistently, and placed their leading foot closer to the obstacle after crossing compared to no model. This knowledge is critical for the design of obstacle negotiation tasks in immersive virtual environments as it may provide information about the fidelity necessary to reproduce ecologically valid practice environments.

  19. Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

    Science.gov (United States)

    Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

    2016-02-01

    Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

  20. Audio-Visual Feedback for Self-monitoring Posture in Ballet Training

    DEFF Research Database (Denmark)

    Knudsen, Esben Winther; Hølledig, Malte Lindholm; Bach-Nielsen, Sebastian Siem

    2017-01-01

    An application for ballet training is presented that monitors the posture position (straightness of the spine and rotation of the pelvis) deviation from the ideal position in real-time. The human skeletal data is acquired through a Microsoft Kinect v2. The movement of the student is mirrored......-coded. In an experiment with 9-12 year-old dance students from a ballet school, comparing the audio-visual feedback modality with no feedback leads to an increase in posture accuracy (p

  1. Reducing Trunk Compensation in Stroke Survivors: A Randomized Crossover Trial Comparing Visual and Force Feedback Modalities.

    Science.gov (United States)

    Valdés, Bulmaro Adolfo; Schneider, Andrea Nicole; Van der Loos, H F Machiel

    2017-10-01

    To investigate whether the compensatory trunk movements of stroke survivors observed during reaching tasks can be decreased by force and visual feedback, and to examine whether one of these feedback modalities is more efficacious than the other in reducing this compensatory tendency. Randomized crossover trial. University research laboratory. Community-dwelling older adults (N=15; 5 women; mean age, 64±11y) with hemiplegia from nontraumatic hemorrhagic or ischemic stroke (>3mo poststroke), recruited from stroke recovery groups, the research group's website, and the community. In a single session, participants received augmented feedback about their trunk compensation during a bimanual reaching task. Visual feedback (60 trials) was delivered through a computer monitor, and force feedback (60 trials) was delivered through 2 robotic devices. Primary outcome measure included change in anterior trunk displacement measured by motion tracking camera. Secondary outcomes included trunk rotation, index of curvature (measure of straightness of hands' path toward target), root mean square error of hands' movement (differences between hand position on every iteration of the program), completion time for each trial, and posttest questionnaire to evaluate users' experience and system's usability. Both visual (-45.6% [45.8 SD] change from baseline, P=.004) and force (-41.1% [46.1 SD], P=.004) feedback were effective in reducing trunk compensation. Scores on secondary outcome measures did not improve with either feedback modality. Neither feedback condition was superior. Visual and force feedback show promise as 2 modalities that could be used to decrease trunk compensation in stroke survivors during reaching tasks. It remains to be established which one of these 2 feedback modalities is more efficacious than the other as a cue to reduce compensatory trunk movement. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  2. The persistence of a visual dominance effect in a telemanipulator task: A comparison between visual and electrotactile feedback

    Science.gov (United States)

    Gaillard, J. P.

    1981-01-01

    The possibility to use an electrotactile stimulation in teleoperation and to observe the interpretation of such information as a feedback to the operator was investigated. It is proposed that visual feedback is more informative than an electrotactile one; and that complex electrotactile feedback slows down both the motor decision and motor response processes, is processed as an all or nothing signal, and bypasses the receptive structure and accesses directly in a working memory where information is sequentially processed and where memory is limited in treatment capacity. The electrotactile stimulation is used as an alerting signal. It is suggested that the visual dominance effect is the result of the advantage of both a transfer function and a sensory memory register where information is pretreated and memorized for a short time. It is found that dividing attention has an effect on the acquisition of the information but not on the subsequent decision processes.

  3. Automated numerical simulation of biological pattern formation based on visual feedback simulation framework.

    Science.gov (United States)

    Sun, Mingzhu; Xu, Hui; Zeng, Xingjuan; Zhao, Xin

    2017-01-01

    There are various fantastic biological phenomena in biological pattern formation. Mathematical modeling using reaction-diffusion partial differential equation systems is employed to study the mechanism of pattern formation. However, model parameter selection is both difficult and time consuming. In this paper, a visual feedback simulation framework is proposed to calculate the parameters of a mathematical model automatically based on the basic principle of feedback control. In the simulation framework, the simulation results are visualized, and the image features are extracted as the system feedback. Then, the unknown model parameters are obtained by comparing the image features of the simulation image and the target biological pattern. Considering two typical applications, the visual feedback simulation framework is applied to fulfill pattern formation simulations for vascular mesenchymal cells and lung development. In the simulation framework, the spot, stripe, labyrinthine patterns of vascular mesenchymal cells, the normal branching pattern and the branching pattern lacking side branching for lung branching are obtained in a finite number of iterations. The simulation results indicate that it is easy to achieve the simulation targets, especially when the simulation patterns are sensitive to the model parameters. Moreover, this simulation framework can expand to other types of biological pattern formation.

  4. Task clarification, performance feedback, and social praise: Procedures for improving the customer service of bank tellers.

    Science.gov (United States)

    Crowell, C R; Anderson, D C; Abel, D M; Sergio, J P

    1988-01-01

    Customer service for bank tellers was defined in terms of 11 verbal behavior categories. An audio-recording system was used to track the occurrence of behaviors in these categories for six retail banking tellers. Three behavior management interventions (task clarification, performance feedback, and social praise), applied in sequence, were designed to improve overall teller performance with regard to the behavioral categories targeted. Clarification was accomplished by providing clear delineation of the various target categories, with specific examples of the behaviors in each. Feedback entailed presentation of ongoing verbal and visual information regarding teller performance. Praise consisted of verbal recognition of teller performance by branch managers. Results showed that clarification effects emerged quickly, producing an overall increase in desired behaviors of 12% over baseline. Feedback and praise effects occurred more gradually, resulting in overall increases of 6% and 7%, respectively. A suspension of all procedures led to a decline in overall performance, whereas reinstatement of feedback and praise was again accompanied by performance improvement. These findings extend the generality of behavior management applications and help to distinguish between possible antecedent and consequent effects of performance feedback.

  5. Watch what you type: the role of visual feedback from the screen and hands in skilled typewriting.

    Science.gov (United States)

    Snyder, Kristy M; Logan, Gordon D; Yamaguchi, Motonori

    2015-01-01

    Skilled typing is controlled by two hierarchically structured processing loops (Logan & Crump, 2011): The outer loop, which produces words, commands the inner loop, which produces keystrokes. Here, we assessed the interplay between the two loops by investigating how visual feedback from the screen (responses either were or were not echoed on the screen) and the hands (the hands either were or were not covered with a box) influences the control of skilled typing. Our results indicated, first, that the reaction time of the first keystroke was longer when responses were not echoed than when they were. Also, the interkeystroke interval (IKSI) was longer when the hands were covered than when they were visible, and the IKSI for responses that were not echoed was longer when explicit error monitoring was required (Exp. 2) than when it was not required (Exp. 1). Finally, explicit error monitoring was more accurate when response echoes were present than when they were absent, and implicit error monitoring (i.e., posterror slowing) was not influenced by visual feedback from the screen or the hands. These findings suggest that the outer loop adjusts the inner-loop timing parameters to compensate for reductions in visual feedback. We suggest that these adjustments are preemptive control strategies designed to execute keystrokes more cautiously when visual feedback from the hands is absent, to generate more cautious motor programs when visual feedback from the screen is absent, and to enable enough time for the outer loop to monitor keystrokes when visual feedback from the screen is absent and explicit error reports are required.

  6. Influence of Force and Torque Feedback on Operator Performance in a VR-Based Suturing Task

    Directory of Open Access Journals (Sweden)

    L. Santos-Carreras

    2010-01-01

    Full Text Available The introduction of Minimally Invasive Surgery (MIS has revolutionised surgical care, considerably improving the quality of many surgical procedures. Technological advances, particularly in robotic surgery systems, have reduced the complexity of such an approach, paving the way for even less invasive surgical trends. However, the fact that haptic feedback has been progressively lost through this transition is an issue that to date has not been solved. Whereas traditional open surgery provides full haptic feedback, the introduction of MIS has eliminated the possibility of direct palpation and tactile exploration. Nevertheless, these procedures still provide a certain amount of force feedback through the rigid laparoscopic tool. Many of the current telemanipulated robotic surgical systems in return do not provide full haptic feedback, which to a certain extent can be explained by the requirement of force sensors integrated into the tools of the slave robot and actuators in the surgeon’s master console. In view of the increased complexity and cost, the benefit of haptic feedback is open to dispute. Nevertheless, studies have shown the importance of haptic feedback, especially when visual feedback is unreliable or absent. In order to explore the importance of haptic feedback for the surgeon’s master console of a novel teleoperated robotic surgical system, we have identified a typical surgical task where performance could potentially be improved by haptic feedback, and investigate performance with and without this feedback. Two rounds of experiments are performed with 10 subjects, six of them with a medical background. Results show that feedback conditions, including force feedback, significantly improve task performance independently of the operator’s suturing experience. There is, however, no further significant improvement when torque feedback is added. Consequently, it is deduced that force feedback in translations improves subject

  7. Control Framework for Dexterous Manipulation Using Dynamic Visual Servoing and Tactile Sensors’ Feedback

    Directory of Open Access Journals (Sweden)

    Carlos A. Jara

    2014-01-01

    Full Text Available Tactile sensors play an important role in robotics manipulation to perform dexterous and complex tasks. This paper presents a novel control framework to perform dexterous manipulation with multi-fingered robotic hands using feedback data from tactile and visual sensors. This control framework permits the definition of new visual controllers which allow the path tracking of the object motion taking into account both the dynamics model of the robot hand and the grasping force of the fingertips under a hybrid control scheme. In addition, the proposed general method employs optimal control to obtain the desired behaviour in the joint space of the fingers based on an indicated cost function which determines how the control effort is distributed over the joints of the robotic hand. Finally, authors show experimental verifications on a real robotic manipulation system for some of the controllers derived from the control framework.

  8. Effect of task-related continuous auditory feedback during learning of tracking motion exercises

    Directory of Open Access Journals (Sweden)

    Rosati Giulio

    2012-10-01

    Full Text Available Abstract Background This paper presents the results of a set of experiments in which we used continuous auditory feedback to augment motor training exercises. This feedback modality is mostly underexploited in current robotic rehabilitation systems, which usually implement only very basic auditory interfaces. Our hypothesis is that properly designed continuous auditory feedback could be used to represent temporal and spatial information that could in turn, improve performance and motor learning. Methods We implemented three different experiments on healthy subjects, who were asked to track a target on a screen by moving an input device (controller with their hand. Different visual and auditory feedback modalities were envisaged. The first experiment investigated whether continuous task-related auditory feedback can help improve performance to a greater extent than error-related audio feedback, or visual feedback alone. In the second experiment we used sensory substitution to compare different types of auditory feedback with equivalent visual feedback, in order to find out whether mapping the same information on a different sensory channel (the visual channel yielded comparable effects with those gained in the first experiment. The final experiment applied a continuously changing visuomotor transformation between the controller and the screen and mapped kinematic information, computed in either coordinate system (controller or video, to the audio channel, in order to investigate which information was more relevant to the user. Results Task-related audio feedback significantly improved performance with respect to visual feedback alone, whilst error-related feedback did not. Secondly, performance in audio tasks was significantly better with respect to the equivalent sensory-substituted visual tasks. Finally, with respect to visual feedback alone, video-task-related sound feedback decreased the tracking error during the learning of a novel

  9. Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

    2015-05-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Physician performance feedback in a Canadian academic center.

    Science.gov (United States)

    Garvin, Dennis; Worthington, James; McGuire, Shaun; Burgetz, Stephanie; Forster, Alan J; Patey, Andrea; Gerin-Lajoie, Caroline; Turnbull, Jeffrey; Roth, Virginia

    2017-10-02

    Purpose This paper aims at the implementation and early evaluation of a comprehensive, formative annual physician performance feedback process in a large academic health-care organization. Design/methodology/approach A mixed methods approach was used to introduce a formative feedback process to provide physicians with comprehensive feedback on performance and to support professional development. This initiative responded to organization-wide engagement surveys through which physicians identified effective performance feedback as a priority. In 2013, physicians primarily affiliated with the organization participated in a performance feedback process, and physician satisfaction and participant perceptions were explored through participant survey responses and physician leader focus groups. Training was required for physician leaders prior to conducting performance feedback discussions. Findings This process was completed by 98 per cent of eligible physicians, and 30 per cent completed an evaluation survey. While physicians endorsed the concept of a formative feedback process, process improvement opportunities were identified. Qualitative analysis revealed the following process improvement themes: simplify the tool, ensure leaders follow process, eliminate redundancies in data collection (through academic or licensing requirements) and provide objective quality metrics. Following physician leader training on performance feedback, 98 per cent of leaders who completed an evaluation questionnaire agreed or strongly agreed that the performance feedback process was useful and that training objectives were met. Originality/value This paper introduces a physician performance feedback model, leadership training approach and first-year implementation outcomes. The results of this study will be useful to health administrators and physician leaders interested in implementing physician performance feedback or improving physician engagement.

  11. Real-Time Knee Adduction Moment Feedback for Gait Retraining Through Visual and Tactile Displays

    KAUST Repository

    Wheeler, Jason W.; Shull, Pete B.; Besier, Thor F.

    2011-01-01

    The external knee adduction moment (KAM) measured during gait is an indicator of tibiofemoral joint osteoarthritis progression and various strategies have been proposed to lower it. Gait retraining has been shown to be an effective, noninvasive approach for lowering the KAM. We present a new gait retraining approach in which the KAM is fed back to subjects in real-time during ambulation. A study was conducted in which 16 healthy subjects learned to alter gait patterns to lower the KAM through visual or tactile (vibration) feedback. Participants converged on a comfortable gait in just a few minutes by using the feedback to iterate on various kinematic modifications. All subjects adopted altered gait patterns with lower KAM compared with normal ambulation (average reduction of 20.7%). Tactile and visual feedbacks were equally effective for real-time training, although subjects using tactile feedback took longer to converge on an acceptable gait. This study shows that real-time feedback of the KAM can greatly increase the effectiveness and efficiency of subject-specific gait retraining compared with conventional methods. © 2011 American Society of Mechanical Engineers.

  12. A new visual feedback-based magnetorheological haptic master for robot-assisted minimally invasive surgery

    Science.gov (United States)

    Choi, Seung-Hyun; Kim, Soomin; Kim, Pyunghwa; Park, Jinhyuk; Choi, Seung-Bok

    2015-06-01

    In this study, we developed a novel four-degrees-of-freedom haptic master using controllable magnetorheological (MR) fluid. We also integrated the haptic master with a vision device with image processing for robot-assisted minimally invasive surgery (RMIS). The proposed master can be used in RMIS as a haptic interface to provide the surgeon with a sense of touch by using both kinetic and kinesthetic information. The slave robot, which is manipulated with a proportional-integrative-derivative controller, uses a force sensor to obtain the desired forces from tissue contact, and these desired repulsive forces are then embodied through the MR haptic master. To verify the effectiveness of the haptic master, the desired force and actual force are compared in the time domain. In addition, a visual feedback system is implemented in the RMIS experiment to distinguish between the tumor and organ more clearly and provide better visibility to the operator. The hue-saturation-value color space is adopted for the image processing since it is often more intuitive than other color spaces. The image processing and haptic feedback are realized on surgery performance. In this work, tumor-cutting experiments are conducted under four different operating conditions: haptic feedback on, haptic feedback off, image processing on, and image processing off. The experimental realization shows that the performance index, which is a function of pixels, is different in the four operating conditions.

  13. Interactive balance training integrating sensor-based visual feedback of movement performance: a pilot study in older adults.

    Science.gov (United States)

    Schwenk, Michael; Grewal, Gurtej S; Honarvar, Bahareh; Schwenk, Stefanie; Mohler, Jane; Khalsa, Dharma S; Najafi, Bijan

    2014-12-13

    Wearable sensor technology can accurately measure body motion and provide incentive feedback during exercising. The aim of this pilot study was to evaluate the effectiveness and user experience of a balance training program in older adults integrating data from wearable sensors into a human-computer interface designed for interactive training. Senior living community residents (mean age 84.6) with confirmed fall risk were randomized to an intervention (IG, n = 17) or control group (CG, n = 16). The IG underwent 4 weeks (twice a week) of balance training including weight shifting and virtual obstacle crossing tasks with visual/auditory real-time joint movement feedback using wearable sensors. The CG received no intervention. Outcome measures included changes in center of mass (CoM) sway, ankle and hip joint sway measured during eyes open (EO) and eyes closed (EC) balance test at baseline and post-intervention. Ankle-hip postural coordination was quantified by a reciprocal compensatory index (RCI). Physical performance was quantified by the Alternate-Step-Test (AST), Timed-up-and-go (TUG), and gait assessment. User experience was measured by a standardized questionnaire. After the intervention sway of CoM, hip, and ankle were reduced in the IG compared to the CG during both EO and EC condition (p = .007-.042). Improvement was obtained for AST (p = .037), TUG (p = .024), fast gait speed (p = . 010), but not normal gait speed (p = .264). Effect sizes were moderate for all outcomes. RCI did not change significantly. Users expressed a positive training experience including fun, safety, and helpfulness of sensor-feedback. Results of this proof-of-concept study suggest that older adults at risk of falling can benefit from the balance training program. Study findings may help to inform future exercise interventions integrating wearable sensors for guided game-based training in home- and community environments. Future studies should evaluate the

  14. Visual feedback alters force control and functional activity in the visuomotor network after stroke

    Directory of Open Access Journals (Sweden)

    Derek B. Archer

    2018-01-01

    Full Text Available Modulating visual feedback may be a viable option to improve motor function after stroke, but the neurophysiological basis for this improvement is not clear. Visual gain can be manipulated by increasing or decreasing the spatial amplitude of an error signal. Here, we combined a unilateral visually guided grip force task with functional MRI to understand how changes in the gain of visual feedback alter brain activity in the chronic phase after stroke. Analyses focused on brain activation when force was produced by the most impaired hand of the stroke group as compared to the non-dominant hand of the control group. Our experiment produced three novel results. First, gain-related improvements in force control were associated with an increase in activity in many regions within the visuomotor network in both the stroke and control groups. These regions include the extrastriate visual cortex, inferior parietal lobule, ventral premotor cortex, cerebellum, and supplementary motor area. Second, the stroke group showed gain-related increases in activity in additional regions of lobules VI and VIIb of the ipsilateral cerebellum. Third, relative to the control group, the stroke group showed increased activity in the ipsilateral primary motor cortex, and activity in this region did not vary as a function of visual feedback gain. The visuomotor network, cerebellum, and ipsilateral primary motor cortex have each been targeted in rehabilitation interventions after stroke. Our observations provide new insight into the role these regions play in processing visual gain during a precisely controlled visuomotor task in the chronic phase after stroke.

  15. 10 CFR 850.40 - Performance feedback.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Performance feedback. 850.40 Section 850.40 Energy... Performance feedback. (a) The responsible employer must conduct periodic analyses and assessments of... the line managers, planners, worker protection staff, workers, medical staff, and labor organizations...

  16. Haptically facilitated bimanual training combined with augmented visual feedback in moderate to severe hemiplegia.

    Science.gov (United States)

    Boos, Amy; Qiu, Qinyin; Fluet, Gerard G; Adamovich, Sergei V

    2011-01-01

    This study describes the design and feasibility testing of a hand rehabilitation system that provides haptic assistance for hand opening in moderate to severe hemiplegia while subjects attempt to perform bilateral hand movements. A cable-actuated exoskeleton robot assists the subjects in performing impaired finger movements but is controlled by movement of the unimpaired hand. In an attempt to combine the neurophysiological stimuli of bilateral movement and action observation during training, visual feedback of the impaired hand is replaced by feedback of the unimpaired hand, either by using a sagittaly oriented mirror or a virtual reality setup with a pair of virtual hands presented on a flat screen controlled with movement of the unimpaired hand, providing a visual image of their paretic hand moving normally. Joint angles for both hands are measured using data gloves. The system is programmed to maintain a symmetrical relationship between the two hands as they respond to commands to open and close simultaneously. Three persons with moderate to severe hemiplegia secondary to stroke trained with the system for eight, 30 to 60 minute sessions without adverse events. Each demonstrated positive motor adaptations to training. The system was well tolerated by persons with moderate to severe upper extremity hemiplegia. Further testing of its effects on motor ability with a broader range of clinical presentations is indicated.

  17. A real-time articulatory visual feedback approach with target presentation for second language pronunciation learning.

    Science.gov (United States)

    Suemitsu, Atsuo; Dang, Jianwu; Ito, Takayuki; Tiede, Mark

    2015-10-01

    Articulatory information can support learning or remediating pronunciation of a second language (L2). This paper describes an electromagnetic articulometer-based visual-feedback approach using an articulatory target presented in real-time to facilitate L2 pronunciation learning. This approach trains learners to adjust articulatory positions to match targets for a L2 vowel estimated from productions of vowels that overlap in both L1 and L2. Training of Japanese learners for the American English vowel /æ/ that included visual training improved its pronunciation regardless of whether audio training was also included. Articulatory visual feedback is shown to be an effective method for facilitating L2 pronunciation learning.

  18. The Effects of Task Clarification, Visual Prompts, and Graphic Feedback on Customer Greeting and Up-Selling in a Restaurant

    Science.gov (United States)

    Squires, James; Wilder, David A.; Fixsen, Amanda; Hess, Erica; Rost, Kristen; Curran, Ryan; Zonneveld, Kimberly

    2007-01-01

    An intervention consisting of task clarification, visual prompts, and graphic feedback was evaluated to increase customer greeting and up-selling in a restaurant. A combination multiple baseline and reversal design was used to evaluate intervention effects. Although all interventions improved performance over baseline, the delivery of graphic…

  19. Randomized crossover trial of a pressure sensing visual feedback system to improve mask fitting in noninvasive ventilation.

    Science.gov (United States)

    Brill, Anne-Kathrin; Moghal, Mohammad; Morrell, Mary J; Simonds, Anita K

    2017-10-01

    A good mask fit, avoiding air leaks and pressure effects on the skin are key elements for a successful noninvasive ventilation (NIV). However, delivering practical training for NIV is challenging, and it takes time to build experience and competency. This study investigated whether a pressure sensing system with real-time visual feedback improved mask fitting. During an NIV training session, 30 healthcare professionals (14 trained in mask fitting and 16 untrained) performed two mask fittings on the same healthy volunteer in a randomized order: one using standard mask-fitting procedures and one with additional visual feedback on mask pressure on the nasal bridge. Participants were required to achieve a mask fit with low mask pressure and minimal air leak (mask fit and staff- confidence were measured. Compared with standard mask fitting, a lower pressure was exerted on the nasal bridge using the feedback system (71.1 ± 17.6 mm Hg vs 63.2 ± 14.6 mm Hg, P mask-fitting training, resulted in a lower pressure on the skin and better mask fit for the volunteer, with increased staff confidence. © 2017 Asian Pacific Society of Respirology.

  20. Promoting Increased Pitch Variation in Oral Presentations with Transient Visual Feedback

    Directory of Open Access Journals (Sweden)

    Rebecca Hincks

    2009-10-01

    Full Text Available This paper investigates learner response to a novel kind of intonation feedback generated from speech analysis. Instead of displays of pitch curves, our feedback is flashing lights that show how much pitch variation the speaker has produced. The variable used to generate the feedback is the standard deviation of fundamental frequency as measured in semitones. Flat speech causes the system to show yellow lights, while more expressive speech that has used pitch to give focus to any part of an utterance generates green lights. Participants in the study were 14 Chinese students of English at intermediate and advanced levels. A group that received visual feedback was compared with a group that received audio feedback. Pitch variation was measured at four stages: in a baseline oral presentation; for the first and second halves of three hours of training; and finally in the production of a new oral presentation. Both groups increased their pitch variation with training, and the effect lasted after the training had ended. The test group showed a significantly higher increase than the control group, indicating that the feedback is effective. These positive results imply that the feedback could be beneficially used in a system for practicing oral presentations.

  1. A new visual feedback-based magnetorheological haptic master for robot-assisted minimally invasive surgery

    International Nuclear Information System (INIS)

    Choi, Seung-Hyun; Kim, Soomin; Kim, Pyunghwa; Park, Jinhyuk; Choi, Seung-Bok

    2015-01-01

    In this study, we developed a novel four-degrees-of-freedom haptic master using controllable magnetorheological (MR) fluid. We also integrated the haptic master with a vision device with image processing for robot-assisted minimally invasive surgery (RMIS). The proposed master can be used in RMIS as a haptic interface to provide the surgeon with a sense of touch by using both kinetic and kinesthetic information. The slave robot, which is manipulated with a proportional-integrative-derivative controller, uses a force sensor to obtain the desired forces from tissue contact, and these desired repulsive forces are then embodied through the MR haptic master. To verify the effectiveness of the haptic master, the desired force and actual force are compared in the time domain. In addition, a visual feedback system is implemented in the RMIS experiment to distinguish between the tumor and organ more clearly and provide better visibility to the operator. The hue-saturation-value color space is adopted for the image processing since it is often more intuitive than other color spaces. The image processing and haptic feedback are realized on surgery performance. In this work, tumor-cutting experiments are conducted under four different operating conditions: haptic feedback on, haptic feedback off, image processing on, and image processing off. The experimental realization shows that the performance index, which is a function of pixels, is different in the four operating conditions. (paper)

  2. Improving motor performance without training: the effect of combining mirror visual feedback with transcranial direct current stimulation.

    Science.gov (United States)

    von Rein, Erik; Hoff, Maike; Kaminski, Elisabeth; Sehm, Bernhard; Steele, Christopher J; Villringer, Arno; Ragert, Patrick

    2015-04-01

    Mirror visual feedback (MVF) during motor training has been shown to improve motor performance of the untrained hand. Here we thought to determine if MVF-induced performance improvements of the left hand can be augmented by upregulating plasticity in right primary motor cortex (M1) by means of anodal transcranial direct current stimulation (a-tDCS) while subjects trained with the right hand. Participants performed a ball-rotation task with either their left (untrained) or right (trained) hand on two consecutive days (days 1 and 2). During training with the right hand, MVF was provided concurrent with two tDCS conditions: group 1 received a-tDCS over right M1 (n = 10), whereas group 2 received sham tDCS (s-tDCS, n = 10). On day 2, performance was reevaluated under the same experimental conditions compared with day 1 but without tDCS. While baseline performance of the left hand (day 1) was not different between groups, a-tDCS exhibited stronger MVF-induced performance improvements compared with s-tDCS. Similar results were observed for day 2 (without tDCS application). A control experiment (n = 8) with a-tDCS over right M1 as outlined above but without MVF revealed that left hand improvement was significantly less pronounced than that induced by combined a-tDCS and MVF. Based on these results, we provide novel evidence that upregulating activity in the untrained M1 by means of a-tDCS is capable of augmenting MVF-induced performance improvements in young normal volunteers. Our findings suggest that concurrent MVF and tDCS might have synergistic and additive effects on motor performance of the untrained hand, a result of relevance for clinical approaches in neurorehabilitation and/or exercise science. Copyright © 2015 the American Physiological Society.

  3. Virtual environment to evaluate multimodal feedback strategies for augmented navigation of the visually impaired.

    Science.gov (United States)

    Hara, Masayuki; Shokur, Solaiman; Yamamoto, Akio; Higuchi, Toshiro; Gassert, Roger; Bleuler, Hannes

    2010-01-01

    This paper proposes a novel experimental environment to evaluate multimodal feedback strategies for augmented navigation of the visually impaired. The environment consists of virtual obstacles and walls, an optical tracking system and a simple device with audio and vibrotactile feedback that interacts with the virtual environment, and presents many advantages in terms of safety, flexibility, control over experimental parameters and cost. The subject can freely move in an empty room, while the position of head and arm are tracked in real time. A virtual environment (walls, obstacles) is randomly generated, and audio and vibrotactile feedback are given according to the distance from the subjects arm to the virtual walls/objects. We investigate the applicability of our environment using a simple, commercially available feedback device. Experiments with unimpaired subjects show that it is possible to use the setup to "blindly" navigate in an unpredictable virtual environment. This validates the environment as a test platform to investigate navigation and exploration strategies of the visually impaired, and to evaluate novel technologies for augmented navigation.

  4. Breath-hold monitoring and visual feedback for radiotherapy using a charge-coupled device camera and a head-mounted display. System development and feasibility

    International Nuclear Information System (INIS)

    Yoshitake, Tadamasa; Nakamura, Katsumasa; Shioyama, Yoshiyuki

    2008-01-01

    The aim of this study was to present the technical aspects of the breath-hold technique with respiratory monitoring and visual feedback and to evaluate the feasibility of this system in healthy volunteers. To monitor respiration, the vertical position of the fiducial marker placed on the patient's abdomen was tracked by a machine vision system with a charge-coupled device camera. A monocular head-mounted display was used to provide the patient with visual feedback about the breathing trace. Five healthy male volunteers were enrolled in this study. They held their breath at the end-inspiration and the end-expiration phases. They performed five repetitions of the same type of 15-s breath-holds with and without a head-mounted display, respectively. A standard deviation of five mean positions of the fiducial marker during a 15-s breath-hold in each breath-hold type was used as the reproducibility value of breath-hold. All five volunteers well tolerated the breath-hold maneuver. For the inspiration breath-hold, the standard deviations with and without visual feedback were 1.74 mm and 0.84 mm, respectively (P=0.20). For the expiration breath-hold, the standard deviations with and without visual feedback were 0.63 mm and 0.96 mm, respectively (P=0.025). Our newly developed system might help the patient achieve improved breath-hold reproducibility. (author)

  5. Can Performance Feedback during Instruction Boost Knowledge Acquisition? Contrasting Criterion-Based and Social Comparison Feedback

    Science.gov (United States)

    Kollöffel, Bas; de Jong, Ton

    2016-01-01

    Feedback indicating how well students are performing during a learning task can be very stimulating. In this study with a pre- and post-test design, the effects of two types of performance feedback on learning results were compared: feedback during a learning task was either stated in terms of how well the students were performing relative to…

  6. Sensorimotor Learning of Acupuncture Needle Manipulation Using Visual Feedback.

    Directory of Open Access Journals (Sweden)

    Won-Mo Jung

    Full Text Available Humans can acquire a wide variety of motor skills using sensory feedback pertaining to discrepancies between intended and actual movements. Acupuncture needle manipulation involves sophisticated hand movements and represents a fundamental skill for acupuncturists. We investigated whether untrained students could improve their motor performance during acupuncture needle manipulation using visual feedback (VF.Twenty-one untrained medical students were included, randomly divided into concurrent (n = 10 and post-trial (n = 11 VF groups. Both groups were trained in simple lift/thrusting techniques during session 1, and in complicated lift/thrusting techniques in session 2 (eight training trials per session. We compared the motion patterns and error magnitudes of pre- and post-training tests.During motion pattern analysis, both the concurrent and post-trial VF groups exhibited greater improvements in motion patterns during the complicated lifting/thrusting session. In the magnitude error analysis, both groups also exhibited reduced error magnitudes during the simple lifting/thrusting session. For the training period, the concurrent VF group exhibited reduced error magnitudes across all training trials, whereas the post-trial VF group was characterized by greater error magnitudes during initial trials, which gradually reduced during later trials.Our findings suggest that novices can improve the sophisticated hand movements required for acupuncture needle manipulation using sensorimotor learning with VF. Use of two types of VF can be beneficial for untrained students in terms of learning how to manipulate acupuncture needles, using either automatic or cognitive processes.

  7. Enhance students’ motivation to learn programming by using direct visual feed-back

    DEFF Research Database (Denmark)

    Kofoed, Lise B.; Reng, Lars

    2011-01-01

    The technical subjects chosen are within programming. Using image-processing algorithms as means to provide direct visual feedback for learning basic C/C++. The pedagogical approach is within a PBL framework and is based on dialogue and collaborative learning. At the same time the intention...... was to establish a community of practice among the students and the teachers. A direct visual feedback and a higher level of merging between the artistic, creative, and technical lectures have been the focus of motivation as well as a complete restructuring of the elements of the technical lectures. The paper...... abilities and enhanced balance between the interdisciplinary disciplines of the study are analyzed. The conclusion is that the technical courses have got a higher status for the students. The students now see it as a very important basis for their further study, and their learning results have improved...

  8. 5 CFR 9701.407 - Monitoring performance and providing feedback.

    Science.gov (United States)

    2010-01-01

    ... feedback. 9701.407 Section 9701.407 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN... performance and providing feedback. In applying the requirements of the performance management system and its... organization; and (b) Provide timely periodic feedback to employees on their actual performance with respect to...

  9. Self-esteem, performance feedback, and cardiovascular stress reactivity.

    Science.gov (United States)

    Hughes, Brian M

    2007-09-01

    This study sought to establish the impact of performance-related feedback on cardiovascular responses to stressors, and whether this impact is influenced by individual differences in self-esteem. A total of 66 college women were categorized as either high or low in self-esteem on the basis of their scores in a standardized psychometric test. They then took part in a laboratory experiment, in which they were assigned to one of three performance-feedback manipulations. Following the provision of feedback on an initial laboratory task (picture-matching), they undertook a second task (mental arithmetic). Cardiovascular functioning was monitored throughout. Provision of negative feedback to the initial task exerted an adverse impact on cardiovascular responses, suggestive of unhappiness with performance. Provision of positive feedback to the initial task exerted an impact on cardiovascular functioning during the second task, suggestive of task engagement. Importantly, low self-esteem exacerbated the adverse impact of negative feedback. The impact of feedback and the buffering role of self-esteem may have important consequences for cardiovascular health. Further, discrepancies in the findings of previous feedback research may be accounted for by dispositional individual differences.

  10. Effect of visual feedback on the occipito-parietal-motor network in Parkinson's disease patients with freezing of gait

    Directory of Open Access Journals (Sweden)

    Priya D Velu

    2014-01-01

    Full Text Available Freezing of gait (FOG is an elusive phenomenon that debilitates a large number of Parkinson’s disease (PD patients regardless of stage of disease, medication status, or DBS implantation. Sensory cues, especially visual feedback cues, have been shown to alleviate FOG episodes or prevent episodes from even occurring. Here, we examine cortical information flow between occipital, parietal, and motor areas during the pre-movement stage of gait in a PD-with-FOG patient that had a strong positive behavioral response to visual cues, a PD-with-FOG patient without any behavioral response to visual cues, and an age-matched healthy control, before and after training with visual feedback. Results for this case study show differences in cortical information flow between the responding PD-with-FOG patient and the other two subjects, notably, an increased information flow in the beta range. Tentatively suggesting the formation of an alternative cortical sensory-motor pathway during training with visual feedback, these results are proposed as subject for further verification employing larger cohorts of patients.

  11. Can performance feedback during instruction boost knowledge acquisition? Contrasting criterion-based and social comparison feedback

    NARCIS (Netherlands)

    Kolloffel, Bas Jan; de Jong, Anthonius J.M.

    2016-01-01

    Feedback indicating how well students are performing during a learning task can be very stimulating. In this study with a pre- and post-test design, the effects of two types of performance feedback on learning results were compared: feedback during a learning task was either stated in terms of how

  12. Performance Measure as Feedback Variable in Image Processing

    Directory of Open Access Journals (Sweden)

    Ristić Danijela

    2006-01-01

    Full Text Available This paper extends the view of image processing performance measure presenting the use of this measure as an actual value in a feedback structure. The idea behind is that the control loop, which is built in that way, drives the actual feedback value to a given set point. Since the performance measure depends explicitly on the application, the inclusion of feedback structures and choice of appropriate feedback variables are presented on example of optical character recognition in industrial application. Metrics for quantification of performance at different image processing levels are discussed. The issues that those metrics should address from both image processing and control point of view are considered. The performance measures of individual processing algorithms that form a character recognition system are determined with respect to the overall system performance.

  13. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model.

    Science.gov (United States)

    Li, Min; Konstantinova, Jelizaveta; Xu, Guanghua; He, Bo; Aminzadeh, Vahid; Xie, Jun; Wurdemann, Helge; Althoefer, Kaspar

    2017-01-01

    Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by sliding indentation palpation is proposed, validated, and compared with force feedback involving human subjects. In an experimental tele-manipulation environment, a dynamically updated color map depicting the stiffness of probed soft tissue is presented via a graphical interface. The force feedback is provided, aided by a master haptic device. The haptic device uses data acquired from an F/T sensor attached to the end-effector of a tele-manipulated robot. Hard nodule detection performance is evaluated for 2 modes (force feedback and visual stiffness feedback) of stiffness feedback on an artificial organ containing buried stiff nodules. From this artificial organ, a virtual-environment tissue model is generated based on sliding indentation measurements. Employing this virtual-environment tissue model, we compare the performance of human participants in distinguishing differently sized hard nodules by force feedback and visual stiffness feedback. Results indicate that the proposed distributed visual representation of tissue stiffness can be used effectively for hard nodule identification. The representation can also be used as a sufficient substitute for force feedback in tissue palpation.

  14. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model.

    Directory of Open Access Journals (Sweden)

    Min Li

    Full Text Available Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by sliding indentation palpation is proposed, validated, and compared with force feedback involving human subjects. In an experimental tele-manipulation environment, a dynamically updated color map depicting the stiffness of probed soft tissue is presented via a graphical interface. The force feedback is provided, aided by a master haptic device. The haptic device uses data acquired from an F/T sensor attached to the end-effector of a tele-manipulated robot. Hard nodule detection performance is evaluated for 2 modes (force feedback and visual stiffness feedback of stiffness feedback on an artificial organ containing buried stiff nodules. From this artificial organ, a virtual-environment tissue model is generated based on sliding indentation measurements. Employing this virtual-environment tissue model, we compare the performance of human participants in distinguishing differently sized hard nodules by force feedback and visual stiffness feedback. Results indicate that the proposed distributed visual representation of tissue stiffness can be used effectively for hard nodule identification. The representation can also be used as a sufficient substitute for force feedback in tissue palpation.

  15. Evaluation of Augmented Reality Feedback in Surgical Training Environment.

    Science.gov (United States)

    Zahiri, Mohsen; Nelson, Carl A; Oleynikov, Dmitry; Siu, Ka-Chun

    2018-02-01

    Providing computer-based laparoscopic surgical training has several advantages that enhance the training process. Self-evaluation and real-time performance feedback are 2 of these advantages, which avoid dependency of trainees on expert feedback. The goal of this study was to investigate the use of a visual time indicator as real-time feedback correlated with the laparoscopic surgical training. Twenty novices participated in this study working with (and without) different presentations of time indicators. They performed a standard peg transfer task, and their completion times and muscle activity were recorded and compared. Also of interest was whether the use of this type of feedback induced any side effect in terms of motivation or muscle fatigue. Of the 20 participants, 15 (75%) preferred using a time indicator in the training process rather than having no feedback. However, time to task completion showed no significant difference in performance with the time indicator; furthermore, no significant differences in muscle activity or muscle fatigue were detected with/without time feedback. The absence of significant difference between task performance with/without time feedback shows that using visual real-time feedback can be included in surgical training based on user preference. Trainees may benefit from this type of feedback in the form of increased motivation. The extent to which this can influence training frequency leading to performance improvement is a question for further study.

  16. Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand.

    Science.gov (United States)

    Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

    2014-01-01

    Previous research (Whitwell et al. in Exp Brain Res 188:603-611, 2008; Whitwell and Goodale in Exp Brain Res 194:619-629, 2009) has shown that trial history, but not anticipatory knowledge about the presence or absence of visual feedback on an upcoming trial, plays a vital role in determining how that feedback is exploited when grasping with the right hand. Nothing is known about how the non-dominant left hand behaves under the same feedback regimens. In present study, therefore, we compared peak grip aperture (PGA) for left- and right-hand grasps executed with and without visual feedback (i.e., closed- vs. open-loop conditions) in right-handed individuals under three different trial schedules: the feedback conditions were blocked separately, they were randomly interleaved, or they were alternated. When feedback conditions were blocked, the PGA was much larger for open-loop trials as compared to closed-loop trials, although this difference was more pronounced for right-hand grasps than left-hand grasps. Like Whitwell et al., we found that mixing open- and closed-loop trials together, compared to blocking them separately, homogenized the PGA for open- and closed-loop grasping in the right hand (i.e., the PGAs became smaller on open-loop trials and larger on closed-loop trials). In addition, the PGAs for right-hand grasps were entirely determined by trial history and not by knowledge of whether or not visual feedback would be available on an upcoming trial. In contrast to grasps made with the right hand, grasps made by the left hand were affected both by trial history and by anticipatory knowledge of the upcoming visual feedback condition. But these effects were observed only on closed-loop trials, i.e., the PGAs of grasps made with the left hand on closed-loop trials were smaller when participants could anticipate the availability of feedback on an upcoming trial (alternating trials) than when they could not (randomized trials). In contrast, grasps made with the

  17. Immediate Feedback on Accuracy and Performance: The Effects of Wireless Technology on Food Safety Tracking at a Distribution Center

    Science.gov (United States)

    Goomas, David T.

    2012-01-01

    The effects of wireless ring scanners, which provided immediate auditory and visual feedback, were evaluated to increase the performance and accuracy of order selectors at a meat distribution center. The scanners not only increased performance and accuracy compared to paper pick sheets, but were also instrumental in immediate and accurate data…

  18. Changes in Pain Modulation Occur Soon After Whiplash Trauma but are not Related to Altered Perception of Distorted Visual Feedback.

    Science.gov (United States)

    Daenen, Liesbeth; Nijs, Jo; Cras, Patrick; Wouters, Kristien; Roussel, Nathalie

    2014-09-01

    Widespread sensory hypersensitivity has been observed in acute whiplash associated disorders (WAD). Changes in descending pain modulation take part in central sensitization. However, endogenous pain modulation has never been investigated in acute WAD. Altered perception of distorted visual feedback has been observed in WAD. Both mechanisms (ie, pain modulation and perception of distorted visual feedback) may be different components of one integrated system orchestrated by the brain. This study evaluated conditioned pain modulation (CPM) in acute WAD. Secondly, we investigated whether changes in CPM are associated with altered perception of distorted visual feedback. Thirty patients with acute WAD, 35 patients with chronic WAD and 31 controls were subjected to an experiment evaluating CPM and a coordination task inducing visual mediated changes between sensory feedback and motor output. A significant CPM effect was observed in acute WAD (P = 0.012 and P = 0.006), which was significantly lower compared to controls (P = 0.004 and P = 0.020). No obvious differences in CPM were found between acute and chronic WAD (P = 0.098 and P = 0.041). Changes in CPM were unrelated to altered perception of distorted visual feedback (P > 0.01). Changes in CPM were observed in acute WAD, suggesting less efficient pain modulation. The results suggest that central pain and sensorimotor processing underlie distinctive mechanisms. © 2013 World Institute of Pain.

  19. A virtual reality-based method of decreasing transmission time of visual feedback for a tele-operative robotic catheter operating system.

    Science.gov (United States)

    Guo, Jin; Guo, Shuxiang; Tamiya, Takashi; Hirata, Hideyuki; Ishihara, Hidenori

    2016-03-01

    An Internet-based tele-operative robotic catheter operating system was designed for vascular interventional surgery, to afford unskilled surgeons the opportunity to learn basic catheter/guidewire skills, while allowing experienced physicians to perform surgeries cooperatively. Remote surgical procedures, limited by variable transmission times for visual feedback, have been associated with deterioration in operability and vascular wall damage during surgery. At the patient's location, the catheter shape/position was detected in real time and converted into three-dimensional coordinates in a world coordinate system. At the operation location, the catheter shape was reconstructed in a virtual-reality environment, based on the coordinates received. The data volume reduction significantly reduced visual feedback transmission times. Remote transmission experiments, conducted over inter-country distances, demonstrated the improved performance of the proposed prototype. The maximum error for the catheter shape reconstruction was 0.93 mm and the transmission time was reduced considerably. The results were positive and demonstrate the feasibility of remote surgery using conventional network infrastructures. Copyright © 2015 John Wiley & Sons, Ltd.

  20. A dual visual-local feedback model of the vergence eye movement system

    NARCIS (Netherlands)

    Erkelens, C.J.

    2011-01-01

    Pure vergence movements are the eye movements that we make when we change our binocular fixation between targets differing in distance but not in direction relative to the head. Pure vergence is slow and controlled by visual feedback. Saccades are the rapid eye movements that we make between targets

  1. Integrating sentiment analysis and term associations with geo-temporal visualizations on customer feedback streams

    Science.gov (United States)

    Hao, Ming; Rohrdantz, Christian; Janetzko, Halldór; Keim, Daniel; Dayal, Umeshwar; Haug, Lars-Erik; Hsu, Mei-Chun

    2012-01-01

    Twitter currently receives over 190 million tweets (small text-based Web posts) and manufacturing companies receive over 10 thousand web product surveys a day, in which people share their thoughts regarding a wide range of products and their features. A large number of tweets and customer surveys include opinions about products and services. However, with Twitter being a relatively new phenomenon, these tweets are underutilized as a source for determining customer sentiments. To explore high-volume customer feedback streams, we integrate three time series-based visual analysis techniques: (1) feature-based sentiment analysis that extracts, measures, and maps customer feedback; (2) a novel idea of term associations that identify attributes, verbs, and adjectives frequently occurring together; and (3) new pixel cell-based sentiment calendars, geo-temporal map visualizations and self-organizing maps to identify co-occurring and influential opinions. We have combined these techniques into a well-fitted solution for an effective analysis of large customer feedback streams such as for movie reviews (e.g., Kung-Fu Panda) or web surveys (buyers).

  2. Thoracic ROM measurement system with visual bio-feedback: system design and biofeedback evaluation.

    Science.gov (United States)

    Ando, Takeshi; Kawamura, Kazuya; Fujitani, Junko; Koike, Tomokazu; Fujimoto, Masashi; Fujie, Masakatsu G

    2011-01-01

    Patients with diseases such as chronic obstructive pulmonary disease (COPD) need to improve their thorax mobility. Thoracic ROM is one of the simplest and most useful indexes to evaluate the respiratory function. In this paper, we have proposed the prototype of a simple thoracic ROM measurement system with real-time visual bio-feedback in the chest expansion test. In this system, the thoracic ROM is measured using a wire-type linear encoder whose wire is wrapped around the thorax. In this paper, firstly, the repeatability and reliability of measured thoracic ROM was confirmed as a first report of the developed prototype. Secondly, we analyzed the effect of the bio-feedback system on the respiratory function. The result of the experiment showed that it was easier to maintain a large and stable thoracic ROM during deep breathing by using the real-time visual biofeedback system of the thoracic ROM.

  3. Design and test of a Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during training of upper limb movement.

    Science.gov (United States)

    Simonsen, Daniel; Popovic, Mirjana B; Spaich, Erika G; Andersen, Ole Kæseler

    2017-11-01

    The present paper describes the design and test of a low-cost Microsoft Kinect-based system for delivering adaptive visual feedback to stroke patients during the execution of an upper limb exercise. Eleven sub-acute stroke patients with varying degrees of upper limb function were recruited. Each subject participated in a control session (repeated twice) and a feedback session (repeated twice). In each session, the subjects were presented with a rectangular pattern displayed on a vertical mounted monitor embedded in the table in front of the patient. The subjects were asked to move a marker inside the rectangular pattern by using their most affected hand. During the feedback session, the thickness of the rectangular pattern was changed according to the performance of the subject, and the color of the marker changed according to its position, thereby guiding the subject's movements. In the control session, the thickness of the rectangular pattern and the color of the marker did not change. The results showed that the movement similarity and smoothness was higher in the feedback session than in the control session while the duration of the movement was longer. The present study showed that adaptive visual feedback delivered by use of the Kinect sensor can increase the similarity and smoothness of upper limb movement in stroke patients.

  4. Writing Helpful Feedback: The Influence of Feedback Type on Students' Perceptions and Writing Performance

    Directory of Open Access Journals (Sweden)

    Alyssa Taylor

    2011-12-01

    Full Text Available Written feedback on students’ assignments is a common method that instructors and teaching assistants use to inform students about their performance or guide revisions. Despite its frequency of use, written feedback often lacks sufficient detail to be beneficial to students, and additional empirical research should examine its effectiveness as a teaching tool. The current study examined the effectiveness of two different types of feedback, developed and undeveloped, in terms of its influence on students’ subsequent writing performance and students’ perceptions of the feedback. Results demonstrated that the type of feedback significantly affected students’ perceptions, with developed feedback related to higher ratings of fairness and helpfulness; however, this feedback did not have a significant positive effect on students’ written performance.Les commentaires écrits sur les travaux sont une méthode courante utilisée par les enseignants et les aides-enseignants pour renseigner les étudiants sur leurs performances ou pour orienter les révisions. Malgré leur fréquence, il arrive souvent que les commentaires écrits ne soient pas assez détaillés pour être profitables aux étudiants. De plus amples recherches empiriques devraient se pencher sur l’efficacité de cet outil d'enseignement. La présente étude porte sur l'efficacité de différents types de commentaires élaborés et sous-élaborés; sur leur influence sur la performance écrite subséquente des étudiants et sur la perception de ces derniers à propos des commentaires. Les résultats démontrent que le type de commentaires influe significativement sur la perception des étudiants, les commentaires élaborés entraînant des évaluations supérieures en ce qui a trait à l’impartialité et à l'utilité; cependant, ces commentaires n'ont pas d'effets positifs importants sur la performance écrite des étudiants.

  5. Differential effects of absent visual feedback control on gait variability during different locomotion speeds.

    Science.gov (United States)

    Wuehr, M; Schniepp, R; Pradhan, C; Ilmberger, J; Strupp, M; Brandt, T; Jahn, K

    2013-01-01

    Healthy persons exhibit relatively small temporal and spatial gait variability when walking unimpeded. In contrast, patients with a sensory deficit (e.g., polyneuropathy) show an increased gait variability that depends on speed and is associated with an increased fall risk. The purpose of this study was to investigate the role of vision in gait stabilization by determining the effects of withdrawing visual information (eyes closed) on gait variability at different locomotion speeds. Ten healthy subjects (32.2 ± 7.9 years, 5 women) walked on a treadmill for 5-min periods at their preferred walking speed and at 20, 40, 70, and 80 % of maximal walking speed during the conditions of walking with eyes open (EO) and with eyes closed (EC). The coefficient of variation (CV) and fractal dimension (α) of the fluctuations in stride time, stride length, and base width were computed and analyzed. Withdrawing visual information increased the base width CV for all walking velocities (p < 0.001). The effects of absent visual information on CV and α of stride time and stride length were most pronounced during slow locomotion (p < 0.001) and declined during fast walking speeds. The results indicate that visual feedback control is used to stabilize the medio-lateral (i.e., base width) gait parameters at all speed sections. In contrast, sensory feedback control in the fore-aft direction (i.e., stride time and stride length) depends on speed. Sensory feedback contributes most to fore-aft gait stabilization during slow locomotion, whereas passive biomechanical mechanisms and an automated central pattern generation appear to control fast locomotion.

  6. Physician Perceptions of Performance Feedback in a Quality Improvement Activity.

    Science.gov (United States)

    Eden, Aimee R; Hansen, Elizabeth; Hagen, Michael D; Peterson, Lars E

    2017-10-01

    Physician performance and peer comparison feedback can affect physician care quality and patient outcomes. This study aimed to understand family physician perspectives of the value of performance feedback in quality improvement (QI) activities. This study analyzed American Board of Family Medicine open-ended survey data collected between 2004 and 2014 from physicians who completed a QI module that provided pre- and post-QI project individual performance data and peer comparisons. Physicians made 3480 comments in response to a question about this performance feedback, which were generally positive in nature (86%). Main themes that emerged were importance of accurate feedback data, enhanced detail in the content of feedback, and ability to customize peer comparison groups to compare performance to peers with similar patient populations or practice characteristics. Meaningful and tailored performance feedback may be an important tool for physicians to improve their care quality and should be considered an integral part of QI project design.

  7. The Impact of Middle-School Students' Feedback Choices and Performance on Their Feedback Memory

    Science.gov (United States)

    Cutumisu, Maria; Schwartz, Daniel L.

    2016-01-01

    This paper presents a novel examination of the impact of students' feedback choices and performance on their feedback memory. An empirical study was designed to collect the choices to seek critical feedback from a hundred and six Grade 8 middle-school students via Posterlet, a digital assessment game in which students design posters. Upon…

  8. Short structured feedback training is equivalent to a mechanical feedback device in two-rescuer BLS: a randomised simulation study.

    Science.gov (United States)

    Pavo, Noemi; Goliasch, Georg; Nierscher, Franz Josef; Stumpf, Dominik; Haugk, Moritz; Breckwoldt, Jan; Ruetzler, Kurt; Greif, Robert; Fischer, Henrik

    2016-05-13

    Resuscitation guidelines encourage the use of cardiopulmonary resuscitation (CPR) feedback devices implying better outcomes after sudden cardiac arrest. Whether effective continuous feedback could also be given verbally by a second rescuer ("human feedback") has not been investigated yet. We, therefore, compared the effect of human feedback to a CPR feedback device. In an open, prospective, randomised, controlled trial, we compared CPR performance of three groups of medical students in a two-rescuer scenario. Group "sCPR" was taught standard BLS without continuous feedback, serving as control. Group "mfCPR" was taught BLS with mechanical audio-visual feedback (HeartStart MRx with Q-CPR-Technology™). Group "hfCPR" was taught standard BLS with human feedback. Afterwards, 326 medical students performed two-rescuer BLS on a manikin for 8 min. CPR quality parameters, such as "effective compression ratio" (ECR: compressions with correct hand position, depth and complete decompression multiplied by flow-time fraction), and other compression, ventilation and time-related parameters were assessed for all groups. ECR was comparable between the hfCPR and the mfCPR group (0.33 vs. 0.35, p = 0.435). The hfCPR group needed less time until starting chest compressions (2 vs. 8 s, p feedback or by using a mechanical audio-visual feedback device was similar. Further studies should investigate whether extended human feedback training could further increase CPR quality at comparable costs for training.

  9. Skill learning from kinesthetic feedback.

    Science.gov (United States)

    Pinzon, David; Vega, Roberto; Sanchez, Yerly Paola; Zheng, Bin

    2017-10-01

    It is important for a surgeon to perform surgical tasks under appropriate guidance from visual and kinesthetic feedback. However, our knowledge on kinesthetic (muscle) memory and its role in learning motor skills remains elementary. To discover the effect of exclusive kinesthetic training on kinesthetic memory in both performance and learning. In Phase 1, a total of twenty participants duplicated five 2 dimensional movements of increasing complexity via passive kinesthetic guidance, without visual or auditory stimuli. Five participants were asked to repeat the task in the Phase 2 over a period of three weeks, for a total of nine sessions. Subjects accurately recalled movement direction using kinesthetic memory, but recalling movement length was less precise. Over the nine training sessions, error occurrence dropped after the sixth session. Muscle memory constructs the foundation for kinesthetic training. Knowledge gained helps surgeons learn skills from kinesthetic information in the condition where visual feedback is limited. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. The Use of Performance Feedback in School Improvement in Louisiana

    Science.gov (United States)

    Schildkamp, Kim; Visscher, Adrie

    2010-01-01

    Although school performance feedback is available in schools all over the world, there is a dearth of information about the use made of feedback and about the effects of its use. This paper presents case study research into the use of school performance feedback and its perceived effects. All schools used the feedback in writing school improvement…

  11. Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley Ernest [National Renewable Energy Lab, 15013 Denver West Parkway, Golden, CO 80401; Sharifi, Elham [Center for Advanced Transportation Technology, University of Maryland, College Park, Technology Ventures Building, Suite 2200, 5000 College Avenue, College Park, MD 20742; Day, Christopher M. [Joint Transportation Research Program, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906; Bullock, Darcy M. [Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906

    2017-01-01

    This paper provides a visual reference of the breadth of arterial performance phenomena based on travel time measures obtained from reidentification technology that has proliferated in the past 5 years. These graphical performance measures are revealed through overlay charts and statistical distribution as revealed through cumulative frequency diagrams (CFDs). With overlays of vehicle travel times from multiple days, dominant traffic patterns over a 24-h period are reinforced and reveal the traffic behavior induced primarily by the operation of traffic control at signalized intersections. A cumulative distribution function in the statistical literature provides a method for comparing traffic patterns from various time frames or locations in a compact visual format that provides intuitive feedback on arterial performance. The CFD may be accumulated hourly, by peak periods, or by time periods specific to signal timing plans that are in effect. Combined, overlay charts and CFDs provide visual tools with which to assess the quality and consistency of traffic movement for various periods throughout the day efficiently, without sacrificing detail, which is a typical byproduct of numeric-based performance measures. These methods are particularly effective for comparing before-and-after median travel times, as well as changes in interquartile range, to assess travel time reliability.

  12. Effect of feedback on delaying deterioration in quality of compressions during 2 minutes of continuous chest compressions: a randomized manikin study investigating performance with and without feedback

    Directory of Open Access Journals (Sweden)

    Lyngeraa Tobias

    2012-02-01

    Full Text Available Abstract Background Good quality basic life support (BLS improves outcome following cardiac arrest. As BLS performance deteriorates over time we performed a parallel group, superiority study to investigate the effect of feedback on quality of chest compression with the hypothesis that feedback delays deterioration of quality of compressions. Methods Participants attending a national one-day conference on cardiac arrest and CPR in Denmark were randomized to perform single-rescuer BLS with (n = 26 or without verbal and visual feedback (n = 28 on a manikin using a ZOLL AED plus. Data were analyzed using Rescuenet Code Review. Blinding of participants was not possible, but allocation concealment was performed. Primary outcome was the proportion of delivered compressions within target depth compared over a 2-minute period within the groups and between the groups. Secondary outcome was the proportion of delivered compressions within target rate compared over a 2-minute period within the groups and between the groups. Performance variables for 30-second intervals were analyzed and compared. Results 24 (92% and 23 (82% had CPR experience in the group with and without feedback respectively. 14 (54% were CPR instructors in the feedback group and 18 (64% in the group without feedback. Data from 26 and 28 participants were analyzed respectively. Although median values for proportion of delivered compressions within target depth were higher in the feedback group (0-30 s: 54.0%; 30-60 s: 88.0%; 60-90 s: 72.6%; 90-120 s: 87.0%, no significant difference was found when compared to without feedback (0-30 s: 19.6%; 30-60 s: 33.1%; 60-90 s: 44.5%; 90-120 s: 32.7% and no significant deteriorations over time were found within the groups. In the feedback group a significant improvement was found in the proportion of delivered compressions below target depth when the subsequent intervals were compared to the first 30 seconds (0-30 s: 3.9%; 30-60 s: 0.0%; 60-90 s: 0

  13. Performance feedback, self-esteem, and cardiovascular adaptation to recurring stressors.

    Science.gov (United States)

    Brown, Eoin G; Creaven, Ann-Marie

    2017-05-01

    This study sought to examine the effects of performance feedback and individual differences in self-esteem on cardiovascular habituation to repeat stress exposure. Sixty-six university students (n = 39 female) completed a self-esteem measure and completed a cardiovascular stress-testing protocol involving repeated exposure to a mental arithmetic task. Cardiovascular functioning was sampled across four phases: resting baseline, initial stress exposure, a recovery period, and repeated stress exposure. Participants were randomly assigned to receive fictional positive feedback, negative feedback, or no feedback following the recovery period. Negative feedback was associated with a sensitized blood pressure response to a second exposure of the stress task. Positive feedback was associated with decreased cardiovascular and psychological responses to a second exposure. Self-esteem was also found to predict reactivity and this interacted with the type of feedback received. These findings suggest that negative performance feedback sensitizes cardiovascular reactivity to stress, whereas positive performance feedback increases both cardiovascular and psychological habituation to repeat exposure to stressors. Furthermore, an individual's self-esteem also appears to influence this process.

  14. Task-irrelevant auditory feedback facilitates motor performance in musicians

    Directory of Open Access Journals (Sweden)

    Virginia eConde

    2012-05-01

    Full Text Available An efficient and fast auditory–motor network is a basic resource for trained musicians due to the importance of motor anticipation of sound production in musical performance. When playing an instrument, motor performance always goes along with the production of sounds and the integration between both modalities plays an essential role in the course of musical training. The aim of the present study was to investigate the role of task-irrelevant auditory feedback during motor performance in musicians using a serial reaction time task (SRTT. Our hypothesis was that musicians, due to their extensive auditory–motor practice routine during musical training, have a superior performance and learning capabilities when receiving auditory feedback during SRTT relative to musicians performing the SRTT without any auditory feedback. Here we provide novel evidence that task-irrelevant auditory feedback is capable to reinforce SRTT performance but not learning, a finding that might provide further insight into auditory-motor integration in musicians on a behavioral level.

  15. Reliability of Visual and Somatosensory Feedback in Skilled Movement: The Role of the Cerebellum.

    Science.gov (United States)

    Mizelle, J C; Oparah, Alexis; Wheaton, Lewis A

    2016-01-01

    The integration of vision and somatosensation is required to allow for accurate motor behavior. While both sensory systems contribute to an understanding of the state of the body through continuous updating and estimation, how the brain processes unreliable sensory information remains to be fully understood in the context of complex action. Using functional brain imaging, we sought to understand the role of the cerebellum in weighting visual and somatosensory feedback by selectively reducing the reliability of each sense individually during a tool use task. We broadly hypothesized upregulated activation of the sensorimotor and cerebellar areas during movement with reduced visual reliability, and upregulated activation of occipital brain areas during movement with reduced somatosensory reliability. As specifically compared to reduced somatosensory reliability, we expected greater activations of ipsilateral sensorimotor cerebellum for intact visual and somatosensory reliability. Further, we expected that ipsilateral posterior cognitive cerebellum would be affected with reduced visual reliability. We observed that reduced visual reliability results in a trend towards the relative consolidation of sensorimotor activation and an expansion of cerebellar activation. In contrast, reduced somatosensory reliability was characterized by the absence of cerebellar activations and a trend towards the increase of right frontal, left parietofrontal activation, and temporo-occipital areas. Our findings highlight the role of the cerebellum for specific aspects of skillful motor performance. This has relevance to understanding basic aspects of brain functions underlying sensorimotor integration, and provides a greater understanding of cerebellar function in tool use motor control.

  16. Feedback Providing Improvement Strategies and Reflection on Feedback Use: Effects on Students' Writing Motivation, Process, and Performance

    Science.gov (United States)

    Duijnhouwer, Hendrien; Prins, Frans J.; Stokking, Karel M.

    2012-01-01

    This study investigated the effects of feedback providing improvement strategies and a reflection assignment on students' writing motivation, process, and performance. Students in the experimental feedback condition (n = 41) received feedback including improvement strategies, whereas students in the control feedback condition (n = 41) received…

  17. Experimental System for Investigation of Visual Sensory Input in Postural Feedback Control

    Directory of Open Access Journals (Sweden)

    Jozef Pucik

    2012-01-01

    Full Text Available The human postural control system represents a biological feedback system responsible for maintenance of upright stance. Vestibular, proprioceptive and visual sensory inputs provide the most important information into the control system, which controls body centre of mass (COM in order to stabilize the human body resembling an inverted pendulum. The COM can be measured indirectly by means of a force plate as the centre of pressure (COP. Clinically used measurement method is referred to as posturography. In this paper, the conventional static posturography is extended by visual stimulation, which provides insight into a role of visual information in balance control. Visual stimuli have been designed to induce body sway in four specific directions – forward, backward, left and right. Stabilograms were measured using proposed single-PC based system and processed to calculate velocity waveforms and posturographic parameters. The parameters extracted from pre-stimulus and on-stimulus periods exhibit statistically significant differences.

  18. Assisting the Visually Impaired: Obstacle Detection and Warning System by Acoustic Feedback

    Directory of Open Access Journals (Sweden)

    Andrés Cela

    2012-12-01

    Full Text Available The aim of this article is focused on the design of an obstacle detection system for assisting visually impaired people. A dense disparity map is computed from the images of a stereo camera carried by the user. By using the dense disparity map, potential obstacles can be detected in 3D in indoor and outdoor scenarios. A ground plane estimation algorithm based on RANSAC plus filtering techniques allows the robust detection of the ground in every frame. A polar grid representation is proposed to account for the potential obstacles in the scene. The design is completed with acoustic feedback to assist visually impaired users while approaching obstacles. Beep sounds with different frequencies and repetitions inform the user about the presence of obstacles. Audio bone conducting technology is employed to play these sounds without interrupting the visually impaired user from hearing other important sounds from its local environment. A user study participated by four visually impaired volunteers supports the proposed system.

  19. The use of performance feedback in school improvement in Louisiana

    NARCIS (Netherlands)

    Schildkamp, Kim; Visscher, Arend J.

    2010-01-01

    Although school performance feedback is available in schools all over the world, there is a dearth of information about the use made of feedback and about the effects of its use. This paper presents case study research into the use of school performance feedback and its’ perceived effects. All

  20. The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

    Science.gov (United States)

    Emmorey, Karen; Korpics, Franco; Petronio, Karen

    2009-01-01

    The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf…

  1. Use of visual CO2 feedback as a retrofit solution for improving classroom air quality

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Da Silva, Nuno Alexandre Faria

    2015-01-01

    Carbon dioxide (CO2) sensors that provide a visual indication were installed in classrooms during normal school operation. During 2-week periods, teachers and students were instructed to open the windows in response to the visual CO2 feedback in 1week and open them, as they would normally do, wit...

  2. Alpha and gamma oscillations characterize feedback and feedforward processing in monkey visual cortex.

    Science.gov (United States)

    van Kerkoerle, Timo; Self, Matthew W; Dagnino, Bruno; Gariel-Mathis, Marie-Alice; Poort, Jasper; van der Togt, Chris; Roelfsema, Pieter R

    2014-10-07

    Cognitive functions rely on the coordinated activity of neurons in many brain regions, but the interactions between cortical areas are not yet well understood. Here we investigated whether low-frequency (α) and high-frequency (γ) oscillations characterize different directions of information flow in monkey visual cortex. We recorded from all layers of the primary visual cortex (V1) and found that γ-waves are initiated in input layer 4 and propagate to the deep and superficial layers of cortex, whereas α-waves propagate in the opposite direction. Simultaneous recordings from V1 and downstream area V4 confirmed that γ- and α-waves propagate in the feedforward and feedback direction, respectively. Microstimulation in V1 elicited γ-oscillations in V4, whereas microstimulation in V4 elicited α-oscillations in V1, thus providing causal evidence for the opposite propagation of these rhythms. Furthermore, blocking NMDA receptors, thought to be involved in feedback processing, suppressed α while boosting γ. These results provide new insights into the relation between brain rhythms and cognition.

  3. Performance Feedback Processing Is Positively Biased As Predicted by Attribution Theory.

    Directory of Open Access Journals (Sweden)

    Christoph W Korn

    Full Text Available A considerable literature on attribution theory has shown that healthy individuals exhibit a positivity bias when inferring the causes of evaluative feedback on their performance. They tend to attribute positive feedback internally (e.g., to their own abilities but negative feedback externally (e.g., to environmental factors. However, all empirical demonstrations of this bias suffer from at least one of the three following drawbacks: First, participants directly judge explicit causes for their performance. Second, participants have to imagine events instead of experiencing them. Third, participants assess their performance only after receiving feedback and thus differences in baseline assessments cannot be excluded. It is therefore unclear whether the classically reported positivity bias generalizes to setups without these drawbacks. Here, we aimed at establishing the relevance of attributions for decision-making by showing an attribution-related positivity bias in a decision-making task. We developed a novel task, which allowed us to test how participants changed their evaluations in response to positive and negative feedback about performance. Specifically, we used videos of actors expressing different facial emotional expressions. Participants were first asked to evaluate the actors' credibility in expressing a particular emotion. After this initial rating, participants performed an emotion recognition task and did--or did not--receive feedback on their veridical performance. Finally, participants re-rated the actors' credibility, which provided a measure of how they changed their evaluations after feedback. Attribution theory predicts that participants change their evaluations of the actors' credibility toward the positive after receiving positive performance feedback and toward the negative after negative performance feedback. Our results were in line with this prediction. A control condition without feedback showed that correct or

  4. Performance Feedback Processing Is Positively Biased As Predicted by Attribution Theory.

    Science.gov (United States)

    Korn, Christoph W; Rosenblau, Gabriela; Rodriguez Buritica, Julia M; Heekeren, Hauke R

    2016-01-01

    A considerable literature on attribution theory has shown that healthy individuals exhibit a positivity bias when inferring the causes of evaluative feedback on their performance. They tend to attribute positive feedback internally (e.g., to their own abilities) but negative feedback externally (e.g., to environmental factors). However, all empirical demonstrations of this bias suffer from at least one of the three following drawbacks: First, participants directly judge explicit causes for their performance. Second, participants have to imagine events instead of experiencing them. Third, participants assess their performance only after receiving feedback and thus differences in baseline assessments cannot be excluded. It is therefore unclear whether the classically reported positivity bias generalizes to setups without these drawbacks. Here, we aimed at establishing the relevance of attributions for decision-making by showing an attribution-related positivity bias in a decision-making task. We developed a novel task, which allowed us to test how participants changed their evaluations in response to positive and negative feedback about performance. Specifically, we used videos of actors expressing different facial emotional expressions. Participants were first asked to evaluate the actors' credibility in expressing a particular emotion. After this initial rating, participants performed an emotion recognition task and did--or did not--receive feedback on their veridical performance. Finally, participants re-rated the actors' credibility, which provided a measure of how they changed their evaluations after feedback. Attribution theory predicts that participants change their evaluations of the actors' credibility toward the positive after receiving positive performance feedback and toward the negative after negative performance feedback. Our results were in line with this prediction. A control condition without feedback showed that correct or incorrect performance

  5. Mirror Visual Feedback Training Improves Intermanual Transfer in a Sport-Specific Task: A Comparison between Different Skill Levels

    Directory of Open Access Journals (Sweden)

    Fabian Steinberg

    2016-01-01

    Full Text Available Mirror training therapy is a promising tool to initiate neural plasticity and facilitate the recovery process of motor skills after diseases such as stroke or hemiparesis by improving the intermanual transfer of fine motor skills in healthy people as well as in patients. This study evaluated whether these augmented performance improvements by mirror visual feedback (MVF could be used for learning a sport-specific skill and if the effects are modulated by skill level. A sample of 39 young, healthy, and experienced basketball and handball players and 41 novices performed a stationary basketball dribble task at a mirror box in a standing position and received either MVF or direct feedback. After four training days using only the right hand, performance of both hands improved from pre- to posttest measurements. Only the left hand (untrained performance of the experienced participants receiving MVF was more pronounced than for the control group. This indicates that intermanual motor transfer can be improved by MVF in a sport-specific task. However, this effect cannot be generalized to motor learning per se since it is modulated by individuals’ skill level, a factor that might be considered in mirror therapy research.

  6. Adaptation effects in static postural control by providing simultaneous visual feedback of center of pressure and center of gravity.

    Science.gov (United States)

    Takeda, Kenta; Mani, Hiroki; Hasegawa, Naoya; Sato, Yuki; Tanaka, Shintaro; Maejima, Hiroshi; Asaka, Tadayoshi

    2017-07-19

    The benefit of visual feedback of the center of pressure (COP) on quiet standing is still debatable. This study aimed to investigate the adaptation effects of visual feedback training using both the COP and center of gravity (COG) during quiet standing. Thirty-four healthy young adults were divided into three groups randomly (COP + COG, COP, and control groups). A force plate was used to calculate the coordinates of the COP in the anteroposterior (COP AP ) and mediolateral (COP ML ) directions. A motion analysis system was used to calculate the coordinates of the center of mass (COM) in both directions (COM AP and COM ML ). The coordinates of the COG in the AP direction (COG AP ) were obtained from the force plate signals. Augmented visual feedback was presented on a screen in the form of fluctuation circles in the vertical direction that moved upward as the COP AP and/or COG AP moved forward and vice versa. The COP + COG group received the real-time COP AP and COG AP feedback simultaneously, whereas the COP group received the real-time COP AP feedback only. The control group received no visual feedback. In the training session, the COP + COG group was required to maintain an even distance between the COP AP and COG AP and reduce the COG AP fluctuation, whereas the COP group was required to reduce the COP AP fluctuation while standing on a foam pad. In test sessions, participants were instructed to keep their standing posture as quiet as possible on the foam pad before (pre-session) and after (post-session) the training sessions. In the post-session, the velocity and root mean square of COM AP in the COP + COG group were lower than those in the control group. In addition, the absolute value of the sum of the COP - COM distances in the COP + COG group was lower than that in the COP group. Furthermore, positive correlations were found between the COM AP velocity and COP - COM parameters. The results suggest that the novel visual feedback

  7. Neural correlates of anticipation and processing of performance feedback in social anxiety.

    Science.gov (United States)

    Heitmann, Carina Y; Peterburs, Jutta; Mothes-Lasch, Martin; Hallfarth, Marlit C; Böhme, Stephanie; Miltner, Wolfgang H R; Straube, Thomas

    2014-12-01

    Fear of negative evaluation, such as negative social performance feedback, is the core symptom of social anxiety. The present study investigated the neural correlates of anticipation and perception of social performance feedback in social anxiety. High (HSA) and low (LSA) socially anxious individuals were asked to give a speech on a personally relevant topic and received standardized but appropriate expert performance feedback in a succeeding experimental session in which neural activity was measured during anticipation and presentation of negative and positive performance feedback concerning the speech performance, or a neutral feedback-unrelated control condition. HSA compared to LSA subjects reported greater anxiety during anticipation of negative feedback. Functional magnetic resonance imaging results showed deactivation of medial prefrontal brain areas during anticipation of negative feedback relative to the control and the positive condition, and medial prefrontal and insular hyperactivation during presentation of negative as well as positive feedback in HSA compared to LSA subjects. The results indicate distinct processes underlying feedback processing during anticipation and presentation of feedback in HSA as compared to LSA individuals. In line with the role of the medial prefrontal cortex in self-referential information processing and the insula in interoception, social anxiety seems to be associated with lower self-monitoring during feedback anticipation, and an increased self-focus and interoception during feedback presentation, regardless of feedback valence. © 2014 Wiley Periodicals, Inc.

  8. Feedback providing improvement strategies and reflection on feedback use: Effects on students' writing motivation, process, and performance

    NARCIS (Netherlands)

    Duijnhouwer, H.; Prins, F.J.; Stokking, K.M.

    2012-01-01

    This study investigated the effects of feedback providing improvement strategies and a reflection assignment on students’ writing motivation, process, and performance. Students in the experimental feedback condition (n = 41) received feedback including improvement strategies, whereas students in the

  9. Real-time vision, tactile cues, and visual form agnosia in pantomimed grasping: removing haptic feedback induces a switch from natural to pantomime-like grasps

    Directory of Open Access Journals (Sweden)

    Robert Leslie Whitwell

    2015-05-01

    Full Text Available Investigators study the kinematics of grasping movements (prehension under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. When patient DF, who suffers from visual form agnosia, performs natural grasps, her in-flight hand aperture is scaled to the widths of targets ('grip scaling' that she cannot discriminate amongst. In contrast, when DF's pantomime grasps are based on a memory of a previewed object, her grip scaling is very poor. Her failure on this task has been interpreted as additional support for the dissociation between the use of object vision for action and object vision for perception. Curiously, however, when DF directs her pantomimed grasps towards a displaced imagined copy of a visible object where her fingers make contact with the surface of the table, her grip scaling does not appear to be particularly poor. In the first of two experiments, we revisit this previous work and show that her grip scaling in this real-time pantomime grasping task does not differ from controls, suggesting that terminal tactile feedback from a proxy of the target can maintain DF's grip scaling. In a second experiment with healthy participants, we tested a recent variant of a grasping task in which no tactile feedback is available (i.e. no haptic feedback by comparing the kinematics of target-directed grasps with and without haptic feedback to those of real-time pantomime grasps without haptic feedback. Compared to natural grasps, removing haptic feedback increased RT, slowed the velocity of the reach, reduced grip aperture, sharpened the slopes relating grip aperture to target width, and reduced the final grip aperture. All of these effects were also observed in the pantomime grasping task. Taken together, these results provide compelling support for the view that removing haptic feedback induces a switch from real-time visual control to one that depends more on visual perception and cognitive supervision.

  10. Guideline implementation in clinical practice: Use of statistical process control charts as visual feedback devices

    Directory of Open Access Journals (Sweden)

    Fahad A Al-Hussein

    2009-01-01

    Conclusions: A process of audits in the context of statistical process control is necessary for any improvement in the implementation of guidelines in primary care. Statistical process control charts are an effective means of visual feedback to the care providers.

  11. Environmental Feedback and Spatial Conditioning

    DEFF Research Database (Denmark)

    Foged, Isak Worre; Poulsen, Esben Skouboe

    2010-01-01

    with structural integrity, where thermal energy flow through the prototype, to be understood as a membrane, can be controlled and the visual transparancy altered. The work shows performance based feedback systems and physical prototype models driven by information streaming, screening and application....

  12. Feedforward/feedback control synthesis for performance and robustness

    Science.gov (United States)

    Wie, Bong; Liu, Qiang

    1990-01-01

    Both feedforward and feedback control approaches for uncertain dynamical systems are investigated. The control design objective is to achieve a fast settling time (high performance) and robustness (insensitivity) to plant modeling uncertainty. Preshapong of an ideal, time-optimal control input using a 'tapped-delay' filter is shown to provide a rapid maneuver with robust performance. A robust, non-minimum-phase feedback controller is synthesized with particular emphasis on its proper implementation for a non-zero set-point control problem. The proposed feedforward/feedback control approach is robust for a certain class of uncertain dynamical systems, since the control input command computed for a given desired output does not depend on the plant parameters.

  13. The Impact of feedback and incentive schemes on performance

    OpenAIRE

    Bruun-Olsen, Alexandra M.; Engelsen Eian, Camilla

    2015-01-01

    Master's thesis in Business administration In this thesis we analyze how different feedback (objective and subjective), incentive schemes (fixed pay and performance pay), and the interaction between them impact performance. To answer our research question we conduct a lab experiment on students from the University of Stavanger. The experiment consists of subjects performing a combined coloring- and calculation task over three periods and receiving either objective or subjective feedback af...

  14. Effect of biased feedback on motor imagery learning in BCI-teleoperation system

    Directory of Open Access Journals (Sweden)

    Maryam eAlimardani

    2014-04-01

    Full Text Available Feedback design is an important issue in motor imagery BCI systems. Regardless, to date it has not been reported how feedback presentation can optimize co-adaptation between a human brain and such systems. This paper assesses the effect of realistic visual feedback on users’ BC performance and motor imagery skills. We previously developed a tele-operation system for a pair of humanlike robotic hands and showed that BCI control of such hands along with first-person perspective visual feedback of movements can arouse a sense of embodiment in the operators. In the first stage of this study, we found that the intensity of this ownership illusion was associated with feedback presentation and subjects’ performance during BCI motion control. In the second stage, we probed the effect of positive and negative feedback bias on subjects’ BCI performance and motor imagery skills. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects’ online performance, evaluation of brain activity patterns revealed that subjects’ self-regulation of motor imagery features improved due to a positive bias of feedback and a possible occurrence of ownership illusion. Our findings suggest that in general training protocols for BCIs, manipulation of feedback can play an important role in the optimization of subjects’ motor imagery skills.

  15. The effect of quick feedback on employee motivation and performance : A qualitative study on how to formulate effective feedback

    OpenAIRE

    Marthouret, Eloïse; Sigvardsson, Sofie

    2016-01-01

    This thesis conceptualizes quick feedback as part of a performance management tool influencing and contributing to the individual’s self-motivation to work and improvement of employees’ performance. Prior research has shown that feedback is often considered to be a useful communication tool but not essential due to its time-consumption, i.e. feedback is perceived as too time-consuming to be prioritized. Thus, this thesis investigates the potential benefits of a quick feedback strategy focusin...

  16. The influence of visual feedback from the recent past on the programming of grip aperture is grasp-specific, shared between hands, and mediated by sensorimotor memory not task set.

    Science.gov (United States)

    Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

    2015-05-01

    Goal-directed movements, such as reaching out to grasp an object, are necessarily constrained by the spatial properties of the target such as its size, shape, and position. For example, during a reach-to-grasp movement, the peak width of the aperture formed by the thumb and fingers in flight (peak grip aperture, PGA) is linearly related to the target's size. Suppressing vision throughout the movement (visual open loop) has a small though significant effect on this relationship. Visual open loop conditions also produce a large increase in the PGA compared to when vision is available throughout the movement (visual closed loop). Curiously, this differential effect of the availability of visual feedback is influenced by the presentation order: the difference in PGA between closed- and open-loop trials is smaller when these trials are intermixed (an effect we have called 'homogenization'). Thus, grasping movements are affected not only by the availability of visual feedback (closed loop or open loop) but also by what happened on the previous trial. It is not clear, however, whether this carry-over effect is mediated through motor (or sensorimotor) memory or through the interference of different task sets for closed-loop and open-loop feedback that determine when the movements are fully specified. We reasoned that sensorimotor memory, but not a task set for closed and open loop feedback, would be specific to the type of response. We tested this prediction in a condition in which pointing to targets was alternated with grasping those same targets. Critically, in this condition, when pointing was performed in open loop, grasping was always performed in closed loop (and vice versa). Despite the fact that closed- and open-loop trials were alternating in this condition, we found no evidence for homogenization of the PGA. Homogenization did occur, however, in a follow-up experiment in which grasping movements and visual feedback were alternated between the left and the right

  17. The Role of Locus of Control and Feedback on Performance of ...

    African Journals Online (AJOL)

    This study examined Students' Locus of Control and Teacher Feedback using a 2x3 factorial to measure the performance of thirty-six (36) primary school students utilizing the two locus of control types and three levels of teacher feedback: no feedback, attributional feedback, and progressive feedback. No significant ...

  18. Evaluating User Response to In-Car Haptic Feedback Touchscreens Using the Lane Change Test

    Directory of Open Access Journals (Sweden)

    Matthew J. Pitts

    2012-01-01

    Full Text Available Touchscreen interfaces are widely used in modern technology, from mobile devices to in-car infotainment systems. However, touchscreens impose significant visual workload demands on the user which have safety implications for use in cars. Previous studies indicate that the application of haptic feedback can improve both performance of and affective response to user interfaces. This paper reports on and extends the findings of a 2009 study conducted to evaluate the effects of different combinations of touchscreen visual, audible, and haptic feedback on driving and task performance, affective response, and subjective workload; the initial findings of which were originally published in (M. J. Pitts et al., 2009. A total of 48 non-expert users completed the study. A dual-task approach was applied, using the Lane Change Test as the driving task and realistic automotive use case touchscreen tasks. Results indicated that, while feedback type had no effect on driving or task performance, preference was expressed for multimodal feedback over visual alone. Issues relating to workload and cross-modal interaction were also identified.

  19. Online visual feedback during error-free channel trials leads to active unlearning of movement dynamics: evidence for adaptation to trajectory prediction errors.

    Directory of Open Access Journals (Sweden)

    Angel Lago-Rodriguez

    2016-09-01

    Full Text Available Prolonged exposure to movement perturbations leads to creation of motor memories which decay towards previous states when the perturbations are removed. However, it remains unclear whether this decay is due only to a spontaneous and passive recovery of the previous state. It has recently been reported that activation of reinforcement-based learning mechanisms delays the onset of the decay. This raises the question whether other motor learning mechanisms may also contribute to the retention and/or decay of the motor memory. Therefore, we aimed to test whether mechanisms of error-based motor adaptation are active during the decay of the motor memory. Forty-five right-handed participants performed point-to-point reaching movements under an external dynamic perturbation. We measured the expression of the motor memory through error-clamped (EC trials, in which lateral forces constrained movements to a straight line towards the target. We found greater and faster decay of the motor memory for participants who had access to full online visual feedback during these EC trials (Cursor group, when compared with participants who had no EC feedback regarding movement trajectory (Arc group. Importantly, we did not find between-group differences in adaptation to the external perturbation. In addition, we found greater decay of the motor memory when we artificially increased feedback errors through the manipulation of visual feedback (Augmented-Error group. Our results then support the notion of an active decay of the motor memory, suggesting that adaptive mechanisms are involved in correcting for the mismatch between predicted movement trajectories and actual sensory feedback, which leads to greater and faster decay of the motor memory.

  20. Real-time modulation of visual feedback on human full-body movements in a virtual mirror: development and proof-of-concept.

    Science.gov (United States)

    Roosink, Meyke; Robitaille, Nicolas; McFadyen, Bradford J; Hébert, Luc J; Jackson, Philip L; Bouyer, Laurent J; Mercier, Catherine

    2015-01-05

    Virtual reality (VR) provides interactive multimodal sensory stimuli and biofeedback, and can be a powerful tool for physical and cognitive rehabilitation. However, existing systems have generally not implemented realistic full-body avatars and/or a scaling of visual movement feedback. We developed a "virtual mirror" that displays a realistic full-body avatar that responds to full-body movements in all movement planes in real-time, and that allows for the scaling of visual feedback on movements in real-time. The primary objective of this proof-of-concept study was to assess the ability of healthy subjects to detect scaled feedback on trunk flexion movements. The "virtual mirror" was developed by integrating motion capture, virtual reality and projection systems. A protocol was developed to provide both augmented and reduced feedback on trunk flexion movements while sitting and standing. The task required reliance on both visual and proprioceptive feedback. The ability to detect scaled feedback was assessed in healthy subjects (n = 10) using a two-alternative forced choice paradigm. Additionally, immersion in the VR environment and task adherence (flexion angles, velocity, and fluency) were assessed. The ability to detect scaled feedback could be modelled using a sigmoid curve with a high goodness of fit (R2 range 89-98%). The point of subjective equivalence was not significantly different from 0 (i.e. not shifted), indicating an unbiased perception. The just noticeable difference was 0.035 ± 0.007, indicating that subjects were able to discriminate different scaling levels consistently. VR immersion was reported to be good, despite some perceived delays between movements and VR projections. Movement kinematic analysis confirmed task adherence. The new "virtual mirror" extends existing VR systems for motor and pain rehabilitation by enabling the use of realistic full-body avatars and scaled feedback. Proof-of-concept was demonstrated for the assessment of

  1. Performance Feedback: Individual Based Reflections and the Effect on Motivation

    OpenAIRE

    Kaymaz, Kurtulus

    2011-01-01

    There is also enough scientific research proved the positive effect of performance on motivation. The common idea is that the performance feedback improve the technical and behavioral effectiveness of employees which then reflect on the job motivation. Around this idea, performance feedback effect motivation via reducing the performance ambiguity, improving the manager-subordinate relationships, making more easy to achieve goals, supporting the personal development and adapting to change. In ...

  2. The Development and Validation of a Rubric to Enhance Performer Feedback for Undergraduate Vocal Solo Performance

    Science.gov (United States)

    Herrell, Katherine A.

    2014-01-01

    This is a study of the development and validation of a rubric to enhance performer feedback for undergraduate vocal solo performance. In the literature, assessment of vocal performance is under-represented, and the value of feedback from the assessment of musical performances, from the point of view of the performer, is nonexistent. The research…

  3. A Component Analysis of the Impact of Evaluative and Objective Feedback on Performance

    Science.gov (United States)

    Johnson, Douglas A.

    2013-01-01

    Despite the frequency with which performance feedback interventions are used in organizational behavior management, component analyses of such feedback are rare. It has been suggested that evaluation of performance and objective details about performance are two necessary components for performance feedback. The present study was designed to help…

  4. Interface Prostheses With Classifier-Feedback-Based User Training.

    Science.gov (United States)

    Fang, Yinfeng; Zhou, Dalin; Li, Kairu; Liu, Honghai

    2017-11-01

    It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well as the centroids of the training samples, whose dimensionality is reduced to minimal number by dimension reduction. Clustering feedback provides a criterion that guides users to adjust motion gestures and muscle contraction forces intentionally. The experiment results have demonstrated that hand motion recognition accuracy increases steadily along the progress of the clustering-feedback-based user training, while conventional classifier-feedback methods, i.e., label feedback, hardly achieve any improvement. The result concludes that the use of proper classifier feedback can accelerate the process of user training, and implies prosperous future for the amputees with limited or no experience in pattern-recognition-based prosthetic device manipulation.It is evident that user training significantly affects performance of pattern-recognition-based myoelectric prosthetic device control. Despite plausible classification accuracy on offline datasets, online accuracy usually suffers from the changes in physiological conditions and electrode displacement. The user ability in generating consistent electromyographic (EMG) patterns can be enhanced via proper user training strategies in order to improve online performance. This study proposes a clustering-feedback strategy that provides real-time feedback to users by means of a visualized online EMG signal input as well

  5. Improving Student Performance Using Nudge Analytics

    Science.gov (United States)

    Feild, Jacqueline

    2015-01-01

    Providing students with continuous and personalized feedback on their performance is an important part of encouraging self regulated learning. As part of our higher education platform, we built a set of data visualizations to provide feedback to students on their assignment performance. These visualizations give students information about how they…

  6. A feedback model of visual attention.

    Science.gov (United States)

    Spratling, M W; Johnson, M H

    2004-03-01

    Feedback connections are a prominent feature of cortical anatomy and are likely to have a significant functional role in neural information processing. We present a neural network model of cortical feedback that successfully simulates neurophysiological data associated with attention. In this domain, our model can be considered a more detailed, and biologically plausible, implementation of the biased competition model of attention. However, our model is more general as it can also explain a variety of other top-down processes in vision, such as figure/ground segmentation and contextual cueing. This model thus suggests that a common mechanism, involving cortical feedback pathways, is responsible for a range of phenomena and provides a unified account of currently disparate areas of research.

  7. Effects of acoustic feedback training in elite-standard Para-Rowing.

    Science.gov (United States)

    Schaffert, Nina; Mattes, Klaus

    2015-01-01

    Assessment and feedback devices have been regularly used in technique training in high-performance sports. Biomechanical analysis is mainly visually based and so can exclude athletes with visual impairments. The aim of this study was to examine the effects of auditory feedback on mean boat speed during on-water training of visually impaired athletes. The German National Para-Rowing team (six athletes, mean ± s, age 34.8 ± 10.6 years, body mass 76.5 ± 13.5 kg, stature 179.3 ± 8.6 cm) participated in the study. Kinematics included boat acceleration and distance travelled, collected with Sofirow at two intensities of training. The boat acceleration-time traces were converted online into acoustic feedback and presented via speakers during rowing (sections with and without alternately). Repeated-measures within-participant factorial ANOVA showed greater boat speed with acoustic feedback than baseline (0.08 ± 0.01 m·s(-1)). The time structure of rowing cycles was improved (extended time of positive acceleration). Questioning of athletes showed acoustic feedback to be a supportive training aid as it provided important functional information about the boat motion independent of vision. It gave access for visually impaired athletes to biomechanical analysis via auditory information. The concept for adaptive athletes has been successfully integrated into the preparation for the Para-Rowing World Championships and Paralympics.

  8. Artificial proprioceptive feedback for myoelectric control.

    Science.gov (United States)

    Pistohl, Tobias; Joshi, Deepak; Ganesh, Gowrishankar; Jackson, Andrew; Nazarpour, Kianoush

    2015-05-01

    The typical control of myoelectric interfaces, whether in laboratory settings or real-life prosthetic applications, largely relies on visual feedback because proprioceptive signals from the controlling muscles are either not available or very noisy. We conducted a set of experiments to test whether artificial proprioceptive feedback, delivered noninvasively to another limb, can improve control of a two-dimensional myoelectrically-controlled computer interface. In these experiments, participants were required to reach a target with a visual cursor that was controlled by electromyogram signals recorded from muscles of the left hand, while they were provided with an additional proprioceptive feedback on their right arm by moving it with a robotic manipulandum. Provision of additional artificial proprioceptive feedback improved the angular accuracy of their movements when compared to using visual feedback alone but did not increase the overall accuracy quantified with the average distance between the cursor and the target. The advantages conferred by proprioception were present only when the proprioceptive feedback had similar orientation to the visual feedback in the task space and not when it was mirrored, demonstrating the importance of congruency in feedback modalities for multi-sensory integration. Our results reveal the ability of the human motor system to learn new inter-limb sensory-motor associations; the motor system can utilize task-related sensory feedback, even when it is available on a limb distinct from the one being actuated. In addition, the proposed task structure provides a flexible test paradigm by which the effectiveness of various sensory feedback and multi-sensory integration for myoelectric prosthesis control can be evaluated.

  9. Diversity in School Performance Feedback Systems

    Science.gov (United States)

    Verhaeghe, Goedele; Schildkamp, Kim; Luyten, Hans; Valcke, Martin

    2015-01-01

    As data-based decision making is receiving increased attention in education, more and more school performance feedback systems (SPFSs) are being developed and used worldwide. These systems provide schools with data on their functioning. However, little research is available on the characteristics of the different SPFSs. Therefore, this study…

  10. Ring a bell? Adaptive Auditory Game Feedback to Sustain Performance in Stroke Rehabilitation

    DEFF Research Database (Denmark)

    Hald, Kasper; Knoche, Hendrik

    2016-01-01

    This paper investigates the effect of adaptive auditory feed- back on continued player performance for stroke patients in a Whack- a-Mole style tablet game. The feedback consisted of accumulatively in- creasing the pitch of positive feedback sounds on tasks with fast reaction time and resetting...... it after slow reaction times. The analysis was based on data was obtained in a field trial with lesion patients during their regular rehabilitation. The auditory feedback events were categorized by feedback type (positive/negative) and the associated pitch change of ei- ther high or low magnitude. Both...... feedback type and magnitude had a significant effect on players performance. Negative feedback improved re- action time on the subsequent hit by 0.42 second and positive feedback impaired performance by 0.15 seconds....

  11. Man-systems evaluation of moving base vehicle simulation motion cues. [human acceleration perception involving visual feedback

    Science.gov (United States)

    Kirkpatrick, M.; Brye, R. G.

    1974-01-01

    A motion cue investigation program is reported that deals with human factor aspects of high fidelity vehicle simulation. General data on non-visual motion thresholds and specific threshold values are established for use as washout parameters in vehicle simulation. A general purpose similator is used to test the contradictory cue hypothesis that acceleration sensitivity is reduced during a vehicle control task involving visual feedback. The simulator provides varying acceleration levels. The method of forced choice is based on the theory of signal detect ability.

  12. Adaptive learning in a compartmental model of visual cortex—how feedback enables stable category learning and refinement

    Science.gov (United States)

    Layher, Georg; Schrodt, Fabian; Butz, Martin V.; Neumann, Heiko

    2014-01-01

    The categorization of real world objects is often reflected in the similarity of their visual appearances. Such categories of objects do not necessarily form disjunct sets of objects, neither semantically nor visually. The relationship between categories can often be described in terms of a hierarchical structure. For instance, tigers and leopards build two separate mammalian categories, both of which are subcategories of the category Felidae. In the last decades, the unsupervised learning of categories of visual input stimuli has been addressed by numerous approaches in machine learning as well as in computational neuroscience. However, the question of what kind of mechanisms might be involved in the process of subcategory learning, or category refinement, remains a topic of active investigation. We propose a recurrent computational network architecture for the unsupervised learning of categorial and subcategorial visual input representations. During learning, the connection strengths of bottom-up weights from input to higher-level category representations are adapted according to the input activity distribution. In a similar manner, top-down weights learn to encode the characteristics of a specific stimulus category. Feedforward and feedback learning in combination realize an associative memory mechanism, enabling the selective top-down propagation of a category's feedback weight distribution. We suggest that the difference between the expected input encoded in the projective field of a category node and the current input pattern controls the amplification of feedforward-driven representations. Large enough differences trigger the recruitment of new representational resources and the establishment of additional (sub-) category representations. We demonstrate the temporal evolution of such learning and show how the proposed combination of an associative memory with a modulatory feedback integration successfully establishes category and subcategory representations

  13. Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

    Science.gov (United States)

    Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

    2013-01-01

    Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

  14. Impact of the Supervisor Feedback Environment on Creative Performance: A Moderated Mediation Model.

    Science.gov (United States)

    Zhang, Jian; Gong, Zhenxing; Zhang, Shuangyu; Zhao, Yujia

    2017-01-01

    Studies on the relationship between feedback and creative performance have only focused on the feedback-self and have underestimated the value of the feedback environment. Building on Self Determined Theory, the purpose of this article is to examine the relationship among feedback environment, creative personality, goal self-concordance and creative performance. Hierarchical regression analysis of a sample of 162 supervisor-employee dyads from nine industry firms. The results indicate that supervisor feedback environment is positively related to creative performance, the relationship between the supervisor feedback environment and creative performance is mediated by goal self-concordance perfectly and moderated by creative personality significantly. The mediation effort of goal self-concordance is significantly influenced by creative personality. The implication of improving employees' creative performance is further discussed. The present study advances several perspectives of previous studies, echoes recent suggestions that organizations interested in stimulating employee creativity might profitably focus on developing work contexts that support it.

  15. Stimulus-dependent modulation of visual neglect in a touch-screen cancellation task.

    Science.gov (United States)

    Keller, Ingo; Volkening, Katharina; Garbacenkaite, Ruta

    2015-05-01

    Patients with left-sided neglect frequently show omissions and repetitive behavior on cancellation tests. Using a touch-screen-based cancellation task, we tested how visual feedback and distracters influence the number of omissions and perseverations. Eighteen patients with left-sided visual neglect and 18 healthy controls performed four different cancellation tasks on an iPad touch screen: no feedback (the display did not change during the task), visual feedback (touched targets changed their color from black to green), visual feedback with distracters (20 distracters were evenly embedded in the display; detected targets changed their color from black to green), vanishing targets (touched targets disappeared from the screen). Except for the condition with vanishing targets, neglect patients had significantly more omissions and perseverations than healthy controls in the remaining three subtests. Both conditions providing feedback by changing the target color showed the highest number of omissions. Erasure of targets nearly diminished omissions completely. The highest rate of perseverations was observed in the no-feedback condition. The implementation of distracters led to a moderate number of perseverations. Visual feedback without distracters and vanishing targets abolished perseverations nearly completely. Visual feedback and the presence of distracters aggravated hemispatial neglect. This finding is compatible with impaired disengagement from the ipsilesional side as an important factor of visual neglect. Improvement of cancellation behavior with vanishing targets could have therapeutic implications. (c) 2015 APA, all rights reserved).

  16. Interwoven fluctuations during intermodal perception: fractality in head sway supports the use of visual feedback in haptic perceptual judgments by manual wielding.

    Science.gov (United States)

    Kelty-Stephen, Damian G; Dixon, James A

    2014-12-01

    Intermodal integration required for perceptual learning tasks is rife with individual differences. Participants vary in how they use perceptual information to one modality. One participant alone might change her own response over time. Participants vary further in their use of feedback through one modality to inform another modality. Two experiments test the general hypothesis that perceptual-motor fluctuations reveal both information use within modality and coordination among modalities. Experiment 1 focuses on perceptual learning in dynamic touch, in which participants use exploratory hand-wielding of unseen objects to make visually guided length judgments and use visual feedback to rescale their judgments of the same mechanical information. Previous research found that the degree of fractal temporal scaling (i.e., "fractality") in hand-wielding moderates the use of mechanical information. Experiment 1 shows that head-sway fractality moderates the use of visual information. Further, experience with feedback increases head-sway fractality and prolongs its effect on later hand-wielding fractality. Experiment 2 replicates effects of head-sway fractality moderating use of visual information in a purely visual-judgment task. Together, these findings suggest that fractal fluctuations may provide a modal-general window onto not just how participants use perceptual information but also how well they may integrate information among different modalities. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  17. Stereotype threat engenders neural attentional bias toward negative feedback to undermine performance.

    Science.gov (United States)

    Forbes, Chad E; Leitner, Jordan B

    2014-10-01

    Stereotype threat, a situational pressure individuals experience when they fear confirming a negative group stereotype, engenders a cascade of physiological stress responses, negative appraisals, and performance monitoring processes that tax working memory resources necessary for optimal performance. Less is known, however, about how stereotype threat biases attentional processing in response to performance feedback, and how such attentional biases may undermine performance. Women received feedback on math problems in stereotype threatening compared to stereotype-neutral contexts while continuous EEG activity was recorded. Findings revealed that stereotype threatened women elicited larger midline P100 ERPs, increased phase locking between anterior cingulate cortex and dorsolateral prefrontal cortex (two regions integral for attentional processes), and increased power in left fusiform gyrus in response to negative feedback compared to positive feedback and women in stereotype-neutral contexts. Increased power in left fusiform gyrus in response to negative feedback predicted underperformance on the math task among stereotype threatened women only. Women in stereotype-neutral contexts exhibited the opposite trend. Findings suggest that in stereotype threatening contexts, neural networks integral for attention and working memory are biased toward negative, stereotype confirming feedback at very early speeds of information processing. This bias, in turn, plays a role in undermining performance. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Perceptual learning improves visual performance in juvenile amblyopia.

    Science.gov (United States)

    Li, Roger W; Young, Karen G; Hoenig, Pia; Levi, Dennis M

    2005-09-01

    To determine whether practicing a position-discrimination task improves visual performance in children with amblyopia and to determine the mechanism(s) of improvement. Five children (age range, 7-10 years) with amblyopia practiced a positional acuity task in which they had to judge which of three pairs of lines was misaligned. Positional noise was produced by distributing the individual patches of each line segment according to a Gaussian probability function. Observers were trained at three noise levels (including 0), with each observer performing between 3000 and 4000 responses in 7 to 10 sessions. Trial-by-trial feedback was provided. Four of the five observers showed significant improvement in positional acuity. In those four observers, on average, positional acuity with no noise improved by approximately 32% and with high noise by approximately 26%. A position-averaging model was used to parse the improvement into an increase in efficiency or a decrease in equivalent input noise. Two observers showed increased efficiency (51% and 117% improvements) with no significant change in equivalent input noise across sessions. The other two observers showed both a decrease in equivalent input noise (18% and 29%) and an increase in efficiency (17% and 71%). All five observers showed substantial improvement in Snellen acuity (approximately 26%) after practice. Perceptual learning can improve visual performance in amblyopic children. The improvement can be parsed into two important factors: decreased equivalent input noise and increased efficiency. Perceptual learning techniques may add an effective new method to the armamentarium of amblyopia treatments.

  19. A memory advantage for past-oriented over future-oriented performance feedback.

    Science.gov (United States)

    Nash, Robert A; Winstone, Naomi E; Gregory, Samantha E A; Papps, Emily

    2018-03-05

    People frequently receive performance feedback that describes how well they achieved in the past, and how they could improve in future. In educational contexts, future-oriented (directive) feedback is often argued to be more valuable to learners than past-oriented (evaluative) feedback; critically, prior research led us to predict that it should also be better remembered. We tested this prediction in six experiments. Subjects read written feedback containing evaluative and directive comments, which supposedly related to essays they had previously written (Experiments 1-2), or to essays another person had written (Experiments 3-6). Subjects then tried to reproduce the feedback from memory after a short delay. In all six experiments, the data strongly revealed the opposite effect to the one we predicted: despite only small differences in wording, evaluative feedback was in fact recalled consistently better than directive feedback. Furthermore, even when adult subjects did recall directive feedback, they frequently misremembered it in an evaluative style. These findings appear at odds with the position that being oriented toward the future is advantageous to memory. They also raise important questions about the possible behavioral effects and generalizability of such biases, in terms of students' academic performance. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  20. Impact of the Supervisor Feedback Environment on Creative Performance: A Moderated Mediation Model

    OpenAIRE

    Zhang, Jian; Gong, Zhenxing; Zhang, Shuangyu; Zhao, Yujia

    2017-01-01

    Studies on the relationship between feedback and creative performance have only focused on the feedback-self and have underestimated the value of the feedback environment. Building on Self Determined Theory, the purpose of this article is to examine the relationship among feedback environment, creative personality, goal self-concordance and creative performance. Hierarchical regression analysis of a sample of 162 supervisor–employee dyads from nine industry firms. The results indicate that su...

  1. The effect of performance feedback on drivers' hazard perception ability and self-ratings.

    Science.gov (United States)

    Horswill, Mark S; Garth, Megan; Hill, Andrew; Watson, Marcus O

    2017-04-01

    Drivers' hazard perception ability has been found to predict crash risk, and novice drivers appear to be particularly poor at this skill. This competency appears to develop only slowly with experience, and this could partially be a result of poor quality performance feedback. We report an experiment in which we provided high-quality artificial feedback on individual drivers' performance in a validated video-based hazard perception test via either: (1) a graph-based comparison of hazard perception response times between the test-taker, the average driver, and an expert driver; (2) a video-based comparison between the same groups; or (3) both. All three types of feedback resulted in both an improvement in hazard perception performance and a reduction in self-rated hazard perception skill, compared with a no-feedback control group. Video-based and graph-based feedback combined resulted in a greater improvement in hazard perception performance than either of the individual components, which did not differ from one another. All three types of feedback eliminated participants' self-enhancement bias for hazard perception skill. Participants judged both interventions involving video feedback to be significantly more likely to improve their real-world driving than the no feedback control group. While all three forms of feedback had some value, the combined video and graph feedback intervention appeared to be the most effective across all outcome measures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Clinical performance feedback and quality improvement opportunities for perioperative physicians

    Directory of Open Access Journals (Sweden)

    Kaye AD

    2014-05-01

    Full Text Available Alan David Kaye,1 Olutoyin J Okanlawon,2 Richard D Urman21Department of Anesthesiology, Louisiana State University School of Medicine, New Orleans, LA, 2Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston MA, USAAbstract: Clinical performance feedback is an important component of the ongoing development and education of health care practitioners. For physicians, feedback about their clinical practice and outcomes is central to developing both confidence and competence at all stages of their medical careers. Cultural and financial infrastructures need to be in place, and the concept of feedback needs to be readily embraced and encouraged by clinical leadership and other stakeholders. The "buy-in" includes the expectation and view that feedback occurs on a routine basis, and those engaged in the process are both encouraged to participate and held accountable. Feedback must be part of an overarching quality improvement and physician education agenda; it is not meant to be an isolated, fragmented initiative that is typically undermined by lack of resources or systemic barriers to gaining improvement within programs. Effective feedback should be an integral part of clinical practice. Anesthesiologists and other perioperative physicians are identifying specialty-specific indicators that can be used when creating a broader quality improvement agenda. Placing a more immediate formal feedback strategy that focuses on goal-oriented behavior is rapidly becoming a mainstay. Physicians may use their individual feedback reports for reflection and designing personal development plans as lifelong learners and leaders in improving patient care.Keywords: physician education, outcomes measurement, performance improvement, anesthesiology

  3. Electrotactile feedback improves performance and facilitates learning in the routine grasping task

    Directory of Open Access Journals (Sweden)

    Milica Isaković

    2016-06-01

    Full Text Available Aim of this study was to investigate the feasibility of electrotactile feedback in closed loop training of force control during the routine grasping task. The feedback was provided using an array electrode and a simple six-level spatial coding, and the experiment was conducted in three amputee subjects. The psychometric tests confirmed that the subjects could perceive and interpret the electrotactile feedback with a high success rate. The subjects performed the routine grasping task comprising 4 blocks of 60 grasping trials. In each trial, the subjects employed feedforward control to close the hand and produce the desired grasping force (four levels. First (baseline and the last (validation session were performed in open loop, while the second and the third session (training included electrotactile feedback. The obtained results confirmed that using the feedback improved the accuracy and precision of the force control. In addition, the subjects performed significantly better in the validation vs. baseline session, therefore suggesting that electrotactile feedback can be used for learning and training of myoelectric control.

  4. Electrotactile Feedback Improves Performance and Facilitates Learning in the Routine Grasping Task.

    Science.gov (United States)

    Isaković, Milica; Belić, Minja; Štrbac, Matija; Popović, Igor; Došen, Strahinja; Farina, Dario; Keller, Thierry

    2016-06-13

    Aim of this study was to investigate the feasibility of electrotactile feedback in closed loop training of force control during the routine grasping task. The feedback was provided using an array electrode and a simple six-level spatial coding, and the experiment was conducted in three amputee subjects. The psychometric tests confirmed that the subjects could perceive and interpret the electrotactile feedback with a high success rate. The subjects performed the routine grasping task comprising 4 blocks of 60 grasping trials. In each trial, the subjects employed feedforward control to close the hand and produce the desired grasping force (four levels). First (baseline) and the last (validation) session were performed in open loop, while the second and the third session (training) included electrotactile feedback. The obtained results confirmed that using the feedback improved the accuracy and precision of the force control. In addition, the subjects performed significantly better in the validation vs. baseline session, therefore suggesting that electrotactile feedback can be used for learning and training of myoelectric control.

  5. The Use of Keywords for Delivering Immediate Performance Feedback on Teacher Competence Development

    Science.gov (United States)

    Coninx, Nele; Kreijns, Karel; Jochems, Wim

    2013-01-01

    Literature shows that feedback that is specific, immediate and goal-oriented is effective on (pre-service) teachers' performance. Synchronous coaching gives this kind of feedback. Due to immediateness of feedback, pre-service teachers can suffer from cognitive load. We propose a set of standardised keywords through which this performance feedback…

  6. Reliability of performance velocity for jump squats under feedback and nonfeedback conditions.

    Science.gov (United States)

    Randell, Aaron D; Cronin, John B; Keogh, Justin Wl; Gill, Nicholas D; Pedersen, Murray C

    2011-12-01

    Randell, AD, Cronin, JB, Keogh, JWL, Gill, ND, and Pedersen, MC. Reliability of performance velocity for jump squats under feedback and nonfeedback conditions. J Strength Cond Res 25(12): 3514-3518, 2011-Advancements in the monitoring of kinematic and kinetic variables during resistance training have resulted in the ability to continuously monitor performance and provide feedback during training. If equipment and software can provide reliable instantaneous feedback related to the variable of interest during training, it is thought that this may result in goal-oriented movement tasks that increase the likelihood of transference to on-field performance or at the very least improve the mechanical variable of interest. The purpose of this study was to determine the reliability of performance velocity for jump squats under feedback and nonfeedback conditions over 3 consecutive training sessions. Twenty subjects were randomly allocated to a feedback or nonfeedback group, and each group performed a total of 3 "jump squat" training sessions with the velocity of each repetition measured using a linear position transducer. There was less change in mean velocities between sessions 1-2 and sessions 2-3 (0.07 and 0.02 vs. 0.13 and -0.04 m·s), less random variation (TE = 0.06 and 0.06 vs. 0.10 and 0.07 m·s) and greater consistency (intraclass correlation coefficient = 0.83 and 0.87 vs. 0.53 and 0.74) between sessions for the feedback condition as compared to the nonfeedback condition. It was concluded that there is approximately a 50-50 probability that the provision of feedback was beneficial to the performance in the squat jump over multiple sessions. It is suggested that this has the potential for increasing transference to on-field performance or at the very least improving the mechanical variable of interest.

  7. Performance Analysis of Simple Channel Feedback Schemes for a Practical OFDMA System

    DEFF Research Database (Denmark)

    Pedersen, Klaus, I.; Kolding, Troels; Kovacs, Istvan

    2009-01-01

    In this paper, we evaluate the tradeoff between the amount of uplink channel feedback information and the orthogonal frequency-division multiple access (OFDMA) downlink performance with opportunistic frequency-domain packet scheduling. Three candidate channel feedback schemes are investigated......, including practical aspects, such as the effects of terminal measurement errors, bandwidth measurement granularity, quantization, and uplink signaling delays. The performance is evaluated by means of system-level simulations with detailed modeling of various radio resource-management algorithms, etc. Our...... results show that the optimal tradeoff between the channel feedback and the downlink OFDMA system performance depends on the radio channel frequency coherence bandwidth. We conclude that the so-called average best-M scheme is the most attractive channel feedback solution, where only the average channel...

  8. Peer video review and feedback improve performance in basic surgical skills.

    Science.gov (United States)

    Vaughn, Carolyn J; Kim, Edward; O'Sullivan, Patricia; Huang, Emily; Lin, Matthew Y C; Wyles, Susannah; Palmer, Barnard J A; Pierce, Jonathan L; Chern, Hueylan

    2016-02-01

    Incorporation of home-video assessments allows flexibility in feedback but requires faculty time. Peer feedback (PF) may provide additional benefits while avoiding these constraints. Twenty-four surgical interns completed a 12-week skills curriculum with home-video assignments focused on knot tying and suturing. Interns were randomized into 2 groups: PF or faculty feedback (FF). Peers and faculty provided feedback on home videos with checklists, global rating, and comments. Learners' skills were assessed at baseline, during, and at the conclusion of the curriculum. Performance of the 2 groups as rated by experts was compared. FF and PF were compared. Both groups improved from baseline, and the highest rated scores were seen on their home-video assessments. The PF group performed better at the final assessment than the FF group (effect size, .84). When using a checklist, there was no significant difference between scores given by peers and faculty. The PF group performed better at the final assessment, suggesting reviewing and analyzing another's performance may improve one's own performance. With checklists as guidance, peers can serve as raters comparable to faculty. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. A Computerized Tablet with Visual Feedback of Hand Position for Functional Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Mahta eKarimpoor

    2015-03-01

    Full Text Available Neuropsychological tests - behavioral tasks that very commonly involve handwriting and drawing - are widely used in the clinic to detect abnormal brain function. Functional magnetic resonance imaging (fMRI may be useful in increasing the specificity of such tests. However, performing complex pen-and-paper tests during fMRI involves engineering challenges. Previously, we developed an fMRI-compatible, computerized tablet system to address this issue. However, the tablet did not include visual feedback of hand position (VFHP, a human factors component that may be important for fMRI of certain patient populations. A real-time system was thus developed to provide VFHP and integrated with the tablet in an augmented reality display. The effectiveness of the system was initially tested in young healthy adults who performed various handwriting tasks in front of a computer display with and without VFHP. Pilot fMRI of writing tasks were performed by two representative individuals with and without VFHP. Quantitative analysis of the behavioral results indicated improved writing performance with VFHP. The pilot fMRI results suggest that writing with VFHP requires less neural resources compared to the without VFHP condition, to maintain similar behavior. Thus, the tablet system with VFHP is recommended for future fMRI studies involving patients with impaired brain function and where ecologically valid behavior is important.

  10. A computerized tablet with visual feedback of hand position for functional magnetic resonance imaging

    Science.gov (United States)

    Karimpoor, Mahta; Tam, Fred; Strother, Stephen C.; Fischer, Corinne E.; Schweizer, Tom A.; Graham, Simon J.

    2015-01-01

    Neuropsychological tests behavioral tasks that very commonly involve handwriting and drawing are widely used in the clinic to detect abnormal brain function. Functional magnetic resonance imaging (fMRI) may be useful in increasing the specificity of such tests. However, performing complex pen-and-paper tests during fMRI involves engineering challenges. Previously, we developed an fMRI-compatible, computerized tablet system to address this issue. However, the tablet did not include visual feedback of hand position (VFHP), a human factors component that may be important for fMRI of certain patient populations. A real-time system was thus developed to provide VFHP and integrated with the tablet in an augmented reality display. The effectiveness of the system was initially tested in young healthy adults who performed various handwriting tasks in front of a computer display with and without VFHP. Pilot fMRI of writing tasks were performed by two representative individuals with and without VFHP. Quantitative analysis of the behavioral results indicated improved writing performance with VFHP. The pilot fMRI results suggest that writing with VFHP requires less neural resources compared to the without VFHP condition, to maintain similar behavior. Thus, the tablet system with VFHP is recommended for future fMRI studies involving patients with impaired brain function and where ecologically valid behavior is important. PMID:25859201

  11. Visual target distance, but not visual cursor path length produces shifts in motor behavior

    Directory of Open Access Journals (Sweden)

    Nike eWendker

    2014-03-01

    Full Text Available When using tools effects in body space and distant space often do not correspond. Findings so far demonstrated that in this case visual feedback has more impact on action control than proprioceptive feedback. The present study varies the dimensional overlap between visual and proprioceptive action effects and investigates its impact on aftereffects in motor responses. In two experiments participants perform linear hand movements on a covered digitizer tablet to produce ∩-shaped cursor trajectories on the display. The shape of hand motion and cursor motion (linear vs. curved is dissimilar and therefore does not overlap. In one condition the length of hand amplitude and visual target distance is similar and constant while the length of the cursor path is dissimilar and varies. In another condition the length of the hand amplitude varies while the lengths of visual target distance (similar or dissimilar and cursor path (dissimilar are constant. First, we found that aftereffects depended on the relation between hand path length and visual target distance, and not on the relation between hand and cursor path length. Second, increasing contextual interference did not reveal larger aftereffects. Finally, data exploration demonstrated a considerable benefit from gain repetitions across trials when compared to gain switches. In conclusion, dimensional overlap between visual and proprioceptive action effects modulates human information processing in visually controlled actions. However, adjustment of the internal model seems to occur very fast for this kind of simple linear transformation, so that the impact of prior visual feedback is fleeting.

  12. Non-retinotopic motor-visual recalibration to temporal lag

    Directory of Open Access Journals (Sweden)

    Masaki eTsujita

    2012-11-01

    Full Text Available Temporal order judgment between the voluntary motor action and its perceptual feedback is important in distinguishing between a sensory feedback which is caused by observer’s own action and other stimulus, which are irrelevant to that action. Prolonged exposure to fixed temporal lag between motor action and visual feedback recalibrates motor-visual temporal relationship, and consequently shifts the point of subjective simultaneity (PSS. Previous studies on the audio-visual temporal recalibration without voluntary action revealed that both low and high level processing are involved. However, it is not clear how the low and high level processings affect the recalibration to constant temporal lag between voluntary action and visual feedback. This study examined retinotopic specificity of the motor-visual temporal recalibration. During the adaptation phase, observers repeatedly pressed a key, and visual stimulus was presented in left or right visual field with a fixed temporal lag (0 or 200 ms. In the test phase, observers performed a temporal order judgment for observer’s voluntary keypress and test stimulus, which was presented in the same as or opposite to the visual field in which the stimulus was presented in the adaptation phase. We found that the PSS was shifted toward the exposed lag in both visual fields. These results suggest that the low visual processing, which is retinotopically specific, has minor contribution to the multimodal adaptation, and that the adaptation to shift the PSS mainly depends upon the high level processing such as attention to specific properties of the stimulus.

  13. Using a Feedback Environment to Improve Creative Performance: A Dynamic Affect Perspective.

    Science.gov (United States)

    Gong, Zhenxing; Zhang, Na

    2017-01-01

    Prior research on feedback and creative performance has neglected the dynamic nature of affect and has focused only on the influence of positive affect. We argue that creative performance is the result of a dynamic process in which a person experiences a phase of negative affect and subsequently enters a state of high positive affect that is influenced by the feedback environment. Hierarchical regression was used to analyze a sample of 264 employees from seven industry firms. The results indicate that employees' perceptions of a supportive supervisor feedback environment indirectly influence their level of creative performance through positive affect (t2); the negative affect (t1) moderates the relationship between positive affect (t2) and creative performance (t2), rendering the relationship more positive if negative affect (t1) is high. The change in positive affect mediates the relationship between the supervisor feedback environment and creative performance; a decrease in negative affect moderates the relationship between increased positive affect and creative performance, rendering the relationship more positive if the decrease in negative affect is large. The implications for improving the creative performances of employees are further discussed.

  14. Using a Feedback Environment to Improve Creative Performance: A Dynamic Affect Perspective

    Directory of Open Access Journals (Sweden)

    Zhenxing Gong

    2017-08-01

    Full Text Available Prior research on feedback and creative performance has neglected the dynamic nature of affect and has focused only on the influence of positive affect. We argue that creative performance is the result of a dynamic process in which a person experiences a phase of negative affect and subsequently enters a state of high positive affect that is influenced by the feedback environment. Hierarchical regression was used to analyze a sample of 264 employees from seven industry firms. The results indicate that employees’ perceptions of a supportive supervisor feedback environment indirectly influence their level of creative performance through positive affect (t2; the negative affect (t1 moderates the relationship between positive affect (t2 and creative performance (t2, rendering the relationship more positive if negative affect (t1 is high. The change in positive affect mediates the relationship between the supervisor feedback environment and creative performance; a decrease in negative affect moderates the relationship between increased positive affect and creative performance, rendering the relationship more positive if the decrease in negative affect is large. The implications for improving the creative performances of employees are further discussed.

  15. Mastoidectomy simulation with combined visual and haptic feedback.

    Science.gov (United States)

    Agus, Marco; Giachetti, Andrea; Gobbetti, Enrico; Zanetti, Gianluigi; Zorcolo, Antonio; John, Nigel W; Stone, Robert J

    2002-01-01

    Mastoidectomy is one of the most common surgical procedures relating to the petrous bone. In this paper we describe our preliminary results in the realization of a virtual reality mastoidectomy simulator. Our system is designed to work on patient-specific volumetric object models directly derived from 3D CT and MRI images. The paper summarizes the detailed task analysis performed in order to define the system requirements, introduces the architecture of the prototype simulator, and discusses the initial feedback received from selected end users.

  16. Virtual reality in neurosurgical education: part-task ventriculostomy simulation with dynamic visual and haptic feedback.

    Science.gov (United States)

    Lemole, G Michael; Banerjee, P Pat; Luciano, Cristian; Neckrysh, Sergey; Charbel, Fady T

    2007-07-01

    Mastery of the neurosurgical skill set involves many hours of supervised intraoperative training. Convergence of political, economic, and social forces has limited neurosurgical resident operative exposure. There is need to develop realistic neurosurgical simulations that reproduce the operative experience, unrestricted by time and patient safety constraints. Computer-based, virtual reality platforms offer just such a possibility. The combination of virtual reality with dynamic, three-dimensional stereoscopic visualization, and haptic feedback technologies makes realistic procedural simulation possible. Most neurosurgical procedures can be conceptualized and segmented into critical task components, which can be simulated independently or in conjunction with other modules to recreate the experience of a complex neurosurgical procedure. We use the ImmersiveTouch (ImmersiveTouch, Inc., Chicago, IL) virtual reality platform, developed at the University of Illinois at Chicago, to simulate the task of ventriculostomy catheter placement as a proof-of-concept. Computed tomographic data are used to create a virtual anatomic volume. Haptic feedback offers simulated resistance and relaxation with passage of a virtual three-dimensional ventriculostomy catheter through the brain parenchyma into the ventricle. A dynamic three-dimensional graphical interface renders changing visual perspective as the user's head moves. The simulation platform was found to have realistic visual, tactile, and handling characteristics, as assessed by neurosurgical faculty, residents, and medical students. We have developed a realistic, haptics-based virtual reality simulator for neurosurgical education. Our first module recreates a critical component of the ventriculostomy placement task. This approach to task simulation can be assembled in a modular manner to reproduce entire neurosurgical procedures.

  17. Boosting the Motor Outcome of the Untrained Hand by Action Observation: Mirror Visual Feedback, Video Therapy, or Both Combined—What Is More Effective?

    Directory of Open Access Journals (Sweden)

    Florian Bähr

    2018-01-01

    Full Text Available Action observation (AO allows access to a network that processes visuomotor and sensorimotor inputs and is believed to be involved in observational learning of motor skills. We conducted three consecutive experiments to examine the boosting effect of AO on the motor outcome of the untrained hand by either mirror visual feedback (MVF, video therapy (VT, or a combination of both. In the first experiment, healthy participants trained either with MVF or without mirror feedback while in the second experiment, participants either trained with VT or observed animal videos. In the third experiment, participants first observed video clips that were followed by either training with MVF or training without mirror feedback. The outcomes for the untrained hand were quantified by scores from five motor tasks. The results demonstrated that MVF and VT significantly increase the motor performance of the untrained hand by the use of AO. We found that MVF was the most effective approach to increase the performance of the target effector. On the contrary, the combination of MVF and VT turns out to be less effective looking from clinical perspective. The gathered results suggest that action-related motor competence with the untrained hand is acquired by both mirror-based and video-based AO.

  18. Memory for performance feedback :a test of three self- motivation theories

    OpenAIRE

    Donlin, Joanne Mac

    1990-01-01

    The current study tests the adequacy of three self-motive theories to predict recall of performance feedback, memory sensitivity, and ratings of perceived accuracy. Self-enhancement (Jones, 1973) predicts individuals are motivated to maintain their self-esteem. Individuals will therefore recall positive relative to negative feedback and will rate positive feedback as more accurate. Self-consistency theory (Swann, 1985) predicts individuals are motivated to maintain their self-conceptions. The...

  19. The Effect of Delayed Visual Feedback on Synchrony Perception in a Tapping Task

    Directory of Open Access Journals (Sweden)

    Mirjam Keetels

    2011-10-01

    Full Text Available Sensory events following a motor action are, within limits, interpreted as a causal consequence of those actions. For example, the clapping of the hands is initiated by the motor system, but subsequently visual, auditory, and tactile information is provided and processed. In the present study we examine the effect of temporal disturbances in this chain of motor-sensory events. Participants are instructed to tap a surface with their finger in synchrony with a chain of 20 sound clicks (ISI 750 ms. We examined the effect of additional visual information on this ‘tap-sound’-synchronization task. During tapping, subjects will see a video of their own tapping hand on a screen in front of them. The video can either be in synchrony with the tap (real-time recording, or can be slightly delayed (∼40–160 ms. In a control condition, no video is provided. We explore whether ‘tap-sound’ synchrony will be shifted as a function of the delayed visual feedback. Results will provide fundamental insights into how the brain preserves a causal interpretation of motor actions and their sensory consequences.

  20. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam [Dept. of Radiation Oncology, Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Song, Jae Hoon [Dept. of Biomedical Engineering, Seoul St. Mary' s Hospital, Seoul (Korea, Republic of); Kim, Young Jae [Dept. of Radiological Technology, Gwang Yang Health Collage, Gwangyang (Korea, Republic of)

    2013-03-15

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam{sub t}ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule.

  1. Utility estimation of the application of auditory-visual-tactile sense feedback in respiratory gated radiation therapy

    International Nuclear Information System (INIS)

    Jo, Jung Hun; KIm, Byeong Jin; Roh, Shi Won; Lee, Hyeon Chan; Jang, Hyeong Jun; Kim, Hoi Nam; Song, Jae Hoon; Kim, Young Jae

    2013-01-01

    The purpose of this study was to evaluate the possibility to optimize the gated treatment delivery time and maintenance of stable respiratory by the introduction of breath with the assistance of auditory-visual-tactile sense. The experimenter's respiration were measured by ANZAI 4D system. We obtained natural breathing signal, monitor-induced breathing signal, monitor and ventilator-induced breathing signal, and breath-hold signal using real time monitor during 10 minutes beam-on-time. In order to check the stability of respiratory signals distributed in each group were compared with means, standard deviation, variation value, beam t ime of the respiratory signal. The stability of each respiratory was measured in consideration of deviation change studied in each respiratory time lapse. As a result of an analysis of respiratory signal, all experimenters has showed that breathing signal used both Real time monitor and Ventilator was the most stable and shortest time. In this study, it was evaluated that respiratory gated radiation therapy with auditory-visual-tactual sense and without auditory-visual-tactual sense feedback. The study showed that respiratory gated radiation therapy delivery time could significantly be improved by the application of video feedback when this is combined with audio-tactual sense assistance. This delivery technique did prove its feasibility to limit the tumor motion during treatment delivery for all patients to a defined value while maintaining the accuracy and proved the applicability of the technique in a conventional clinical schedule

  2. Perceptual learning increases the strength of the earliest signals in visual cortex.

    Science.gov (United States)

    Bao, Min; Yang, Lin; Rios, Cristina; He, Bin; Engel, Stephen A

    2010-11-10

    Training improves performance on most visual tasks. Such perceptual learning can modify how information is read out from, and represented in, later visual areas, but effects on early visual cortex are controversial. In particular, it remains unknown whether learning can reshape neural response properties in early visual areas independent from feedback arising in later cortical areas. Here, we tested whether learning can modify feedforward signals in early visual cortex as measured by the human electroencephalogram. Fourteen subjects were trained for >24 d to detect a diagonal grating pattern in one quadrant of the visual field. Training improved performance, reducing the contrast needed for reliable detection, and also reliably increased the amplitude of the earliest component of the visual evoked potential, the C1. Control orientations and locations showed smaller effects of training. Because the C1 arises rapidly and has a source in early visual cortex, our results suggest that learning can increase early visual area response through local receptive field changes without feedback from later areas.

  3. Understanding Surgical Resident and Fellow Perspectives on Their Operative Performance Feedback Needs: A Qualitative Study.

    Science.gov (United States)

    Bello, Ricardo J; Sarmiento, Samuel; Meyer, Meredith L; Rosson, Gedge D; Cooney, Damon S; Lifchez, Scott D; Cooney, Carisa M

    2018-04-20

    Operative performance feedback is essential for surgical training. We aimed to understand surgical trainees' views on their operative performance feedback needs and to characterize feedback to elucidate factors affecting its value from the resident perspective. Using a qualitative research approach, 2 research fellows conducted semistructured, one-on-one interviews with surgical trainees. We analyzed recurring themes generated during interviews related to feedback characteristics, as well as the extent to which performance rating tools can help meet trainees' operative feedback needs. Departments or divisions of general or plastic surgery at 9 US academic institutions. Surgical residents and clinical fellows in general or plastic surgery. We conducted 30 interviews with 9 junior residents, 14 senior residents, and 7 clinical fellows. Eighteen (60%) participants were in plastic and 12 (40%) were in general surgery. Twenty-four participants (80%) reported feedback as very or extremely important during surgical training. All trainees stated that verbal, face-to-face feedback is the most valuable, especially if occurring during (92%) or immediately after (65%) cases. Of those trainees using performance rating tools (74%), most (57%) expressed positive views about them but wanted the tools to complement and not replace verbal feedback in surgical education. Trainees value feedback more if received within 1 week or the case. Verbal, face-to-face feedback is very or extremely important to surgical trainees. Residents and fellows prefer to receive feedback during or immediately after a case and continue to value feedback if received within 1 week of the event. Performance rating tools can be useful for providing formative feedback and documentation but should not replace verbal, face-to-face feedback. Considering trainee views on feedback may help reduce perceived gaps in feedback demand-versus-supply in surgical training, which may be essential to overcoming current

  4. Looking at the ventriloquist: visual outcome of eye movements calibrates sound localization.

    Directory of Open Access Journals (Sweden)

    Daniel S Pages

    Full Text Available A general problem in learning is how the brain determines what lesson to learn (and what lessons not to learn. For example, sound localization is a behavior that is partially learned with the aid of vision. This process requires correctly matching a visual location to that of a sound. This is an intrinsically circular problem when sound location is itself uncertain and the visual scene is rife with possible visual matches. Here, we develop a simple paradigm using visual guidance of sound localization to gain insight into how the brain confronts this type of circularity. We tested two competing hypotheses. 1: The brain guides sound location learning based on the synchrony or simultaneity of auditory-visual stimuli, potentially involving a Hebbian associative mechanism. 2: The brain uses a 'guess and check' heuristic in which visual feedback that is obtained after an eye movement to a sound alters future performance, perhaps by recruiting the brain's reward-related circuitry. We assessed the effects of exposure to visual stimuli spatially mismatched from sounds on performance of an interleaved auditory-only saccade task. We found that when humans and monkeys were provided the visual stimulus asynchronously with the sound but as feedback to an auditory-guided saccade, they shifted their subsequent auditory-only performance toward the direction of the visual cue by 1.3-1.7 degrees, or 22-28% of the original 6 degree visual-auditory mismatch. In contrast when the visual stimulus was presented synchronously with the sound but extinguished too quickly to provide this feedback, there was little change in subsequent auditory-only performance. Our results suggest that the outcome of our own actions is vital to localizing sounds correctly. Contrary to previous expectations, visual calibration of auditory space does not appear to require visual-auditory associations based on synchrony/simultaneity.

  5. Expert monitoring and verbal feedback as sources of performance pressure.

    Science.gov (United States)

    Buchanan, John J; Park, Inchon; Chen, Jing; Mehta, Ranjana K; McCulloch, Austin; Rhee, Joohyun; Wright, David L

    2018-05-01

    The influence of monitoring-pressure and verbal feedback on the performance of the intrinsically stable bimanual coordination patterns of in-phase and anti-phase was examined. The two bimanual patterns were produced under three conditions: 1) no-monitoring, 2) monitoring-pressure (viewed by experts), and 3) monitoring-pressure (viewed by experts) combined with verbal feedback emphasizing poor performance. The bimanual patterns were produced at self-paced movement frequencies. Anti-phase coordination was always less stable than in-phase coordination across all three conditions. When performed under conditions 2 and 3, both bimanual patterns were performed with less variability in relative phase across a wide range of self-paced movement frequencies compared to the no-monitoring condition. Thus, monitoring-pressure resulted in performance stabilization rather than degradation and the presence of verbal feedback had no impact on the influence of monitoring pressure. The current findings are inconsistent with the predictions of explicit monitoring theory; however, the findings are consistent with studies that have revealed increased stability for the system's intrinsic dynamics as a result of attentional focus and intentional control. The results are discussed within the contexts of the dynamic pattern theory of coordination, explicit monitoring theory, and action-focused theories as explanations for choking under pressure. Copyright © 2018. Published by Elsevier B.V.

  6. A cognitive neuroprosthetic that uses cortical stimulation for somatosensory feedback

    Science.gov (United States)

    Klaes, Christian; Shi, Ying; Kellis, Spencer; Minxha, Juri; Revechkis, Boris; Andersen, Richard A.

    2014-10-01

    Objective. Present day cortical brain-machine interfaces (BMIs) have made impressive advances using decoded brain signals to control extracorporeal devices. Although BMIs are used in a closed-loop fashion, sensory feedback typically is visual only. However medical case studies have shown that the loss of somesthesis in a limb greatly reduces the agility of the limb even when visual feedback is available. Approach. To overcome this limitation, this study tested a closed-loop BMI that utilizes intracortical microstimulation to provide ‘tactile’ sensation to a non-human primate. Main result. Using stimulation electrodes in Brodmann area 1 of somatosensory cortex (BA1) and recording electrodes in the anterior intraparietal area, the parietal reach region and dorsal area 5 (area 5d), it was found that this form of feedback can be used in BMI tasks. Significance. Providing somatosensory feedback has the poyential to greatly improve the performance of cognitive neuroprostheses especially for fine control and object manipulation. Adding stimulation to a BMI system could therefore improve the quality of life for severely paralyzed patients.

  7. Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator: a randomized trial.

    Science.gov (United States)

    Strandbygaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde; Winkel, Per; Larsen, Christian Rifbjerg; Ringsted, Charlotte; Gluud, Christian; Grantcharov, Teodor; Ottesen, Bent; Sorensen, Jette Led

    2013-05-01

    To investigate the impact of instructor feedback versus no instructor feedback when training a complex operational task on a laparoscopic virtual reality simulator. : Simulators are now widely accepted as a training tool, but there is insufficient knowledge about how much feedback is necessary, which is useful for sustainable implementation. A randomized trial complying with CONSORT Statement. All participants had to reach a predefined proficiency level for a complex operational task on a virtual reality simulator. The intervention group received standardized instructor feedback a maximum of 3 times. The control group did not receive instructor feedback. Participants were senior medical students without prior laparoscopic experience (n = 99). Outcome measures were time, repetitions, and performance score to reach a predefined proficiency level. Furthermore, influence of sex and perception of own surgical skills were examined. Time (in minutes) and repetitions were reduced in the intervention group (162 vs 342 minutes; P less time (in minutes) than women (P = 0.037), but no sex difference was observed for repetitions (P = 0.20). Participants in the intervention group had higher self-perception regarding surgical skills after the trial (P = 0.011). Instructor feedback increases the efficiency when training a complex operational task on a virtual reality simulator; time and repetitions used to achieve a predefined proficiency level were significantly reduced in the group that received instructor feedback compared with the control group. NCT01497782.

  8. CPR performance in the presence of audiovisual feedback or football shoulder pads.

    Science.gov (United States)

    Tanaka, Shota; Rodrigues, Wayne; Sotir, Susan; Sagisaka, Ryo; Tanaka, Hideharu

    2017-01-01

    The initiation of cardiopulmonary resuscitation (CPR) can be complicated by the use of protective equipment in contact sports, and the rate of success in resuscitating the patient depends on the time from incident to start of CPR. The aim of our study was to see if (1) previous training, (2) the presence of audiovisual feedback and (3) the presence of football shoulder pads (FSP) affected the quality of chest compressions. Six basic life support certified athletic training students (BLS-ATS), six basic life support certified emergency medical service personnel (BLS-EMS) and six advanced cardiac life support certified emergency medical service personnel (ACLS-EMS) participated in a crossover manikin study. A quasi-experimental repeated measures design was used to measure the chest compression depth (cm), rate (cpm), depth accuracy (%) and rate accuracy (%) on four different conditions by using feedback and/or FSP. Real CPR Help manufactured by ZOLL (Chelmsford, Massachusetts, USA) was used for the audiovisual feedback. Three participants from each group performed 2 min of chest compressions at baseline first, followed by compressions with FSP, with feedback and with both FSP and feedback (FSP+feedback). The other three participants from each group performed compressions at baseline first, followed by compressions with FSP+feedback, feedback and FSP. CPR performance did not differ between the groups at baseline (median (IQR), BLS-ATS: 5.0 (4.4-6.1) cm, 114(96-131) cpm; BLS-EMS: 5.4 (4.1-6.4) cm, 112(99-131) cpm; ACLS-EMS: 6.4 (5.7-6.7) cm, 138(113-140) cpm; depth p=0.10, rate p=0.37). A statistically significant difference in the percentage of depth accuracy was found with feedback (median (IQR), 13.8 (0.9-49.2)% vs 69.6 (32.3-85.8)%; p=0.0002). The rate accuracy was changed from 17.1 (0-80.7)% without feedback to 59.2 (17.3-74.3)% with feedback (p=0.50). The use of feedback was effective for depth accuracy, especially in the BLS-ATS group, regardless of the

  9. The effect of visual-motion time-delays on pilot performance in a simulated pursuit tracking task

    Science.gov (United States)

    Miller, G. K., Jr.; Riley, D. R.

    1977-01-01

    An experimental study was made to determine the effect on pilot performance of time delays in the visual and motion feedback loops of a simulated pursuit tracking task. Three major interrelated factors were identified: task difficulty either in the form of airplane handling qualities or target frequency, the amount and type of motion cues, and time delay itself. In general, the greater the task difficulty, the smaller the time delay that could exist without degrading pilot performance. Conversely, the greater the motion fidelity, the greater the time delay that could be tolerated. The effect of motion was, however, pilot dependent.

  10. Virtual Hand Feedback Reduces Reaction Time in an Interactive Finger Reaching Task.

    Directory of Open Access Journals (Sweden)

    Johannes Brand

    Full Text Available Computer interaction via visually guided hand or finger movements is a ubiquitous part of daily computer usage in work or gaming. Surprisingly, however, little is known about the performance effects of using virtual limb representations versus simpler cursors. In this study 26 healthy right-handed adults performed cued index finger flexion-extension movements towards an on-screen target while wearing a data glove. They received each of four different types of real-time visual feedback: a simple circular cursor, a point light pattern indicating finger joint positions, a cartoon hand and a fully shaded virtual hand. We found that participants initiated the movements faster when receiving feedback in the form of a hand than when receiving circular cursor or point light feedback. This overall difference was robust for three out of four hand versus circle pairwise comparisons. The faster movement initiation for hand feedback was accompanied by a larger movement amplitude and a larger movement error. We suggest that the observed effect may be related to priming of hand information during action perception and execution affecting motor planning and execution. The results may have applications in the use of body representations in virtual reality applications.

  11. Learning of Temporal and Spatial Movement Aspects: A Comparison of Four Types of Haptic Control and Concurrent Visual Feedback.

    Science.gov (United States)

    Rauter, Georg; Sigrist, Roland; Riener, Robert; Wolf, Peter

    2015-01-01

    In literature, the effectiveness of haptics for motor learning is controversially discussed. Haptics is believed to be effective for motor learning in general; however, different types of haptic control enhance different movement aspects. Thus, in dependence on the movement aspects of interest, one type of haptic control may be effective whereas another one is not. Therefore, in the current work, it was investigated if and how different types of haptic controllers affect learning of spatial and temporal movement aspects. In particular, haptic controllers that enforce active participation of the participants were expected to improve spatial aspects. Only haptic controllers that provide feedback about the task's velocity profile were expected to improve temporal aspects. In a study on learning a complex trunk-arm rowing task, the effect of training with four different types of haptic control was investigated: position control, path control, adaptive path control, and reactive path control. A fifth group (control) trained with visual concurrent augmented feedback. As hypothesized, the position controller was most effective for learning of temporal movement aspects, while the path controller was most effective in teaching spatial movement aspects of the rowing task. Visual feedback was also effective for learning temporal and spatial movement aspects.

  12. Self-Controlled Feedback for a Complex Motor Task

    Directory of Open Access Journals (Sweden)

    Wolf Peter

    2011-12-01

    Full Text Available Self-controlled augmented feedback enhances learning of simple motor tasks. Thereby, learners tend to request feedback after trials that were rated as good by themselves. Feedback after good trials promotes positive reinforcement, which enhances motor learning. The goal of this study was to investigate when naïve learners request terminal visual feedback in a complex motor task, as conclusions drawn on simple tasks can hardly be transferred to complex tasks. Indeed, seven of nine learners stated to have intended to request feedback predominantly after good trials, but in contrast to their intention, kinematic analysis showed that feedback was rather requested randomly (23% after good, 44% after intermediate, 33% after bad trials. Moreover, requesting feedback after good trials did not correlate with learning success. It seems that self-estimation of performance in complex tasks is challenging. As a consequence, learners might have focused on certain movement aspects rather than on the overall movement. Further studies should assess the current focus of the learner in detail to gain more insight in self-estimation capabilities during complex motor task learning.

  13. Relating Standardized Visual Perception Measures to Simulator Visual System Performance

    Science.gov (United States)

    Kaiser, Mary K.; Sweet, Barbara T.

    2013-01-01

    Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

  14. Psycho-physiological assessment of a prosthetic hand sensory feedback system based on an auditory display: a preliminary study.

    Science.gov (United States)

    Gonzalez, Jose; Soma, Hirokazu; Sekine, Masashi; Yu, Wenwei

    2012-06-09

    Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues) have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user's mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. 10 male subjects (26+/-years old), participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF), Visual Feedback only control (VF), and Audiovisual Feedback control (AVF). For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject's EEG, ECG, electro-dermal activity (EDA), and respiration rate were measured. The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback). Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. The performance improvements when using auditory cues, along with vision

  15. Psycho-physiological assessment of a prosthetic hand sensory feedback system based on an auditory display: a preliminary study

    Directory of Open Access Journals (Sweden)

    Gonzalez Jose

    2012-06-01

    Full Text Available Abstract Background Prosthetic hand users have to rely extensively on visual feedback, which seems to lead to a high conscious burden for the users, in order to manipulate their prosthetic devices. Indirect methods (electro-cutaneous, vibrotactile, auditory cues have been used to convey information from the artificial limb to the amputee, but the usability and advantages of these feedback methods were explored mainly by looking at the performance results, not taking into account measurements of the user’s mental effort, attention, and emotions. The main objective of this study was to explore the feasibility of using psycho-physiological measurements to assess cognitive effort when manipulating a robot hand with and without the usage of a sensory substitution system based on auditory feedback, and how these psycho-physiological recordings relate to temporal and grasping performance in a static setting. Methods 10 male subjects (26+/-years old, participated in this study and were asked to come for 2 consecutive days. On the first day the experiment objective, tasks, and experiment setting was explained. Then, they completed a 30 minutes guided training. On the second day each subject was tested in 3 different modalities: Auditory Feedback only control (AF, Visual Feedback only control (VF, and Audiovisual Feedback control (AVF. For each modality they were asked to perform 10 trials. At the end of each test, the subject had to answer the NASA TLX questionnaire. Also, during the test the subject’s EEG, ECG, electro-dermal activity (EDA, and respiration rate were measured. Results The results show that a higher mental effort is needed when the subjects rely only on their vision, and that this effort seems to be reduced when auditory feedback is added to the human-machine interaction (multimodal feedback. Furthermore, better temporal performance and better grasping performance was obtained in the audiovisual modality. Conclusions The performance

  16. Towards real-time feedback in high performance speed skating

    NARCIS (Netherlands)

    van der Eb, Jeroen; Zandee, Willem; van den Bogaard, Timo; Geraets, Sjoerd; Veeger, H.E.J.; Beek, Peter; Potthast, Wolfgang; Niehoff, Anja; David, Sina

    2017-01-01

    The aim of the current study is to evaluate several performance indicators to be used as real-time feedback in the coming experiments to enhance performance of elite speeds skaters. Six speed skaters, wearing one IMU per skate, collected data over one full training season to evaluate and pinpoint

  17. Real-time modulation of visual feedback on human full-body movements in a virtual mirror: development and proof-of-concept

    NARCIS (Netherlands)

    Roosink, M.; Robitaille, N.; McFadyen, B.J.; Hebert, L.J.; Jackson, P.L.; Bouyer, L.J.; Mercier, C.

    2015-01-01

    BACKGROUND: Virtual reality (VR) provides interactive multimodal sensory stimuli and biofeedback, and can be a powerful tool for physical and cognitive rehabilitation. However, existing systems have generally not implemented realistic full-body avatars and/or a scaling of visual movement feedback.

  18. Treatment Integrity Enhancement via Performance Feedback Conceptualized as an Exercise in Social Influence

    Science.gov (United States)

    Erchul, William P.

    2013-01-01

    This commentary is in response to the article "Effects of Verbal and Written Performance Feedback on Treatment Adherence" (Kaufman, Codding, Markus, Tryon, & Kyse, this issue). The overall recommendation to those who study treatment integrity using performance feedback methods is to incorporate theories and research on social…

  19. Evaluating the Evidence Base of Performance Feedback in Preservice Special Education Teacher Training

    Science.gov (United States)

    Cornelius, Kyena E.; Nagro, Sarah A.

    2014-01-01

    Performance feedback is commonly used during field experiences to improve desired teaching behaviors in preservice teachers. The authors identify eight single-subject studies examining the effects of performance feedback in preservice teachers to determine the evidence base for this practice. These eight studies are reviewed using quality…

  20. Augmenting performance feedback does not affect 4 km cycling time-trials in the heat.

    Science.gov (United States)

    Waldron, Mark; Villerius, Vincent; Murphy, Aron

    2015-01-01

    We compared the effects of (1) accurate and (2) surreptitiously augmented performance feedback on power output and physiological responses to a 4000 m time-trial in the heat. Nine cyclists completed a baseline (BaseL) 4000 m time-trial in ambient temperatures of 30°C, followed by two further 4000 m time-trials at the same temperature, randomly assigning the participants to an accurate (ACC; accurate feedback of baseline) or deceived (DEC; 2% increase above baseline) feedback group. The total power output (PO) and aerobic (Paer) and anaerobic (Pan) contributions were determined at 0.4 km stages during the time-trials, alongside measurements of rectal (Trec) and skin (Tskin) temperatures. There were no differences (P > 0.05) in any of the variables between BaseL, ACC and DEC, despite increases (P 0.05) between feedback condition and time-trial stage. Providing surreptitiously augmented performance feedback to well-trained cyclists did not alter their performance or physiological responses to a 4000 m time-trial in a hot environment. The assumed influence of augmented performance feedback was nullified in the heat, perhaps reflecting a central down-regulation of exercise intensity in response to an increased body temperature.

  1. Feedback and Incentives

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie Claire

    2009-01-01

    This paper experimentally investigates the impact of different pay schemes and relative performance feedback policies on employee effort. We explore three feedback rules: no feedback on relative performance, feedback given halfway through the production period, and continuously updated feedback. ...... behind, and front runners do not slack off. But in both pay schemes relative performance feedback reduces the quality of the low performers' work; we refer to this as a "negative quality peer effect"....

  2. Analysis of Feedback in after Action Reviews

    Science.gov (United States)

    1987-06-01

    CONNTSM Page INTRODUCTIUN . . . . . . . . . . . . . . . . . . . A Perspective on Feedback. . ....... • • ..... • 1 Overviev of %,•urrent Research...part of their training program . The AAR is in marked contrast to the critique method of feedback which is often used in military training. The AAR...feedback is task-inherent feedback. Task-inherent feedback refers to human-machine interacting systems, e.g., computers , where in a visual tracking task

  3. Performance feedback: An exploratory study to examine the acceptability and impact for interdisciplinary primary care teams

    Science.gov (United States)

    2011-01-01

    Background This mixed methods study was designed to explore the acceptability and impact of feedback of team performance data to primary care interdisciplinary teams. Methods Seven interdisciplinary teams were offered a one-hour, facilitated performance feedback session presenting data from a comprehensive, previously-conducted evaluation, selecting highlights such as performance on chronic disease management, access, patient satisfaction and team function. Results Several recurrent themes emerged from participants' surveys and two rounds of interviews within three months of the feedback session. Team performance measurement and feedback was welcomed across teams and disciplines. This feedback could build the team, the culture, and the capacity for quality improvement. However, existing performance indicators do not equally reflect the role of different disciplines within an interdisciplinary team. Finally, the effect of team performance feedback on intentions to improve performance was hindered by a poor understanding of how the team could use the data. Conclusions The findings further our understanding of how performance feedback may engage interdisciplinary team members in improving the quality of primary care and the unique challenges specific to these settings. There is a need to develop a shared sense of responsibility and agenda for quality improvement. Therefore, more efforts to develop flexible and interactive performance-reporting structures (that better reflect contributions from all team members) in which teams could specify the information and audience may assist in promoting quality improvement. PMID:21443806

  4. The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account.

    Science.gov (United States)

    Cohen Hoffing, Russell; Karvelis, Povilas; Rupprechter, Samuel; Seriès, Peggy; Seitz, Aaron R

    2018-01-01

    Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM) to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB) to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB), rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch). While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT) switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.

  5. Flemish Primary Teachers' Use of School Performance Feedback and the Relationship with School Characteristics

    Science.gov (United States)

    Vanhoof, Jan; Verhaeghe, Goedele; Van Petegem, Peter; Valcke, Martin

    2012-01-01

    Background: Schools are increasingly confronted with the challenges that information about school performance brings with it. It is common for schools' use of performance feedback to be limited. Equally, however, there are documented cases in which school performance feedback is meaningfully used. Purpose: This study looks at how Flemish primary…

  6. Does Top-Down Feedback Modulate the Encoding of Orthographic Representations During Visual-Word Recognition?

    Science.gov (United States)

    Perea, Manuel; Marcet, Ana; Vergara-Martínez, Marta

    2016-09-01

    In masked priming lexical decision experiments, there is a matched-case identity advantage for nonwords, but not for words (e.g., ERTAR-ERTAR words when top-down feedback is minimized. We employed a task that taps prelexical orthographic processes: the masked prime same-different task. For "same" trials, results showed faster response times for targets when preceded by a briefly presented matched-case identity prime than when preceded by a mismatched-case identity prime. Importantly, this advantage was similar in magnitude for nonwords and words. This finding constrains the interplay of bottom-up versus top-down mechanisms in models of visual-word identification.

  7. Adaptive learning in a compartmental model of visual cortex - how feedback enables stable category learning and refinement

    Directory of Open Access Journals (Sweden)

    Georg eLayher

    2014-12-01

    Full Text Available The categorization of real world objects is often reflected in the similarity of their visual appearances. Such categories of objects do not necessarily form disjunct sets of objects, neither semantically nor visually. The relationship between categories can often be described in terms of a hierarchical structure. For instance, tigers and leopards build two separate mammalian categories, but both belong to the category of felines. In other words, tigers and leopards are subcategories of the category Felidae. In the last decades, the unsupervised learning of categories of visual input stimuli has been addressed by numerous approaches in machine learning as well as in the computational neurosciences. However, the question of what kind of mechanisms might be involved in the process of subcategory learning, or category refinement, remains a topic of active investigation. We propose a recurrent computational network architecture for the unsupervised learning of categorial and subcategorial visual input representations. During learning, the connection strengths of bottom-up weights from input to higher-level category representations are adapted according to the input activity distribution. In a similar manner, top-down weights learn to encode the characteristics of a specific stimulus category. Feedforward and feedback learning in combination realize an associative memory mechanism, enabling the selective top-down propagation of a category's feedback weight distribution. We suggest that the difference between the expected input encoded in the projective field of a category node and the current input pattern controls the amplification of feedforward-driven representations. Large enough differences trigger the recruitment of new representational resources and the establishment of (sub- category representations. We demonstrate the temporal evolution of such learning and show how the approach successully establishes category and subcategory

  8. Can executive control be influenced by performance feedback? Two experimental studies with younger and older adults

    Directory of Open Access Journals (Sweden)

    Barbara eDrueke

    2012-04-01

    Full Text Available Executive control describes a wide range of cognitive processes which are critical for the goal-directed regulation of stimulus processing and action regulation. Previous studies have shown that executive control performance declines with age but yet, it is still not clear whether different internal and external factors - as performance feedback and age - influence these cognitive processes and how they might interact with each other. Therefore, we investigated feedback effects in the flanker task in young as well as in older adults in two experiments. Performance feedback significantly improved executive performance in younger adults at the expense of errors. In older adults, feedback also led to higher error rates, but had no significant effect on executive performance which might be due to stronger interference. Results indicate that executive functions can be positively influenced by performance feedback in younger adults, but not necessarily in older adults.

  9. A Systematic Review of the Literature on Parenting of Young Children with Visual Impairments and the Adaptions for Video-Feedback Intervention to Promote Positive Parenting (VIPP)

    NARCIS (Netherlands)

    van den Broek, Ellen G. C.; van Eijden, Ans J P M; Overbeek, Mathilde M.; Kef, Sabina; Sterkenburg, Paula S.; Schuengel, Carlo

    Secure parent-child attachment may help children to overcome the challenges of growing up with a visual or visual-and-intellectual impairment. A large literature exists that provides a blueprint for interventions that promote parental sensitivity and secure attachment. The Video-feedback

  10. Barriers to using eHealth data for clinical performance feedback in Malawi: A case study.

    Science.gov (United States)

    Landis-Lewis, Zach; Manjomo, Ronald; Gadabu, Oliver J; Kam, Matthew; Simwaka, Bertha N; Zickmund, Susan L; Chimbwandira, Frank; Douglas, Gerald P; Jacobson, Rebecca S

    2015-10-01

    Sub-optimal performance of healthcare providers in low-income countries is a critical and persistent global problem. The use of electronic health information technology (eHealth) in these settings is creating large-scale opportunities to automate performance measurement and provision of feedback to individual healthcare providers, to support clinical learning and behavior change. An electronic medical record system (EMR) deployed in 66 antiretroviral therapy clinics in Malawi collects data that supervisors use to provide quarterly, clinic-level performance feedback. Understanding barriers to provision of eHealth-based performance feedback for individual healthcare providers in this setting could present a relatively low-cost opportunity to significantly improve the quality of care. The aims of this study were to identify and describe barriers to using EMR data for individualized audit and feedback for healthcare providers in Malawi and to consider how to design technology to overcome these barriers. We conducted a qualitative study using interviews, observations, and informant feedback in eight public hospitals in Malawi where an EMR system is used. We interviewed 32 healthcare providers and conducted seven hours of observation of system use. We identified four key barriers to the use of EMR data for clinical performance feedback: provider rotations, disruptions to care processes, user acceptance of eHealth, and performance indicator lifespan. Each of these factors varied across sites and affected the quality of EMR data that could be used for the purpose of generating performance feedback for individual healthcare providers. Using routinely collected eHealth data to generate individualized performance feedback shows potential at large-scale for improving clinical performance in low-resource settings. However, technology used for this purpose must accommodate ongoing changes in barriers to eHealth data use. Understanding the clinical setting as a complex adaptive

  11. Muscle involvement during intermittent contraction patterns with different target force feedback modes

    DEFF Research Database (Denmark)

    Sjøgaard, G; Jørgensen, L V; Ekner, D

    2000-01-01

    and following 30 min of intermittent contractions showed larger fatigue development with proprioceptive feedback than visual feedback. Also rating of perceived exertion increased more during proprioceptive feedback than visual feedback. This may in part be explained by small differences in the mechanics during......: Feedback mode significantly effects the muscle involvement and fatigue during intermittent contractions. RelevanceIntermittent contractions are common in many work places and various feedback modes are being given regarding work requirements. The choice of feedback may significantly affect the muscle load...... and consequently the development muscle fatigue and disorders....

  12. Network interactions underlying mirror feedback in stroke: A dynamic causal modeling study

    Directory of Open Access Journals (Sweden)

    Soha Saleh

    2017-01-01

    Full Text Available Mirror visual feedback (MVF is potentially a powerful tool to facilitate recovery of disordered movement and stimulate activation of under-active brain areas due to stroke. The neural mechanisms underlying MVF have therefore been a focus of recent inquiry. Although it is known that sensorimotor areas can be activated via mirror feedback, the network interactions driving this effect remain unknown. The aim of the current study was to fill this gap by using dynamic causal modeling to test the interactions between regions in the frontal and parietal lobes that may be important for modulating the activation of the ipsilesional motor cortex during mirror visual feedback of unaffected hand movement in stroke patients. Our intent was to distinguish between two theoretical neural mechanisms that might mediate ipsilateral activation in response to mirror-feedback: transfer of information between bilateral motor cortices versus recruitment of regions comprising an action observation network which in turn modulate the motor cortex. In an event-related fMRI design, fourteen chronic stroke subjects performed goal-directed finger flexion movements with their unaffected hand while observing real-time visual feedback of the corresponding (veridical or opposite (mirror hand in virtual reality. Among 30 plausible network models that were tested, the winning model revealed significant mirror feedback-based modulation of the ipsilesional motor cortex arising from the contralesional parietal cortex, in a region along the rostral extent of the intraparietal sulcus. No winning model was identified for the veridical feedback condition. We discuss our findings in the context of supporting the latter hypothesis, that mirror feedback-based activation of motor cortex may be attributed to engagement of a contralateral (contralesional action observation network. These findings may have important implications for identifying putative cortical areas, which may be targeted with

  13. The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account

    Directory of Open Access Journals (Sweden)

    Russell Cohen Hoffing

    2018-02-01

    Full Text Available Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB, rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch. While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.

  14. Keeping Pace with Your Eating: Visual Feedback Affects Eating Rate in Humans.

    Directory of Open Access Journals (Sweden)

    Laura L Wilkinson

    Full Text Available Deliberately eating at a slower pace promotes satiation and eating quickly has been associated with a higher body mass index. Therefore, understanding factors that affect eating rate should be given high priority. Eating rate is affected by the physical/textural properties of a food, by motivational state, and by portion size and palatability. This study explored the prospect that eating rate is also influenced by a hitherto unexplored cognitive process that uses ongoing perceptual estimates of the volume of food remaining in a container to adjust intake during a meal. A 2 (amount seen; 300 ml or 500 ml x 2 (amount eaten; 300 ml or 500 ml between-subjects design was employed (10 participants in each condition. In two 'congruent' conditions, the same amount was seen at the outset and then subsequently consumed (300 ml or 500 ml. To dissociate visual feedback of portion size and actual amount consumed, food was covertly added or removed from a bowl using a peristaltic pump. This created two additional 'incongruent' conditions, in which 300 ml was seen but 500 ml was eaten or vice versa. We repeated these conditions using a savoury soup and a sweet dessert. Eating rate (ml per second was assessed during lunch. After lunch we assessed fullness over a 60-minute period. In the congruent conditions, eating rate was unaffected by the actual volume of food that was consumed (300 ml or 500 ml. By contrast, we observed a marked difference across the incongruent conditions. Specifically, participants who saw 300 ml but actually consumed 500 ml ate at a faster rate than participants who saw 500 ml but actually consumed 300 ml. Participants were unaware that their portion size had been manipulated. Nevertheless, when it disappeared faster or slower than anticipated they adjusted their rate of eating accordingly. This suggests that the control of eating rate involves visual feedback and is not a simple reflexive response to orosensory stimulation.

  15. Keeping Pace with Your Eating: Visual Feedback Affects Eating Rate in Humans.

    Science.gov (United States)

    Wilkinson, Laura L; Ferriday, Danielle; Bosworth, Matthew L; Godinot, Nicolas; Martin, Nathalie; Rogers, Peter J; Brunstrom, Jeffrey M

    2016-01-01

    Deliberately eating at a slower pace promotes satiation and eating quickly has been associated with a higher body mass index. Therefore, understanding factors that affect eating rate should be given high priority. Eating rate is affected by the physical/textural properties of a food, by motivational state, and by portion size and palatability. This study explored the prospect that eating rate is also influenced by a hitherto unexplored cognitive process that uses ongoing perceptual estimates of the volume of food remaining in a container to adjust intake during a meal. A 2 (amount seen; 300 ml or 500 ml) x 2 (amount eaten; 300 ml or 500 ml) between-subjects design was employed (10 participants in each condition). In two 'congruent' conditions, the same amount was seen at the outset and then subsequently consumed (300 ml or 500 ml). To dissociate visual feedback of portion size and actual amount consumed, food was covertly added or removed from a bowl using a peristaltic pump. This created two additional 'incongruent' conditions, in which 300 ml was seen but 500 ml was eaten or vice versa. We repeated these conditions using a savoury soup and a sweet dessert. Eating rate (ml per second) was assessed during lunch. After lunch we assessed fullness over a 60-minute period. In the congruent conditions, eating rate was unaffected by the actual volume of food that was consumed (300 ml or 500 ml). By contrast, we observed a marked difference across the incongruent conditions. Specifically, participants who saw 300 ml but actually consumed 500 ml ate at a faster rate than participants who saw 500 ml but actually consumed 300 ml. Participants were unaware that their portion size had been manipulated. Nevertheless, when it disappeared faster or slower than anticipated they adjusted their rate of eating accordingly. This suggests that the control of eating rate involves visual feedback and is not a simple reflexive response to orosensory stimulation.

  16. Feedback associated with expectation for larger-reward improves visuospatial working memory performances in children with ADHD.

    Science.gov (United States)

    Hammer, Rubi; Tennekoon, Michael; Cooke, Gillian E; Gayda, Jessica; Stein, Mark A; Booth, James R

    2015-08-01

    We tested the interactive effect of feedback and reward on visuospatial working memory in children with ADHD. Seventeen boys with ADHD and 17 Normal Control (NC) boys underwent functional magnetic resonance imaging (fMRI) while performing four visuospatial 2-back tasks that required monitoring the spatial location of letters presented on a display. Tasks varied in reward size (large; small) and feedback availability (no-feedback; feedback). While the performance of NC boys was high in all conditions, boys with ADHD exhibited higher performance (similar to those of NC boys) only when they received feedback associated with large-reward. Performance pattern in both groups was mirrored by neural activity in an executive function neural network comprised of few distinct frontal brain regions. Specifically, neural activity in the left and right middle frontal gyri of boys with ADHD became normal-like only when feedback was available, mainly when feedback was associated with large-reward. When feedback was associated with small-reward, or when large-reward was expected but feedback was not available, boys with ADHD exhibited altered neural activity in the medial orbitofrontal cortex and anterior insula. This suggests that contextual support normalizes activity in executive brain regions in children with ADHD, which results in improved working memory. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Enhanced visual performance in obsessive compulsive personality disorder.

    Science.gov (United States)

    Ansari, Zohreh; Fadardi, Javad Salehi

    2016-12-01

    Visual performance is considered as commanding modality in human perception. We tested whether Obsessive-compulsive personality disorder (OCPD) people do differently in visual performance tasks than people without OCPD. One hundred ten students of Ferdowsi University of Mashhad and non-student participants were tested by Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II), among whom 18 (mean age = 29.55; SD = 5.26; 84% female) met the criteria for OCPD classification; controls were 20 persons (mean age = 27.85; SD = 5.26; female = 84%), who did not met the OCPD criteria. Both groups were tested on a modified Flicker task for two dimensions of visual performance (i.e., visual acuity: detecting the location of change, complexity, and size; and visual contrast sensitivity). The OCPD group had responded more accurately on pairs related to size, complexity, and contrast, but spent more time to detect a change on pairs related to complexity and contrast. The OCPD individuals seem to have more accurate visual performance than non-OCPD controls. The findings support the relationship between personality characteristics and visual performance within the framework of top-down processing model. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  18. Evaluation of multimodal feedback effects on improving rowing competencies

    Directory of Open Access Journals (Sweden)

    Korman Maria

    2011-12-01

    Full Text Available This study focused on the selection and preliminary evaluation of different types of modal and information feedback in virtual environment to facilitate acquisition and transfer of a complex motor-cognitive skill of rowing. Specifically, we addressed the effectiveness of immediate information feedback provided visually as compared to sensory haptic feedback on the improvement in hands kinematics and changes in cognitive load during the course of learning the basic rowing technique. Several pilot experiments described in this report lead to the evaluation and optimization of the training protocol, to enhance facilitatory effects of adding visual and haptic feedback during training.

  19. Vibrotactile Feedback for Brain-Computer Interface Operation

    OpenAIRE

    Cincotti, Febo; Kauhanen, Laura; Aloise, Fabio; Palomäki, Tapio; Caporusso, Nicholas; Jylänki, Pasi; Mattia, Donatella; Babiloni, Fabio; Vanacker, Gerolf; Nuttin, Marnix; Marciani, Maria Grazia; Millán, José del R.

    2007-01-01

    To be correctly mastered, brain-computer interfaces (BCIs) need an uninterrupted flow of feedback to the user. This feedback is usually delivered through the visual channel. Our aim was to explore the benefits of vibrotactile feedback during users' training and control of EEG-based BCI applications. A protocol for delivering vibrotactile feedback, including specific hardware and software arrangements, was specified. In three studies with 33 subjects (i...

  20. Distinct GABAergic targets of feedforward and feedback connections between lower and higher areas of rat visual cortex.

    Science.gov (United States)

    Gonchar, Yuri; Burkhalter, Andreas

    2003-11-26

    Processing of visual information is performed in different cortical areas that are interconnected by feedforward (FF) and feedback (FB) pathways. Although FF and FB inputs are excitatory, their influences on pyramidal neurons also depend on the outputs of GABAergic neurons, which receive FF and FB inputs. Rat visual cortex contains at least three different families of GABAergic neurons that express parvalbumin (PV), calretinin (CR), and somatostatin (SOM) (Gonchar and Burkhalter, 1997). To examine whether pathway-specific inhibition (Shao and Burkhalter, 1996) is attributable to distinct connections with GABAergic neurons, we traced FF and FB inputs to PV, CR, and SOM neurons in layers 1-2/3 of area 17 and the secondary lateromedial area in rat visual cortex. We found that in layer 2/3 maximally 2% of FF and FB inputs go to CR and SOM neurons. This contrasts with 12-13% of FF and FB inputs onto layer 2/3 PV neurons. Unlike inputs to layer 2/3, connections to layer 1, which contains CR but lacks SOM and PV somata, are pathway-specific: 21% of FB inputs go to CR neurons, whereas FF inputs to layer 1 and its CR neurons are absent. These findings suggest that FF and FB influences on layer 2/3 pyramidal neurons mainly involve disynaptic connections via PV neurons that control the spike outputs to axons and proximal dendrites. Unlike FF input, FB input in addition makes a disynaptic link via CR neurons, which may influence the excitability of distal pyramidal cell dendrites in layer 1.

  1. Using a Feedback Environment to Improve Creative Performance: A Dynamic Affect Perspective

    OpenAIRE

    Gong, Zhenxing; Zhang, Na

    2017-01-01

    Prior research on feedback and creative performance has neglected the dynamic nature of affect and has focused only on the influence of positive affect. We argue that creative performance is the result of a dynamic process in which a person experiences a phase of negative affect and subsequently enters a state of high positive affect that is influenced by the feedback environment. Hierarchical regression was used to analyze a sample of 264 employees from seven industry firms. The results indi...

  2. Vision and laterality: does occlusion disclose a feedback processing advantage for the right hand system?

    Science.gov (United States)

    Buekers, M J; Helsen, W F

    2000-09-01

    The main purpose of this study was to examine whether manual asymmetries could be related to the superiority of the left hemisphere/right hand system in processing visual feedback. Subjects were tested when performing single (Experiment 1) and reciprocal (Experiment 2) aiming movements under different vision conditions (full vision, 20 ms on/180 ms off, 10/90, 40/160, 20/80, 60/120, 20/40). Although in both experiments right hand advantages were found, manual asymmetries did not interact with intermittent vision conditions. Similar patterns of results were found across vision conditions for both hands. These data do not support the visual feedback processing hypothesis of manual asymmetry. Motor performance is affected to the same extent for both hand systems when vision is degraded.

  3. Tactile feedback improves auditory spatial localization

    Directory of Open Access Journals (Sweden)

    Monica eGori

    2014-10-01

    Full Text Available Our recent studies suggest that congenitally blind adults have severely impaired thresholds in an auditory spatial-bisection task, pointing to the importance of vision in constructing complex auditory spatial maps (Gori et al., 2014. To explore strategies that may improve the auditory spatial sense in visually impaired people, we investigated the impact of tactile feedback on spatial auditory localization in 48 blindfolded sighted subjects. We measured auditory spatial bisection thresholds before and after training, either with tactile feedback, verbal feedback or no feedback. Audio thresholds were first measured with a spatial bisection task: subjects judged whether the second sound of a three sound sequence was spatially closer to the first or the third sound. The tactile-feedback group underwent two audio-tactile feedback sessions of 100 trials, where each auditory trial was followed by the same spatial sequence played on the subject’s forearm; auditory spatial bisection thresholds were evaluated after each session. In the verbal-feedback condition, the positions of the sounds were verbally reported to the subject after each feedback trial. The no-feedback group did the same sequence of trials, with no feedback. Performance improved significantly only after audio-tactile feedback. The results suggest that direct tactile feedback interacts with the auditory spatial localization system, possibly by a process of cross-sensory recalibration. Control tests with the subject rotated suggested that this effect occurs only when the tactile and acoustic sequences are spatially coherent. Our results suggest that the tactile system can be used to recalibrate the auditory sense of space. These results encourage the possibility of designing rehabilitation programs to help blind persons establish a robust auditory sense of space, through training with the tactile modality.

  4. DIRECT CORRECTIVE FEEDBACK ON STUDENTS‟WRITING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Testiana Deni Wijayatiningsih

    2017-04-01

    Full Text Available Teaching writing genre especially recount, narrative, and descriptive need brief and detail correction. Moreover, students aware about their mistakes in writing genre clearly. So, they can revise themselves. Based on the background above, this research aimed to know students‘achievement differences between using direct corrective feedback and indirect corrective feedback. The subject of this research was the fourth semester of English Department of Universitas Muhammadiyah Semarang. It employed quasi experiment and one group pre test post test design to analyze the students‘ writing achievement. The result showed that there is a significant differences between direct corrective feedback and indirect corrective feedback. Hopefully this research gives benefit for lecturers to use direct corrective feedback in their teaching writing process .

  5. Prescribed Performance Fuzzy Adaptive Output-Feedback Control for Nonlinear Stochastic Systems

    Directory of Open Access Journals (Sweden)

    Lili Zhang

    2014-01-01

    Full Text Available A prescribed performance fuzzy adaptive output-feedback control approach is proposed for a class of single-input and single-output nonlinear stochastic systems with unmeasured states. Fuzzy logic systems are used to identify the unknown nonlinear system, and a fuzzy state observer is designed for estimating the unmeasured states. Based on the backstepping recursive design technique and the predefined performance technique, a new fuzzy adaptive output-feedback control method is developed. It is shown that all the signals of the resulting closed-loop system are bounded in probability and the tracking error remains an adjustable neighborhood of the origin with the prescribed performance bounds. A simulation example is provided to show the effectiveness of the proposed approach.

  6. Influence of Strategies-Based Feedback in Students' Oral Performance

    Science.gov (United States)

    Sisquiarco, Angie; Rojas, Santiago Sánchez; Abad, José Vicente

    2018-01-01

    This article reports on an action research study that assessed the influence of cognitive and metacognitive strategies-based feedback in the oral performance of a group of 6th grade students at a public school in Medellin, Colombia. Researchers analyzed students' oral performance through assessment and self-assessment rubrics, applied inventories…

  7. Cortical feedback signals generalise across different spatial frequencies of feedforward inputs.

    Science.gov (United States)

    Revina, Yulia; Petro, Lucy S; Muckli, Lars

    2017-09-22

    Visual processing in cortex relies on feedback projections contextualising feedforward information flow. Primary visual cortex (V1) has small receptive fields and processes feedforward information at a fine-grained spatial scale, whereas higher visual areas have larger, spatially invariant receptive fields. Therefore, feedback could provide coarse information about the global scene structure or alternatively recover fine-grained structure by targeting small receptive fields in V1. We tested if feedback signals generalise across different spatial frequencies of feedforward inputs, or if they are tuned to the spatial scale of the visual scene. Using a partial occlusion paradigm, functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis (MVPA) we investigated whether feedback to V1 contains coarse or fine-grained information by manipulating the spatial frequency of the scene surround outside an occluded image portion. We show that feedback transmits both coarse and fine-grained information as it carries information about both low (LSF) and high spatial frequencies (HSF). Further, feedback signals containing LSF information are similar to feedback signals containing HSF information, even without a large overlap in spatial frequency bands of the HSF and LSF scenes. Lastly, we found that feedback carries similar information about the spatial frequency band across different scenes. We conclude that cortical feedback signals contain information which generalises across different spatial frequencies of feedforward inputs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

    Science.gov (United States)

    Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

    2015-01-01

    Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

  9. Auditory feedback and memory for music performance: sound evidence for an encoding effect.

    Science.gov (United States)

    Finney, Steven A; Palmer, Caroline

    2003-01-01

    Research on the effects of context and task on learning and memory has included approaches that emphasize processes during learning (e.g., Craik & Tulving, 1975) and approaches that emphasize a match of conditions during learning with conditions during a later test of memory (e.g., Morris, Bransford, & Franks, 1977; Proteau, 1992; Tulving & Thomson, 1973). We investigated the effects of auditory context on learning and retrieval in three experiments on memorized music performance (a form of serial recall). Auditory feedback (presence or absence) was manipulated while pianists learned musical pieces from notation and when they later played the pieces from memory. Auditory feedback during learning significantly improved later recall. However, auditory feedback at test did not significantly affect recall, nor was there an interaction between conditions at learning and test. Auditory feedback in music performance appears to be a contextual factor that affects learning but is relatively independent of retrieval conditions.

  10. The Importance of Visual Feedback Design in BCIs; from Embodiment to Motor Imagery Learning.

    Science.gov (United States)

    Alimardani, Maryam; Nishio, Shuichi; Ishiguro, Hiroshi

    2016-01-01

    Brain computer interfaces (BCIs) have been developed and implemented in many areas as a new communication channel between the human brain and external devices. Despite their rapid growth and broad popularity, the inaccurate performance and cost of user-training are yet the main issues that prevent their application out of the research and clinical environment. We previously introduced a BCI system for the control of a very humanlike android that could raise a sense of embodiment and agency in the operators only by imagining a movement (motor imagery) and watching the robot perform it. Also using the same setup, we further discovered that the positive bias of subjects' performance both increased their sensation of embodiment and improved their motor imagery skills in a short period. In this work, we studied the shared mechanism between the experience of embodiment and motor imagery. We compared the trend of motor imagery learning when two groups of subjects BCI-operated different looking robots, a very humanlike android's hands and a pair of metallic gripper. Although our experiments did not show a significant change of learning between the two groups immediately during one session, the android group revealed better motor imagery skills in the follow up session when both groups repeated the task using the non-humanlike gripper. This result shows that motor imagery skills learnt during the BCI-operation of humanlike hands are more robust to time and visual feedback changes. We discuss the role of embodiment and mirror neuron system in such outcome and propose the application of androids for efficient BCI training.

  11. The Importance of Visual Feedback Design in BCIs; from Embodiment to Motor Imagery Learning.

    Directory of Open Access Journals (Sweden)

    Maryam Alimardani

    Full Text Available Brain computer interfaces (BCIs have been developed and implemented in many areas as a new communication channel between the human brain and external devices. Despite their rapid growth and broad popularity, the inaccurate performance and cost of user-training are yet the main issues that prevent their application out of the research and clinical environment. We previously introduced a BCI system for the control of a very humanlike android that could raise a sense of embodiment and agency in the operators only by imagining a movement (motor imagery and watching the robot perform it. Also using the same setup, we further discovered that the positive bias of subjects' performance both increased their sensation of embodiment and improved their motor imagery skills in a short period. In this work, we studied the shared mechanism between the experience of embodiment and motor imagery. We compared the trend of motor imagery learning when two groups of subjects BCI-operated different looking robots, a very humanlike android's hands and a pair of metallic gripper. Although our experiments did not show a significant change of learning between the two groups immediately during one session, the android group revealed better motor imagery skills in the follow up session when both groups repeated the task using the non-humanlike gripper. This result shows that motor imagery skills learnt during the BCI-operation of humanlike hands are more robust to time and visual feedback changes. We discuss the role of embodiment and mirror neuron system in such outcome and propose the application of androids for efficient BCI training.

  12. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    International Nuclear Information System (INIS)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Karatzas, L S

    2009-01-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  13. Performance limitations of piezoelectric and force feedback electrostatic transducers in different applications

    Energy Technology Data Exchange (ETDEWEB)

    Hadjiloucas, S; Walker, G C; Bowen, J W [Cybernetics, School of Systems Engineering, University of Reading, RG6 6AY (United Kingdom); Karatzas, L S, E-mail: s.hadjiloucas@reading.ac.u [Temasek Polytechnic, School of Engineering, 21 Tampines Avenue 1, Singapore, 529757 (Singapore)

    2009-07-01

    Current limitations in piezoelectric and electrostatic transducers are discussed. A force-feedback electrostatic transducer capable of operating at bandwidths up to 20 kHz is described. Advantages of the proposed design are a linearised operation which simplifies the feedback control aspects and robustness of the performance characteristics to environmental perturbations. Applications in nanotechnology, optical sciences and acoustics are discussed.

  14. Noisy visual feedback training impairs detection of self-generated movement error: implications for anosognosia for hemiplegia

    Directory of Open Access Journals (Sweden)

    Catherine ePreston

    2014-06-01

    Full Text Available Anosognosia for hemiplegia (AHP is characterised as a disorder in which patients are unaware of their contralateral motor deficit. Many current theories for unawareness in AHP are based on comparator model accounts of the normal experience of agency. According to such models, while small mismatches between predicted and actual feedback allow unconscious fine-tuning of normal actions, mismatches that surpass an inherent threshold reach conscious awareness and inform judgements of agency (whether a given movement is produced by the self or another agent. This theory depends on a threshold for consciousness that is greater than the intrinsic noise in the system to reduce the occurrence of incorrect rejections of self-generated movements and maintain a fluid experience of agency. Pathological increases to this threshold could account for reduced motor awareness following brain injury, including AHP. The current experiment tested this hypothesis in healthy controls by exposing them to training in which noise was applied the visual feedback of their normal reaches. Subsequent self/other attribution tasks without noise revealed a decrease in the ability to detect manipulated (other feedback compared to training without noise. This suggests a slackening of awareness thresholds in the comparator model that may help to explain clinical observations of decreased action awareness following stroke.

  15. Interação de variáveis biomecânicas na composição de "feedback" visual aumentado para o ensino do ciclismo Interacción de variables biomecánicas en la composición de feedback visual aumentado para el enseñanza del ciclismo Interaction of biomechanical variables in the composition of visual augmented feedback for learning cycling

    Directory of Open Access Journals (Sweden)

    Guilherme Garcia Holderbaum

    2012-12-01

    Full Text Available O objetivo deste estudo foi testar uma metodologia para o ensino da técnica da pedalada do ciclismo utilizando variáveis biomecánicas para desenvolver um sistema de "feedback" visual aumentado (FVA. Participaram do estudo 19 indivíduos, sem experiência no ciclismo , divididos em grupo experimental (n = 10 e controle (n = 9. Inicialmente foi realizado um pré-teste para determinar o consumo máximo de oxigênio (VO2máx bem como a carga de trabalho utilizada nas sessões práticas que correspondeu a 60% do VO2máx. Em seguida foram realizadas sete sessões de prática. O grupo experimental foi submetido ao FVA e o grupo controle ao "feedback" aumentado (FA. O teste de retenção mostrou um aumento de 21 % na média do índice de efetividade (IE do grupo experimental quando comparado ao grupo controle. Os resultados mostraram que variáveis biomecánicas são apropriadas para o desenvolvimento de FVA e podem contribuir no processo de ensino-aprendizagem da técnica da pedalada do ciclismo.El objetivo de este estudio fue probar una metodología para enseñar la técnica de el ciclismo mediante la utilización de variables biomecánicas para desarrollar un sistema de feedback visual aumentado (FVA. Fue aplicado en 19 personas sin experiencia en el ciclismo, divididos en dos grupos (experimental = 10 y control = 9. Inicialmente se realizó un pre-test para determinar el consumo máximo de oxígeno (VO2max y la carga de trabajo utilizada en las sesiones de práctica que correspondía al 60% del VO2máx. El grupo experimental fue sometido a la FVA y el control a la feedback aumentado (FA. El ensayo de retención mostró un aumento del 21% en la media del índice de eficacia (IE en el grupo experimental en comparación con el grupo control. Los resultados mostraron que las variables biomecánicas son apropiadas para el desarrollo de la FVA y puede contribuir al proceso de enseñanza y aprendizaje del ciclismo.The aim of this study was to test a

  16. The Effects of Mirror Feedback during Target Directed Movements on Ipsilateral Corticospinal Excitability

    Directory of Open Access Journals (Sweden)

    Mathew Yarossi

    2017-05-01

    Full Text Available Mirror visual feedback (MVF training is a promising technique to promote activation in the lesioned hemisphere following stroke, and aid recovery. However, current outcomes of MVF training are mixed, in part, due to variability in the task undertaken during MVF. The present study investigated the hypothesis that movements directed toward visual targets may enhance MVF modulation of motor cortex (M1 excitability ipsilateral to the trained hand compared to movements without visual targets. Ten healthy subjects participated in a 2 × 2 factorial design in which feedback (veridical, mirror and presence of a visual target (target present, target absent for a right index-finger flexion task were systematically manipulated in a virtual environment. To measure M1 excitability, transcranial magnetic stimulation (TMS was applied to the hemisphere ipsilateral to the trained hand to elicit motor evoked potentials (MEPs in the untrained first dorsal interosseous (FDI and abductor digiti minimi (ADM muscles at rest prior to and following each of four 2-min blocks of 30 movements (B1–B4. Targeted movement kinematics without visual feedback was measured before and after training to assess learning and transfer. FDI MEPs were decreased in B1 and B2 when movements were made with veridical feedback and visual targets were absent. FDI MEPs were decreased in B2 and B3 when movements were made with mirror feedback and visual targets were absent. FDI MEPs were increased in B3 when movements were made with mirror feedback and visual targets were present. Significant MEP changes were not present for the uninvolved ADM, suggesting a task-specific effect. Analysis of kinematics revealed learning occurred in visual target-directed conditions, but transfer was not sensitive to mirror feedback. Results are discussed with respect to current theoretical mechanisms underlying MVF-induced changes in ipsilateral excitability.

  17. Investigating the role of feedback and motivation in clinical reaction time assessment.

    Science.gov (United States)

    Eckner, James T; Chandran, Srikrishna; Richardson, James K

    2011-12-01

    To investigate the influence of performance feedback and motivation during 2 tests of simple visuomotor reaction time (RT). Cross-sectional, observational study. Outpatient academic physiatry clinic. Thirty-one healthy adults (mean [SD], 54 ± 15 years). Participants completed a clinical test of RT (RT(clin)) and a computerized test of RT with and without performance feedback (RT(compFB) and RT(compNoFB), respectively) in randomly assigned order. They then ranked their degree of motivation during each test. RT(clin) measured the time required to catch a suspended vertical shaft by hand closure after release of the shaft by the examiner. RT(compFB) and RT(compNoFB) both measured the time required to press a computer key in response to a visual cue displayed on a computer monitor. Performance feedback (visual display of the previous trial and summary results) was provided for RT(compFB), but not for RT(compNoFB). Means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) and participants' self-reported motivation on a 5-point Likert scale for each test. There were significant differences in both the means and standard deviations of RT(clin), RT(compFB), and RT(compNoFB) (F(2,60) = 81.66, P motivation between RT(clin) and RT(compFB), both of which were reported to be more motivating than RT(compNoFB). The stronger correlation between RT(clin) and RT(compFB) as well as the higher reported motivation during RT(clin) and RT(compFB) testing suggest that performance feedback is a positive motivating factor that is inherent to RT(clin) testing. RT(clin) is a simple, inexpensive technique for measuring RT and appears to be an intrinsically motivating task. This motivation may promote faster, more consistent RT performance compared with currently available computerized programs, which do not typically provide performance feedback. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  18. Feedback from performance assessment to site characterisation. The SITE-94 example

    International Nuclear Information System (INIS)

    Dverstorp, B.; Geier, J.

    1999-01-01

    Interaction and information exchange between site characterisation and performance assessment are key features of any successful radioactive waste management programme. Some examples are presented of the types of feedback that can be offered from performance assessment to site characterisation, based on SKI's most recent performance assessment project, SITE-94. SITE-94 in Sweden was an assessment of a hypothetical repository for spent nuclear fuel, based on real data gathered in the surface-based investigation of the Aespoe Hard Rock Laboratory site. Examples of feedback are given concerning quality control of data and site investigation procedures, identification of key parameters for the performance assessment, use of models for planning and evaluation of a site investigation, data sampling strategies, and guidance on future priorities for further development of site investigation methods. Because site characterisation serves multiple purposes, including provision of data for repository design and construction, it must account for and compromise among requirements from several lines of analyses in the performance assessment. (author)

  19. Cloud-based Networked Visual Servo Control

    OpenAIRE

    Wu, Haiyan; Lu, Lei; Chen, Chih-Chung; Hirche, Sandra; Kühnlenz, Kolja

    2013-01-01

    The performance of vision-based control systems, in particular of highly dynamic vision-based motion control systems, is often limited by the low sampling rate of the visual feedback caused by the long image processing time. In order to overcome this problem, the networked visual servo control, which integrates networked computational resources for cloud image processing, is considered in this article. The main contributions of this article are i) a real-time transport protocol for transmitti...

  20. Improving lower limb weight distribution asymmetry during the squat using Nintendo Wii Balance Boards and real-time feedback.

    Science.gov (United States)

    McGough, Rian; Paterson, Kade; Bradshaw, Elizabeth J; Bryant, Adam L; Clark, Ross A

    2012-01-01

    Weight-bearing asymmetry (WBA) may be detrimental to performance and could increase the risk of injury; however, detecting and reducing it is difficult in a field setting. This study assessed whether a portable and simple-to-use system designed with multiple Nintendo Wii Balance Boards (NWBBs) and customized software can be used to evaluate and improve WBA. Fifteen elite Australian Rules Footballers and 32 age-matched, untrained participants were tested for measures of WBA while squatting. The NWBB and customized software provided real-time visual feedback of WBA during half of the trials. Outcome measures included the mean mass difference (MMD) between limbs, interlimb symmetry index (SI), and percentage of time spent favoring a single limb (TFSL). Significant reductions in MMD (p = 0.028) and SI (p = 0.007) with visual feedback were observed for the entire group data. Subgroup analysis revealed significant reductions in MMD (p = 0.047) and SI (p = 0.026) with visual feedback in the untrained sample; however, the reductions in the trained sample were nonsignificant. The trained group showed significantly less WBA for TFSL under both visual conditions (no feedback: p = 0.015, feedback: p = 0.017). Correlation analysis revealed that participants with high levels of WBA had the greatest response to feedback (p professional athletes do not possess the same magnitude of WBA. Inexpensive, portable, and widely available gaming technology may be used to evaluate and improve WBA in clinical and sporting settings.

  1. Automatic medical image annotation and keyword-based image retrieval using relevance feedback.

    Science.gov (United States)

    Ko, Byoung Chul; Lee, JiHyeon; Nam, Jae-Yeal

    2012-08-01

    This paper presents novel multiple keywords annotation for medical images, keyword-based medical image retrieval, and relevance feedback method for image retrieval for enhancing image retrieval performance. For semantic keyword annotation, this study proposes a novel medical image classification method combining local wavelet-based center symmetric-local binary patterns with random forests. For keyword-based image retrieval, our retrieval system use the confidence score that is assigned to each annotated keyword by combining probabilities of random forests with predefined body relation graph. To overcome the limitation of keyword-based image retrieval, we combine our image retrieval system with relevance feedback mechanism based on visual feature and pattern classifier. Compared with other annotation and relevance feedback algorithms, the proposed method shows both improved annotation performance and accurate retrieval results.

  2. Learning receptive fields using predictive feedback.

    Science.gov (United States)

    Jehee, Janneke F M; Rothkopf, Constantin; Beck, Jeffrey M; Ballard, Dana H

    2006-01-01

    Previously, it was suggested that feedback connections from higher- to lower-level areas carry predictions of lower-level neural activities, whereas feedforward connections carry the residual error between the predictions and the actual lower-level activities [Rao, R.P.N., Ballard, D.H., 1999. Nature Neuroscience 2, 79-87.]. A computational model implementing the hypothesis learned simple cell receptive fields when exposed to natural images. Here, we use predictive feedback to explain tuning properties in medial superior temporal area (MST). We implement the hypothesis using a new, biologically plausible, algorithm based on matching pursuit, which retains all the features of the previous implementation, including its ability to efficiently encode input. When presented with natural images, the model developed receptive field properties as found in primary visual cortex. In addition, when exposed to visual motion input resulting from movements through space, the model learned receptive field properties resembling those in MST. These results corroborate the idea that predictive feedback is a general principle used by the visual system to efficiently encode natural input.

  3. Computerized evaluation of deambulatory pattern before and after visual rehabilitation treatment performed with biofeedback in visually impaired patients suffering from macular degeneration

    Directory of Open Access Journals (Sweden)

    Fernanda Pacella

    2016-09-01

    Full Text Available Aims: The aim of this study was double: the primary endpoint was to evaluate the efficacy of visual rehabilitation of visually impaired patients with macular degeneration (AMD. The secondary endpoint was to assess the effect of rehabilitation treatment on the ambulatory pattern using a computerized evaluation of walking, focusing the attention on space-time parameters that are influenced in patients with visual impairment. Methods: 10 patients with AMD were enrolled, 6 males and 4 females, and examined 15 eyes, at Department of Sense Organs, Faculty of Medicine and Dentistry Sapienza University of Rome, Italy. Visual rehabilitation was carried out with the use of a microperimeter MP1 using the examination of biofeedback. Patients are asked to move their eyes in coordination with an audible feedback that alerts the patient when he is setting properly the fixation target previously selected. All patients were subjected to 10 sessions lasting 15 minutes each for each eye, 1 time per week. The best corrected visual acuity (BCVA was assessed by far with the ETDRS optotype IN LOG MAR, and by close to 25 cm by adding + 4 ball (addition to near to the BCVA. For each eye the PB ( print body on the distance of 25 cm was measured; It fixation stability for 30 seconds was examined by microperimeter. Gait Analysis was performed with system ELITE BTS SpA (Milan, Italy. Results: At the end of the rehabilitation treatment with biofeedback it was found a marked improvement in BCVA. The BCVA before the rehabilitation treatment was ETDRS 12 LETTERS = 0.86 logMAR. At the end of the visual rehabilitation 16 LETTERS = 0.78 logMAR. The near visual acuity presented a decrease of the printer body measurement (PB and a statistically significant improvement in the fixation stability. Analysis of the spatial and temporal parameters of gait cycle, aimed at assessing the global aspects of gait (speed, rhythm, symmetry, fluidity, dynamic balance showed no significant changes

  4. Piloting the feasibility of head-mounted video technology to augment student feedback during simulated clinical decision-making: An observational design pilot study.

    Science.gov (United States)

    Forbes, Helen; Bucknall, Tracey K; Hutchinson, Alison M

    2016-04-01

    Clinical decision-making is a complex activity that is critical to patient safety. Simulation, augmented by feedback, affords learners the opportunity to learn critical clinical decision-making skills. More detailed feedback following simulation exercises has the potential to further enhance student learning, particularly in relation to developing improved clinical decision-making skills. To investigate the feasibility of head-mounted video camera recordings, to augment feedback, following acute patient deterioration simulations. Pilot study using an observational design. Ten final-year nursing students participated in three simulation exercises, each focussed on detection and management of patient deterioration. Two observers collected behavioural data using an adapted version of Gaba's Clinical Simulation Tool, to provide verbal feedback to each participant, following each simulation exercise. Participants wore a head-mounted video camera during the second simulation exercise only. Video recordings were replayed to participants to augment feedback, following the second simulation exercise. Data were collected on: participant performance (observed and perceived); participant perceptions of feedback methods; and head-mounted video camera recording feasibility and capability for detailed audio-visual feedback. Management of patient deterioration improved for six participants (60%). Increased perceptions of confidence (70%) and competence (80%), were reported by the majority of participants. Few participants (20%) agreed that the video recording specifically enhanced their learning. The visual field of the head-mounted video camera was not always synchronised with the participant's field of vision, thus affecting the usefulness of some recordings. The usefulness of the video recordings, to enhance verbal feedback to participants on detection and management of simulated patient deterioration, was inconclusive. Modification of the video camera glasses, to improve

  5. Performance Feedback Utility in a Small Organization: Effects on Organizational Outcomes and Managerial Decision Processes.

    Science.gov (United States)

    Florin-Thuma, Beth C.; Boudreau, John W.

    1987-01-01

    Investigated the frequent but previously untested assertion that utility analysis can improve communication and decision making about human resource management programs by examining a performance feedback intervention in a small fast-food store. Results suggest substantial payoffs from performance feedback, though the store's owner-managers had…

  6. Social dimension and complexity differentially influence brain responses during feedback processing.

    Science.gov (United States)

    Pfabigan, Daniela M; Gittenberger, Marianne; Lamm, Claus

    2017-10-30

    Recent research emphasizes the importance of social factors during performance monitoring. Thus, the current study investigated the impact of social stimuli -such as communicative gestures- on feedback processing. Moreover, it addressed a shortcoming of previous studies, which failed to consider stimulus complexity as potential confounding factor. Twenty-four volunteers performed a time estimation task while their electroencephalogram was recorded. Either social complex, social non-complex, non-social complex, or non-social non-complex stimuli were used to provide performance feedback. No effects of social dimension or complexity were found for task performance. In contrast, Feedback-Related Negativity (FRN) and P300 amplitudes were sensitive to both factors, with larger FRN and P300 amplitudes after social compared to non-social stimuli, and larger FRN amplitudes after complex positive than non-complex positive stimuli. P2 amplitudes were solely sensitive to feedback valence and social dimension. Subjectively, social complex stimuli were rated as more motivating than non-social complex ones. Independently of each other, social dimension and visual complexity influenced amplitude variation during performance monitoring. Social stimuli seem to be perceived as more salient, which is corroborated by P2, FRN and P300 results, as well as by subjective ratings. This could be explained due to their given relevance during every day social interactions.

  7. The role of organizational insiders' developmental feedback and proactive personality on newcomers' performance: an interactionist perspective.

    Science.gov (United States)

    Li, Ning; Harris, T Brad; Boswell, Wendy R; Xie, Zhitao

    2011-11-01

    Drawing from an interactionist approach and feedback research, we examine the role of developmental feedback and proactive personality on newcomer task performance and helping behavior. Data were collected from 2 high-tech joint-ventures within the information technology and manufacturing industries located in Shanghai, China. Results based on 151 newcomer-manager dyads showed that supervisor developmental feedback (SDF) positively related to newcomer helping behavior and that SDF and coworker developmental feedback interactively predicted newcomer task performance. We also found differential moderating effects of proactive personality: SDF more strongly related to helping behavior when proactive personality was lower; conversely, coworker developmental feedback more strongly related to helping behavior when proactive personality was higher. (c) 2011 APA, all rights reserved.

  8. Cycling in the Absence of Task-related Feedback: Effects on Pacing and Performance

    Directory of Open Access Journals (Sweden)

    Benjamin Smits

    2016-08-01

    Full Text Available Introduction. To achieve personal goals in exercise task completion, exercisers have to regulate, distribute and manage their effort. In endurance sports, it has become very commonplace for athletes to consult task-related feedback on external devices to do so. The aim of the present study was to explore the importance of the presence of this information by examining the influence of the absence of commonly available task-related feedback on effort distribution and performance in experienced endurance athletes.Methods. A 20-km cycling time trial was performed. 20 Participants from a homogenous cyclist population were appointed to a group that did not receive any feedback (NoF, or a group that could consult task-related feedback (i.e., speed, heart rate, power output, cadence, elapsed time and elapsed distance continuously during their trial (FF.Results. The distribution of power output (PO differed between groups. Most evident is the spurt at the end of the trial of FF, which was not incorporated by NoF. Nevertheless, no between-group differences were found in performance time (FF: 28.86 +/- 3.68 min vs. NoF: 30.95 +/- 2.77 min and mean PO controlled by body mass (FF: 3.61 +/- .60 W/kg vs. NoF: 3.43 +/- .38 W/kg. Also, no differences in rating of perceived exertion scores were found.Conclusion. The current study provides a first indication that prior knowledge of task demands together with reliance on bodily and environmental information can be sufficient for experienced athletes to come to comparable time trial performances. This questions the necessity of the presence of in-race instantaneous task-related feedback via external devices for maximising performance. Moreover, it seems that different pacing strategies emerge depending on sources of information available to experienced athletes.

  9. Performance improvements from imagery:evidence that internal visual imagery is superior to external visual imagery for slalom performance

    Directory of Open Access Journals (Sweden)

    Nichola eCallow

    2013-10-01

    Full Text Available We report three experiments investigating the hypothesis that use of internal visual imagery (IVI would be superior to external visual imagery (EVI for the performance of different slalom-based motor tasks. In Experiment 1, three groups of participants (IVI, EVI, and a control group performed a driving-simulation slalom task. The IVI group achieved significantly quicker lap times than EVI and the control group. In Experiment 2, participants performed a downhill running slalom task under both IVI and EVI conditions. Performance was again quickest in the IVI compared to EVI condition, with no differences in accuracy. Experiment 3 used the same group design as Experiment 1, but with participants performing a downhill ski-slalom task. Results revealed the IVI group to be significantly more accurate than the control group, with no significant differences in time taken to complete the task. These results support the beneficial effects of IVI for slalom-based tasks, and significantly advances our knowledge related to the differential effects of visual imagery perspectives on motor performance.

  10. Timing matters: The impact of immediate and delayed feedback on artificial language learning

    Directory of Open Access Journals (Sweden)

    Bertram Opitz

    2011-02-01

    Full Text Available In the present experiment, we used event-related potentials (ERP to investigate the role of immediate and delayed feedback in an artificial grammar learning task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of one second. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP elicited by positive feedback only. The feedback-related negativity (FRN, however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for artificial grammar learning as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.

  11. We're All in This Together Now: Group Performance Feedback to Increase Classroom Team Data Collection

    Science.gov (United States)

    Pellecchia, Melanie; Connell, James E.; Eisenhart, Donald; Kane, Meghan; Schoener, Christine; Turkel, Kimberly; Riley, Megan; Mandell, David S.

    2011-01-01

    This study's primary goal was to evaluate the use of performance feedback procedures delivered to a classroom team to increase daily data collection. Performance feedback (PFB) was delivered to four classroom teams responsible for the daily collection of data representing student performance during prescribed instructional activities. Using a…

  12. Closed-Loop Hybrid Gaze Brain-Machine Interface Based Robotic Arm Control with Augmented Reality Feedback

    Directory of Open Access Journals (Sweden)

    Hong Zeng

    2017-10-01

    Full Text Available Brain-machine interface (BMI can be used to control the robotic arm to assist paralysis people for performing activities of daily living. However, it is still a complex task for the BMI users to control the process of objects grasping and lifting with the robotic arm. It is hard to achieve high efficiency and accuracy even after extensive trainings. One important reason is lacking of sufficient feedback information for the user to perform the closed-loop control. In this study, we proposed a method of augmented reality (AR guiding assistance to provide the enhanced visual feedback to the user for a closed-loop control with a hybrid Gaze-BMI, which combines the electroencephalography (EEG signals based BMI and the eye tracking for an intuitive and effective control of the robotic arm. Experiments for the objects manipulation tasks while avoiding the obstacle in the workspace are designed to evaluate the performance of our method for controlling the robotic arm. According to the experimental results obtained from eight subjects, the advantages of the proposed closed-loop system (with AR feedback over the open-loop system (with visual inspection only have been verified. The number of trigger commands used for controlling the robotic arm to grasp and lift the objects with AR feedback has reduced significantly and the height gaps of the gripper in the lifting process have decreased more than 50% compared to those trials with normal visual inspection only. The results reveal that the hybrid Gaze-BMI user can benefit from the information provided by the AR interface, improving the efficiency and reducing the cognitive load during the grasping and lifting processes.

  13. Closed-Loop Hybrid Gaze Brain-Machine Interface Based Robotic Arm Control with Augmented Reality Feedback

    Science.gov (United States)

    Zeng, Hong; Wang, Yanxin; Wu, Changcheng; Song, Aiguo; Liu, Jia; Ji, Peng; Xu, Baoguo; Zhu, Lifeng; Li, Huijun; Wen, Pengcheng

    2017-01-01

    Brain-machine interface (BMI) can be used to control the robotic arm to assist paralysis people for performing activities of daily living. However, it is still a complex task for the BMI users to control the process of objects grasping and lifting with the robotic arm. It is hard to achieve high efficiency and accuracy even after extensive trainings. One important reason is lacking of sufficient feedback information for the user to perform the closed-loop control. In this study, we proposed a method of augmented reality (AR) guiding assistance to provide the enhanced visual feedback to the user for a closed-loop control with a hybrid Gaze-BMI, which combines the electroencephalography (EEG) signals based BMI and the eye tracking for an intuitive and effective control of the robotic arm. Experiments for the objects manipulation tasks while avoiding the obstacle in the workspace are designed to evaluate the performance of our method for controlling the robotic arm. According to the experimental results obtained from eight subjects, the advantages of the proposed closed-loop system (with AR feedback) over the open-loop system (with visual inspection only) have been verified. The number of trigger commands used for controlling the robotic arm to grasp and lift the objects with AR feedback has reduced significantly and the height gaps of the gripper in the lifting process have decreased more than 50% compared to those trials with normal visual inspection only. The results reveal that the hybrid Gaze-BMI user can benefit from the information provided by the AR interface, improving the efficiency and reducing the cognitive load during the grasping and lifting processes. PMID:29163123

  14. Duration reproduction with sensory feedback delay: Differential involvement of perception and action time

    Directory of Open Access Journals (Sweden)

    Stephanie eGanzenmüller

    2012-10-01

    Full Text Available Previous research has shown that voluntary action can attract subsequent, delayed feedback events towards the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal-order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration was independent of the delay manipulation.

  15. Visual control improves the accuracy of hand positioning in Huntington’s disease

    Directory of Open Access Journals (Sweden)

    Emilia J. Sitek

    2017-08-01

    Full Text Available Background: The study aimed at demonstrating dependence of visual feedback during hand and finger positioning task performance among Huntington’s disease patients in comparison to patients with Parkinson’s disease and cervical dystonia. Material and methods: Eighty-nine patients participated in the study (23 with Huntington’s disease, 25 with Parkinson’s disease with dyskinesias, 21 with Parkinson’s disease without dyskinesias, and 20 with cervical dystonia, scoring ≥20 points on Mini-Mental State Examination in order to assure comprehension of task instructions. Neurological examination comprised of the motor section from the Unified Huntington’s Disease Rating Scale for Huntington’s disease, the Unified Parkinson’s Disease Rating Scale Part II–IV for Parkinson’s disease and the Toronto Western Spasmodic Torticollis Rating Scale for cervical dystonia. In order to compare hand position accuracy under visually controlled and blindfolded conditions, the patient imitated each of the 10 examiner’s hand postures twice, once under the visual control condition and once with no visual feedback provided. Results: Huntington’s disease patients imitated examiner’s hand positions less accurately under blindfolded condition in comparison to Parkinson’s disease without dyskinesias and cervical dystonia participants. Under visually controlled condition there were no significant inter-group differences. Conclusions: Huntington’s disease patients exhibit higher dependence on visual feedback while performing motor tasks than Parkinson’s disease and cervical dystonia patients. Possible improvement of movement precision in Huntington’s disease with the use of visual cues could be potentially useful in the patients’ rehabilitation.

  16. Frequency and determinants of residents' narrative feedback on the teaching performance of faculty: narratives in numbers

    NARCIS (Netherlands)

    van der Leeuw, Renée M.; Overeem, Karlijn; Arah, Onyebuchi A.; Heineman, Maas Jan; Lombarts, Kiki M. J. M. H.

    2013-01-01

    Physicians involved in residency training often receive feedback from residents on their teaching. Research shows that learners value narrative feedback, but knowledge of the frequency and determinants of narrative feedback in teaching performance evaluation is lacking. This study aims to

  17. Cortical feedback signals generalise across different spatial frequencies of feedforward inputs

    OpenAIRE

    Revina, Yulia; Petro, Lucy S.; Muckli, Lars

    2017-01-01

    Visual processing in cortex relies on feedback projections contextualising feedforward information flow. Primary visual cortex (V1) has small receptive fields and processes feedforward information at a fine-grained spatial scale, whereas higher visual areas have larger, spatially invariant receptive fields. Therefore, feedback could provide coarse information about the global scene structure or alternatively recover fine-grained structure by targeting small receptive fields in V1. We tested i...

  18. Using Screencasts to Enhance Assessment Feedback: Students' Perceptions and Preferences

    Science.gov (United States)

    Marriott, Pru; Teoh, Lim Keong

    2012-01-01

    In the UK, assessment and feedback have been regularly highlighted by the National Student Survey as critical aspects that require improvement. An innovative approach to delivering feedback that has proved successful in non-business-related disciplines is the delivery of audio and visual feedback using screencast technology. The feedback on…

  19. Visual information transfer. 1: Assessment of specific information needs. 2: The effects of degraded motion feedback. 3: Parameters of appropriate instrument scanning behavior

    Science.gov (United States)

    Comstock, J. R., Jr.; Kirby, R. H.; Coates, G. D.

    1984-01-01

    Pilot and flight crew assessment of visually displayed information is examined as well as the effects of degraded and uncorrected motion feedback, and instrument scanning efficiency by the pilot. Computerized flight simulation and appropriate physiological measurements are used to collect data for standardization.

  20. From feedback- to response-based performance monitoring in active and observational learning.

    Science.gov (United States)

    Bellebaum, Christian; Colosio, Marco

    2014-09-01

    Humans can adapt their behavior by learning from the consequences of their own actions or by observing others. Gradual active learning of action-outcome contingencies is accompanied by a shift from feedback- to response-based performance monitoring. This shift is reflected by complementary learning-related changes of two ACC-driven ERP components, the feedback-related negativity (FRN) and the error-related negativity (ERN), which have both been suggested to signal events "worse than expected," that is, a negative prediction error. Although recent research has identified comparable components for observed behavior and outcomes (observational ERN and FRN), it is as yet unknown, whether these components are similarly modulated by prediction errors and thus also reflect behavioral adaptation. In this study, two groups of 15 participants learned action-outcome contingencies either actively or by observation. In active learners, FRN amplitude for negative feedback decreased and ERN amplitude in response to erroneous actions increased with learning, whereas observational ERN and FRN in observational learners did not exhibit learning-related changes. Learning performance, assessed in test trials without feedback, was comparable between groups, as was the ERN following actively performed errors during test trials. In summary, the results show that action-outcome associations can be learned similarly well actively and by observation. The mechanisms involved appear to differ, with the FRN in active learning reflecting the integration of information about own actions and the accompanying outcomes.

  1. The Regulation of Behavioral Plasticity by Performance-Based Feedback and an Experimental Test with Avian Egg Production.

    Science.gov (United States)

    Sockman, Keith W

    2016-05-01

    Optimizing plasticity in behavioral performances requires the abilities to regulate physiological effort and to estimate the effects of the environment. To describe how performance-based feedback could play a role in regulating recursive or continuous behavioral performances, I developed two models, one (environmental feedback) that assumes an initial ability to regulate effort but not to predict the effects of the environment and the other (effort feedback) that assumes an initial ability to predict the effects of the environment but not to regulate effort. I tested them by manipulating feedback on egg production, using an egg-substitution experiment in wild, free-ranging Lincoln's sparrows (Melospiza lincolnii). I discovered that females adjusted the size of their clutches' third laid eggs in response to the size of an experimentally substituted first laid egg, such that the size of the third laid egg increased with the size of the substitute. Results were largely consistent with the environmental feedback model, though small portions of the response surface were consistent with the effort feedback model or with neither. Regardless, such feedback-based regulation predicted by either model may help females maximize net benefits of egg production and may be a basis for mechanisms regulating a wide range of other behavioral performances, as well.

  2. Altered visual strategies and attention are related to increased force fluctuations during a pinch grip task in older adults.

    Science.gov (United States)

    Keenan, Kevin G; Huddleston, Wendy E; Ernest, Bradley E

    2017-11-01

    The purpose of the study was to determine the visual strategies used by older adults during a pinch grip task and to assess the relations between visual strategy, deficits in attention, and increased force fluctuations in older adults. Eye movements of 23 older adults (>65 yr) were monitored during a low-force pinch grip task while subjects viewed three common visual feedback displays. Performance on the Grooved Pegboard test and an attention task (which required no concurrent hand movements) was also measured. Visual strategies varied across subjects and depended on the type of visual feedback provided to the subjects. First, while viewing a high-gain compensatory feedback display (horizontal bar moving up and down with force), 9 of 23 older subjects adopted a strategy of performing saccades during the task, which resulted in 2.5 times greater force fluctuations in those that exhibited saccades compared with those who maintained fixation near the target line. Second, during pursuit feedback displays (force trace moving left to right across screen and up and down with force), all subjects exhibited multiple saccades, and increased force fluctuations were associated ( r s = 0.6; P = 0.002) with fewer saccades during the pursuit task. Also, decreased low-frequency (attention z scores. Comparison of these results with our previously published results in young subjects indicates that saccadic eye movements and attention are related to force control in older adults. NEW & NOTEWORTHY The significant contributions of the study are the addition of eye movement data and an attention task to explain differences in hand motor control across different visual displays in older adults. Older participants used different visual strategies across varying feedback displays, and saccadic eye movements were related with motor performance. In addition, those older individuals with deficits in attention had impaired motor performance on two different hand motor control tasks, including

  3. Introducing artificial depth cues to improve task performance in ITER maintenance actions

    NARCIS (Netherlands)

    Heemskerk, C.J.M.; Eendebak, P.T.; Schropp, G.Y.R.; Hermes, H.V.; Elzendoorn, B.S.Q.; Magielsen, A.J.

    2013-01-01

    Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators

  4. Tune and Orbit feedbacks performance: a user perspective

    CERN Document Server

    Ponce, L

    2012-01-01

    The presentation will present the performance and issues of tune and orbit feedbacks seen from the user (operation) perspective. Some statistics on the beam dumps causes will be presented to emphasize the two main limitations of the system : the issue on the tune measurement and the triggering of the QPS system of RQTs circuits. The possible improvements for 2012 will then be discussed together with the foreseen software changes for the orbit reference management.

  5. The Impact of Feedback Frequency on Learning and Task Performance: Challenging the "More Is Better" Assumption

    Science.gov (United States)

    Lam, Chak Fu; DeRue, D. Scott; Karam, Elizabeth P.; Hollenbeck, John R.

    2011-01-01

    Previous research on feedback frequency suggests that more frequent feedback improves learning and task performance (Salmoni, Schmidt, & Walter, 1984). Drawing from resource allocation theory (Kanfer & Ackerman, 1989), we challenge the "more is better" assumption and propose that frequent feedback can overwhelm an individual's cognitive resource…

  6. Interação de variáveis biomecânicas na composição de "feedback" visual aumentado para o ensino do ciclismo Interacción de variables biomecánicas en la composición de feedback visual aumentado para el enseñanza del ciclismo Interaction of biomechanical variables in the composition of visual augmented feedback for learning cycling

    OpenAIRE

    Guilherme Garcia Holderbaum; Ricardo Demétrio de Souza Petersen; Antônio Carlos Stringhini Guimarães

    2012-01-01

    O objetivo deste estudo foi testar uma metodologia para o ensino da técnica da pedalada do ciclismo utilizando variáveis biomecánicas para desenvolver um sistema de "feedback" visual aumentado (FVA). Participaram do estudo 19 indivíduos, sem experiência no ciclismo , divididos em grupo experimental (n = 10) e controle (n = 9). Inicialmente foi realizado um pré-teste para determinar o consumo máximo de oxigênio (VO2máx) bem como a carga de trabalho utilizada nas sessões práticas que correspond...

  7. Noise destroys feedback enhanced figure-ground segmentation but not feedforward figure-ground segmentation

    Science.gov (United States)

    Romeo, August; Arall, Marina; Supèr, Hans

    2012-01-01

    Figure-ground (FG) segmentation is the separation of visual information into background and foreground objects. In the visual cortex, FG responses are observed in the late stimulus response period, when neurons fire in tonic mode, and are accompanied by a switch in cortical state. When such a switch does not occur, FG segmentation fails. Currently, it is not known what happens in the brain on such occasions. A biologically plausible feedforward spiking neuron model was previously devised that performed FG segmentation successfully. After incorporating feedback the FG signal was enhanced, which was accompanied by a change in spiking regime. In a feedforward model neurons respond in a bursting mode whereas in the feedback model neurons fired in tonic mode. It is known that bursts can overcome noise, while tonic firing appears to be much more sensitive to noise. In the present study, we try to elucidate how the presence of noise can impair FG segmentation, and to what extent the feedforward and feedback pathways can overcome noise. We show that noise specifically destroys the feedback enhanced FG segmentation and leaves the feedforward FG segmentation largely intact. Our results predict that noise produces failure in FG perception. PMID:22934028

  8. Macular pigment and visual performance in glare: benefits for photostress recovery, disability glare, and visual discomfort.

    Science.gov (United States)

    Stringham, James M; Garcia, Paul V; Smith, Peter A; McLin, Leon N; Foutch, Brian K

    2011-09-22

    One theory of macular pigment's (MP) presence in the fovea is to improve visual performance in glare. This study sought to determine the effect of MP level on three aspects of visual performance in glare: photostress recovery, disability glare, and visual discomfort. Twenty-six subjects participated in the study. Spatial profiles of MP optical density were assessed with heterochromatic flicker photometry. Glare was delivered via high-bright-white LEDs. For the disability glare and photostress recovery portions of the experiment, the visual task consisted of correct identification of a 1° Gabor patch's orientation. Visual discomfort during the glare presentation was assessed with a visual discomfort rating scale. Pupil diameter was monitored with an infrared (IR) camera. MP level correlated significantly with all the outcome measures. Higher MP optical densities (MPODs) resulted in faster photostress recovery times (average P disability glare contrast thresholds (average P visual discomfort (P = 0.002). Smaller pupil diameter during glare presentation significantly correlated with higher visual discomfort ratings (P = 0.037). MP correlates with three aspects of visual performance in glare. Unlike previous studies of MP and glare, the present study used free-viewing conditions, in which effects of iris pigmentation and pupil size could be accounted for. The effects described, therefore, can be extended more confidently to real-world, practical visual performance benefits. Greater iris constriction resulted (paradoxically) in greater visual discomfort. This finding may be attributable to the neurobiologic mechanism that mediates the pain elicited by light.

  9. Stochastic two-delay differential model of delayed visual feedback effects on postural dynamics.

    Science.gov (United States)

    Boulet, Jason; Balasubramaniam, Ramesh; Daffertshofer, Andreas; Longtin, André

    2010-01-28

    We report on experiments and modelling involving the 'visuo-postural control loop' in the upright stance. We experimentally manipulated an artificial delay to the visual feedback during standing, presented at delays ranging from 0 to 1 s in increments of 250 ms. Using stochastic delay differential equations, we explicitly modelled the centre-of-pressure (COP) and centre-of-mass (COM) dynamics with two independent delay terms for vision and proprioception. A novel 'drifting fixed point' hypothesis was used to describe the fluctuations of the COM with the COP being modelled as a faster, corrective process of the COM. The model was in good agreement with the data in terms of probability density functions, power spectral densities, short- and long-term correlations (Hurst exponents) as well the critical time between the two ranges. This journal is © 2010 The Royal Society

  10. Adaptive Performance-Constrained in Situ Visualization of Atmospheic Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dorier, Matthieu; Sisneros, Roberto; Bautista Gomez, Leonard; Peterka, Tom; Orf, Leigh; Rahmani, Lokman; Antoniu, Gabriel; Bouge, Luc

    2016-09-12

    While many parallel visualization tools now provide in situ visualization capabilities, the trend has been to feed such tools with large amounts of unprocessed output data and let them render everything at the highest possible resolution. This leads to an increased run time of simulations that still have to complete within a fixed-length job allocation. In this paper, we tackle the challenge of enabling in situ visualization under performance constraints. Our approach shuffles data across processes according to its content and filters out part of it in order to feed a visualization pipeline with only a reorganized subset of the data produced by the simulation. Our framework leverages fast, generic evaluation procedures to score blocks of data, using information theory, statistics, and linear algebra. It monitors its own performance and adapts dynamically to achieve appropriate visual fidelity within predefined performance constraints. Experiments on the Blue Waters supercomputer with the CM1 simulation show that our approach enables a 5 speedup with respect to the initial visualization pipeline and is able to meet performance constraints.

  11. It is all me: the effect of viewpoint on visual-vestibular recalibration.

    Science.gov (United States)

    Schomaker, Judith; Tesch, Joachim; Bülthoff, Heinrich H; Bresciani, Jean-Pierre

    2011-09-01

    Participants performed a visual-vestibular motor recalibration task in virtual reality. The task consisted of keeping the extended arm and hand stable in space during a whole-body rotation induced by a robotic wheelchair. Performance was first quantified in a pre-test in which no visual feedback was available during the rotation. During the subsequent adaptation phase, optical flow resulting from body rotation was provided. This visual feedback was manipulated to create the illusion of a smaller rotational movement than actually occurred, hereby altering the visual-vestibular mapping. The effects of the adaptation phase on hand stabilization performance were measured during a post-test that was identical to the pre-test. Three different groups of subjects were exposed to different perspectives on the visual scene, i.e., first-person, top view, or mirror view. Sensorimotor adaptation occurred for all three viewpoint conditions, performance in the post-test session showing a marked under-compensation relative to the pre-test performance. In other words, all viewpoints gave rise to a remapping between vestibular input and the motor output required to stabilize the arm. Furthermore, the first-person and mirror view adaptation induced a significant decrease in variability of the stabilization performance. Such variability reduction was not observed for the top view adaptation. These results suggest that even if all three viewpoints can evoke substantial adaptation aftereffects, the more naturalistic first-person view and the richer mirror view should be preferred when reducing motor variability constitutes an important issue.

  12. Finding the best visualization of an ontology

    DEFF Research Database (Denmark)

    Fabritius, Christina; Madsen, Nadia; Clausen, Jens

    2006-01-01

    An ontology is a classification model for a given domain.In information retrieval ontologies are used to perform broad searches.An ontology can be visualized as nodes and edges. Each node represents an element and each edge a relation between a parent and a child element. Working with an ontology....... One method uses a discrete location model to create an initial solution and we propose heuristic methods to further improve the visual result. We evaluate the visual results according to our success criteria and the feedback from users. Running times of the heuristic indicate that an improved version...

  13. Finding the best visualization of an ontology

    DEFF Research Database (Denmark)

    Fabritius, Christina Valentin; Madsen, Nadia Lyngaa; Clausen, Jens

    2004-01-01

    An ontology is a classification model for a given domain. In information retrieval ontologies are used to perform broad searches. An ontology can be visualized as nodes and edges. Each node represents an element and each edge a relation between a parent and a child element. Working with an ontology....... One method uses a discrete location model to create an initial solution and we propose heuristic methods to further improve the visual result. We evaluate the visual results according to our success criteria and the feedback from users. Running times of the heuristic indicate that an improved version...

  14. Visualization and Data Analysis for High-Performance Computing

    Energy Technology Data Exchange (ETDEWEB)

    Sewell, Christopher Meyer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-27

    This is a set of slides from a guest lecture for a class at the University of Texas, El Paso on visualization and data analysis for high-performance computing. The topics covered are the following: trends in high-performance computing; scientific visualization, such as OpenGL, ray tracing and volume rendering, VTK, and ParaView; data science at scale, such as in-situ visualization, image databases, distributed memory parallelism, shared memory parallelism, VTK-m, "big data", and then an analysis example.

  15. Pantomime-grasping: Advance knowledge of haptic feedback availability supports an absolute visuo-haptic calibration

    Directory of Open Access Journals (Sweden)

    Shirin eDavarpanah Jazi

    2016-05-01

    Full Text Available An emerging issue in movement neurosciences is whether haptic feedback influences the nature of the information supporting a simulated grasping response (i.e., pantomime-grasping. In particular, recent work by our group contrasted pantomime-grasping responses performed with (i.e., PH+ trials and without (i.e., PH- trials terminal haptic feedback in separate blocks of trials. Results showed that PH- trials were mediated via relative visual information. In contrast, PH+ trials showed evidence of an absolute visuo-haptic calibration – a finding attributed to an error signal derived from a comparison between expected and actual haptic feedback (i.e., an internal forward model. The present study examined whether advanced knowledge of haptic feedback availability influences the aforementioned calibration process. To that end, PH- and PH+ trials were completed in separate blocks (i.e., the feedback schedule used in our group’s previous study and a block wherein PH- and PH+ trials were randomly interleaved on a trial-by-trial basis (i.e., random feedback schedule. In other words, the random feedback schedule precluded participants from predicting whether haptic feedback would be available at the movement goal location. We computed just-noticeable-difference (JND values to determine whether responses adhered to, or violated, the relative psychophysical principles of Weber’s law. Results for the blocked feedback schedule replicated our group’s previous work, whereas in the random feedback schedule PH- and PH+ trials were supported via relative visual information. Accordingly, we propose that a priori knowledge of haptic feedback is necessary to support an absolute visuo-haptic calibration. Moreover, our results demonstrate that the presence and expectancy of haptic feedback is an important consideration in contrasting the behavioral and neural properties of natural and stimulated (i.e., pantomime-grasping grasping.

  16. The effect of organizational learning from performance feedback on team attention focus

    NARCIS (Netherlands)

    Lucas, G.J.M.; Zijlmans, Marius; Meeus, M.T.H.; Blettner, D.P.; Sund, K.J.; Galavan, R.J.; Huff, A.S.

    2016-01-01

    In this chapter, we present a theory on how organizational performance feedback influences individual decision-maker cognitions and thereby changes a team’s attention focus in terms of strategy. We argue that when performance compares unfavorably to aspiration levels, decision-makers reconsider

  17. Clinical skills-related learning goals of senior medical students after performance feedback.

    Science.gov (United States)

    Chang, Anna; Chou, Calvin L; Teherani, Arianne; Hauer, Karen E

    2011-09-01

    Lifelong learning is essential for doctors to maintain competence in clinical skills. With performance feedback, learners should be able to formulate specific and achievable learning goals in areas of need. We aimed to determine: (i) the type and specificity of medical student learning goals after a required clinical performance examination; (ii) differences in goal setting among low, average and high performers, and (iii) whether low performers articulate learning goals that are concordant with their learning needs. We conducted a single-site, multi-year, descriptive comparison study. Senior medical students were given performance benchmarks, individual feedback and guidelines on learning goals; each student was subsequently instructed to write two clinical skills learning goals. Investigators coded the learning goals for specificity, categorised the goals, and performed statistical analyses to determine their concordance with student performance level (low, average or high) in data gathering (history taking and physical examination) or communication skills. All 208 students each wrote two learning goals and most (n=200, 96%) wrote two specific learning goals. Nearly two-thirds of low performers in data gathering wrote at least one learning goal that referred to history taking or physical examination; one-third wrote learning goals pertaining to the organisation of the encounter. High performers in data gathering wrote significantly more patient education goals and significantly fewer history-taking goals than average or low performers. Only 50% of low performers in communication wrote learning goals related to communication skills. Low performers in communication were significantly more likely than average or high performers to identify learning goals related to improving performance in future examinations. The provision of performance benchmarking, individual feedback and brief written guidelines helped most senior medical students in our study to write specific

  18. Delayed action does not always require the ventral stream: a study on a patient with visual form agnosia.

    Science.gov (United States)

    Hesse, Constanze; Schenk, Thomas

    2014-05-01

    It has been suggested that while movements directed at visible targets are processed within the dorsal stream, movements executed after delay rely on the visual representations of the ventral stream (Milner & Goodale, 2006). This interpretation is supported by the observation that a patient with ventral stream damage (D.F.) has trouble performing accurate movements after a delay, but performs normally when the target is visible during movement programming. We tested D.F.'s visuomotor performance in a letter-posting task whilst varying the amount of visual feedback available. Additionally, we also varied whether D.F. received tactile feedback at the end of each trial (posting through a letter box vs posting on a screen) and whether environmental cues were available during the delay period (removing the target only vs suppressing vision completely with shutter glasses). We found that in the absence of environmental cues patient D.F. was unaffected by the introduction of delay and performed as accurately as healthy controls. However, when environmental cues and vision of the moving hand were available during and after the delay period, D.F.'s visuomotor performance was impaired. Thus, while healthy controls benefit from the availability of environmental landmarks and/or visual feedback of the moving hand, such cues seem less beneficial to D.F. Taken together our findings suggest that ventral stream damage does not always impact the ability to make delayed movements but compromises the ability to use environmental landmarks and visual feedback efficiently. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Influence of Vibrotactile Feedback on Controlling Tilt Motion After Spaceflight

    Science.gov (United States)

    Wood, S. J.; Rupert, A. H.; Vanya, R. D.; Esteves, J. T.; Clement, G.

    2011-01-01

    We hypothesize that adaptive changes in how inertial cues from the vestibular system are integrated with other sensory information leads to perceptual disturbances and impaired manual control following transitions between gravity environments. The primary goals of this ongoing post-flight investigation are to quantify decrements in manual control of tilt motion following short-duration spaceflight and to evaluate vibrotactile feedback of tilt as a sensorimotor countermeasure. METHODS. Data is currently being collected on 9 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s, body axis, thereby eliciting canal reflexes without concordant otolith or visual cues. A simple 4 tactor system was implemented to provide feedback when tilt position exceeded predetermined levels in either device. Closed-loop nulling tasks are performed during random tilt steps or sum-of-sines (TTS only) with and without vibrotactile feedback of chair position. RESULTS. On landing day the manual control performance without vibrotactile feedback was reduced by >30% based on the gain or the amount of tilt disturbance successfully nulled. Manual control performance tended to return to baseline levels within 1-2 days following landing. Root-mean-square position error and tilt velocity were significantly reduced with vibrotactile feedback. CONCLUSIONS. These preliminary results are consistent with our hypothesis that adaptive changes in vestibular processing corresponds to reduced manual control performance following G-transitions. A simple vibrotactile prosthesis improves the ability to null out tilt motion within a limited range of motion disturbances.

  20. Praise in Public, Criticize in Private? An Assessment of Performance Feedback Transparency in a Classroom Setting

    Science.gov (United States)

    Seevers, Matthew T.; Rowe, William J.; Skinner, Steven J.

    2014-01-01

    Conventional wisdom in sales management encourages public delivery of positive feedback, and private delivery of negative feedback. In stark contrast, U.S. educators typically provide all performance feedback in relative (if not strict) privacy to comply with the Family Educational Rights and Privacy Act (FERPA). To investigate this discrepancy,…

  1. The positive effect of mirror visual feedback on arm control in children with Spastic hemiparetic cerebral palsy is dependent on which arm is viewed

    NARCIS (Netherlands)

    Smorenburg, A; Ledebt, A.; Feltham, M.; Deconinck, F.; Savelsbergh, G.J.P.

    2011-01-01

    Mirror visual feedback has previously been found to reduce disproportionate interlimb variability and neuromuscular activity in the arm muscles in children with Spastic Hemiparetic Cerebral Palsy (SHCP). The aim of the current study was to determine whether these positive effects are generated by

  2. An Investigation of Response Generalization across Cleaning and Restocking Behaviors in the Context of Performance Feedback

    Science.gov (United States)

    DeRiso, Anthony; Ludwig, Timothy D.

    2012-01-01

    The impact of task clarification and performance feedback on cleaning and restocking behaviors on both targeted and nontargeted behaviors was analyzed using an AB multiple baseline design across behaviors. Task clarification was presented on an enlarged poster to the serving staff at a fine dining restaurant. Group performance feedback was…

  3. Virtual Reality Feedback Cues for Improvement of Gait in Patients with Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Samih Badarny

    2014-03-01

    Full Text Available Background: Our aim was to study the effects of visual feedback cues, responding dynamically to patient's self‐motion and provided through a portable see‐through virtual reality apparatus, on the walking abilities of patients with Parkinson's disease.Methods: Twenty patients participated. On‐line and residual effects on walking speed and stride length were measured. Results Attaching the visual feedback device to the patient with the display turned off showed a negligible effect of about 2%. With the display turned on, 56% of the patients improved either their walking speed, or their stride length, or both, by over 20%. After device removal, and waiting for 15 minutes, the patients were instructed to walk again: 68% of the patients showed over 20% improvement in either walking speed or stride length or both. One week after participating in the first test, 36% of the patients showed over 20% improvement in baseline performance with respect to the previous test. Some of the patients reported that they still walked on the tiles in their minds.Discussion: Improvements in walking abilities were measured in patients with Parkinson's disease using virtual reality visual feedback cues. Residual effects suggest the examination of this approach in a comprehensive therapy program.

  4. Corticocortical feedback increases the spatial extent of normalization.

    Science.gov (United States)

    Nassi, Jonathan J; Gómez-Laberge, Camille; Kreiman, Gabriel; Born, Richard T

    2014-01-01

    Normalization has been proposed as a canonical computation operating across different brain regions, sensory modalities, and species. It provides a good phenomenological description of non-linear response properties in primary visual cortex (V1), including the contrast response function and surround suppression. Despite its widespread application throughout the visual system, the underlying neural mechanisms remain largely unknown. We recently observed that corticocortical feedback contributes to surround suppression in V1, raising the possibility that feedback acts through normalization. To test this idea, we characterized area summation and contrast response properties in V1 with and without feedback from V2 and V3 in alert macaques and applied a standard normalization model to the data. Area summation properties were well explained by a form of divisive normalization, which computes the ratio between a neuron's driving input and the spatially integrated activity of a "normalization pool." Feedback inactivation reduced surround suppression by shrinking the spatial extent of the normalization pool. This effect was independent of the gain modulation thought to mediate the influence of contrast on area summation, which remained intact during feedback inactivation. Contrast sensitivity within the receptive field center was also unaffected by feedback inactivation, providing further evidence that feedback participates in normalization independent of the circuit mechanisms involved in modulating contrast gain and saturation. These results suggest that corticocortical feedback contributes to surround suppression by increasing the visuotopic extent of normalization and, via this mechanism, feedback can play a critical role in contextual information processing.

  5. Motor Training: Comparison of Visual and Auditory Coded Proprioceptive Cues

    Directory of Open Access Journals (Sweden)

    Philip Jepson

    2012-05-01

    Full Text Available Self-perception of body posture and movement is achieved through multi-sensory integration, particularly the utilisation of vision, and proprioceptive information derived from muscles and joints. Disruption to these processes can occur following a neurological accident, such as stroke, leading to sensory and physical impairment. Rehabilitation can be helped through use of augmented visual and auditory biofeedback to stimulate neuro-plasticity, but the effective design and application of feedback, particularly in the auditory domain, is non-trivial. Simple auditory feedback was tested by comparing the stepping accuracy of normal subjects when given a visual spatial target (step length and an auditory temporal target (step duration. A baseline measurement of step length and duration was taken using optical motion capture. Subjects (n=20 took 20 ‘training’ steps (baseline ±25% using either an auditory target (950 Hz tone, bell-shaped gain envelope or visual target (spot marked on the floor and were then asked to replicate the target step (length or duration corresponding to training with all feedback removed. Visual cues (mean percentage error=11.5%; SD ± 7.0%; auditory cues (mean percentage error = 12.9%; SD ± 11.8%. Visual cues elicit a high degree of accuracy both in training and follow-up un-cued tasks; despite the novelty of the auditory cues present for subjects, the mean accuracy of subjects approached that for visual cues, and initial results suggest a limited amount of practice using auditory cues can improve performance.

  6. Evaluation of stiffness feedback for hard nodule identification on a phantom silicone model

    OpenAIRE

    Li, M.; Konstantinova, J.; Xu, G.; He, B.; Aminzadeh, V.; Xie, J.; Wurdemann, H.; Althoefer, K.

    2017-01-01

    Haptic information in robotic surgery can significantly improve clinical outcomes and help detect hard soft-tissue inclusions that indicate potential abnormalities. Visual representation of tissue stiffness information is a cost-effective technique. Meanwhile, direct force feedback, although considerably more expensive than visual representation, is an intuitive method of conveying information regarding tissue stiffness to surgeons. In this study, real-time visual stiffness feedback by slidin...

  7. Training based on mirror visual feedback influences transcallosal communication.

    Science.gov (United States)

    Avanzino, Laura; Raffo, Alessia; Pelosin, Elisa; Ogliastro, Carla; Marchese, Roberta; Ruggeri, Piero; Abbruzzese, Giovanni

    2014-08-01

    Mirror visual feedback (MVF) therapy has been demonstrated to be successful in neurorehabilitation, probably inducing neuroplasticity changes in the primary motor cortex (M1). However, it is not known whether MVF training influences the hemispheric balance between the M1s. This topic is of extreme relevance when MVF training is applied to stroke rehabilitation, as the competitive interaction between the two hemispheres induces abnormal interhemispheric inhibition (IHI) that weakens motor function in stroke patients. In the present study, we evaluated, in a group of healthy subjects, the effect of motor training and MVF training on the excitability of the two M1s and the IHI between M1s. The IHI from the 'active' M1 to the opposite M1 (where 'active' means the M1 contralateral to the moving hand in the motor training and the M1 of the seen hand in the MVF training) increased, after training, in both the experimental conditions. Only after motor training did we observe an increase in the excitability of the active M1. Our findings show that training based on MVF may influence the excitability of the transcallosal pathway and support its use in disorders where abnormal IHI is a potential target, such as stroke, where an imbalance between the affected and unaffected M1s has been documented. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Feedback and Incentives:

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie-Claire

    This paper experimentally investigates the impact of different pay and relative performance information policies on employee effort. We explore three information policies: No feedback about relative performance, feedback given halfway through the production period, and continuously updated feedba...... of positive peer effects since the underdogs almost never quit the competition even when lagging significantly behind, and frontrunners do not slack off. Moreover, in both pay schemes information feedback reduces the quality of the low performers' work....

  9. Instructor feedback versus no instructor feedback on performance in a laparoscopic virtual reality simulator

    DEFF Research Database (Denmark)

    Strandbygaard, Jeanett; Bjerrum, Flemming; Maagaard, Mathilde

    2013-01-01

    % vs 49%; P = 0.004). Men used less time (in minutes) than women (P = 0.037), but no sex difference was observed for repetitions (P = 0.20). Participants in the intervention group had higher self-perception regarding surgical skills after the trial (P = 0.011). CONCLUSIONS:: Instructor feedback...... increases the efficiency when training a complex operational task on a virtual reality simulator; time and repetitions used to achieve a predefined proficiency level were significantly reduced in the group that received instructor feedback compared with the control group. Trial registration number: NCT......OBJECTIVE:: To investigate the impact of instructor feedback versus no instructor feedback when training a complex operational task on a laparoscopic virtual reality simulator. BACKGROUND:: Simulators are now widely accepted as a training tool, but there is insufficient knowledge about how much...

  10. Excessive sensitivity to uncertain visual input in L-dopa induced dyskinesias in Parkinson’s disease: further implications for cerebellar involvement

    Directory of Open Access Journals (Sweden)

    James eStevenson

    2014-02-01

    Full Text Available When faced with visual uncertainty during motor performance, humans rely more on predictive forward models and proprioception and attribute lesser importance to the ambiguous visual feedback. Though disrupted predictive control is typical of patients with cerebellar disease, sensorimotor deficits associated with the involuntary and often unconscious nature of L-dopa-induced dyskinesias in Parkinson’s disease (PD suggests dyskinetic subjects may also demonstrate impaired predictive motor control. Methods: We investigated the motor performance of 9 dyskinetic and 10 non-dyskinetic PD subjects on and off L-dopa, and of 10 age-matched control subjects, during a large-amplitude, overlearned, visually-guided tracking task. Ambiguous visual feedback was introduced by adding ‘jitter’ to a moving target that followed a Lissajous pattern. Root mean square (RMS tracking error was calculated, and ANOVA, robust multivariate linear regression and linear dynamical system analyses were used to determine the contribution of speed and ambiguity to tracking performance. Results: Increasing target ambiguity and speed contributed significantly more to the RMS error of dyskinetic subjects off medication. L-dopa improved the RMS tracking performance of both PD groups. At higher speeds, controls and PDs without dyskinesia were able to effectively de-weight ambiguous visual information. Conclusions: PDs’ visually-guided motor performance degrades with visual jitter and speed of movement to a greater degree compared to age-matched controls. However, there are fundamental differences in PDs with and without dyskinesia: subjects without dyskinesia are generally slow, and less responsive to dynamic changes in motor task requirements but, PDs with dyskinesia there was a trade-off between overall performance and inappropriate reliance on ambiguous visual feedback. This is likely associated with functional changes in posterior parietal-ponto-cerebellar pathways.

  11. The effect of metacognitive monitoring feedback on performance in a computer-based training simulation.

    Science.gov (United States)

    Kim, Jung Hyup

    2018-02-01

    This laboratory experiment was designed to study the effect of metacognitive monitoring feedback on performance in a computer-based training simulation. According to prior research on metacognition, the accurate checking of learning is a critical part of improving the quality of human performance. However, only rarely have researchers studied the learning effects of the accurate checking of retrospective confidence judgments (RCJs) during a computer-based military training simulation. In this study, we provided participants feedback screens after they had completed a warning task and identification task in a radar monitoring simulation. There were two groups in this experiment. One group (group A) viewed the feedback screens with the flight path of all target aircraft and the triangular graphs of both RCJ scores and human performance together. The other group (group B) only watched the feedback screens with the flight path of all target aircraft. There was no significant difference in performance improvement between groups A and B for the warning task (Day 1: group A - 0.347, group B - 0.305; Day 2: group A - 0.488, group B - 0.413). However, the identification task yielded a significant difference in performance improvement between these groups (Day 1: group A - 0.174, group B - 0.1555; Day 2: group A - 0.324, group B - 0.199). The results show that debiasing self-judgment of the identification task produces a positive training effect on learners. The findings of this study will be beneficial for designing an advanced instructional strategy in a simulation-based training environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Visual-perceptual mismatch in robotic surgery.

    Science.gov (United States)

    Abiri, Ahmad; Tao, Anna; LaRocca, Meg; Guan, Xingmin; Askari, Syed J; Bisley, James W; Dutson, Erik P; Grundfest, Warren S

    2017-08-01

    The principal objective of the experiment was to analyze the effects of the clutch operation of robotic surgical systems on the performance of the operator. The relative coordinate system introduced by the clutch operation can introduce a visual-perceptual mismatch which can potentially have negative impact on a surgeon's performance. We also assess the impact of the introduction of additional tactile sensory information on reducing the impact of visual-perceptual mismatch on the performance of the operator. We asked 45 novice subjects to complete peg transfers using the da Vinci IS 1200 system with grasper-mounted, normal force sensors. The task involves picking up a peg with one of the robotic arms, passing it to the other arm, and then placing it on the opposite side of the view. Subjects were divided into three groups: aligned group (no mismatch), the misaligned group (10 cm z axis mismatch), and the haptics-misaligned group (haptic feedback and z axis mismatch). Each subject performed the task five times, during which the grip force, time of completion, and number of faults were recorded. Compared to the subjects that performed the tasks using a properly aligned controller/arm configuration, subjects with a single-axis misalignment showed significantly more peg drops (p = 0.011) and longer time to completion (p sensors showed no difference between the different groups. The visual-perceptual mismatch created by the misalignment of the robotic controls relative to the robotic arms has a negative impact on the operator of a robotic surgical system. Introduction of other sensory information and haptic feedback systems can help in potentially reducing this effect.

  13. Neural activation during imitation with or without performance feedback: An fMRI study.

    Science.gov (United States)

    Zhang, Kaihua; Wang, Hui; Dong, Guangheng; Wang, Mengxing; Zhang, Jilei; Zhang, Hui; Meng, Weixia; Du, Xiaoxia

    2016-08-26

    In our daily lives, we often receive performance feedback (PF) during imitative learning, and we adjust our behaviors accordingly to improve performance. However, little is known regarding the neural mechanisms underlying this learning process. We hypothesized that appropriate PF would enhance neural activation or recruit additional brain areas during subsequent action imitation. Pictures of 20 different finger gestures without any social meaning were shown to participants from the first-person perspective. Imitation with or without PF was investigated by functional magnetic resonance imaging in 30 healthy subjects. The PF was given by a real person or by a computer. PF from a real person induced hyperactivation of the parietal lobe (precuneus and cuneus), cingulate cortex (posterior and anterior), temporal lobe (superior and transverse temporal gyri), and cerebellum (posterior and anterior lobes) during subsequent imitation. The positive PF and negative PF from a real person, induced the activation of more brain areas during the following imitation. The hyperactivation of the cerebellum, posterior cingulate cortex, precuneus, and cuneus suggests that the subjects exhibited enhanced motor control and visual attention during imitation after PF. Additionally, random PF from a computer had a small effect on the next imitation. We suggest that positive and accurate PF may be helpful for imitation learning. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Corticocortical feedback increases the spatial extent of normalization

    Science.gov (United States)

    Nassi, Jonathan J.; Gómez-Laberge, Camille; Kreiman, Gabriel; Born, Richard T.

    2014-01-01

    Normalization has been proposed as a canonical computation operating across different brain regions, sensory modalities, and species. It provides a good phenomenological description of non-linear response properties in primary visual cortex (V1), including the contrast response function and surround suppression. Despite its widespread application throughout the visual system, the underlying neural mechanisms remain largely unknown. We recently observed that corticocortical feedback contributes to surround suppression in V1, raising the possibility that feedback acts through normalization. To test this idea, we characterized area summation and contrast response properties in V1 with and without feedback from V2 and V3 in alert macaques and applied a standard normalization model to the data. Area summation properties were well explained by a form of divisive normalization, which computes the ratio between a neuron's driving input and the spatially integrated activity of a “normalization pool.” Feedback inactivation reduced surround suppression by shrinking the spatial extent of the normalization pool. This effect was independent of the gain modulation thought to mediate the influence of contrast on area summation, which remained intact during feedback inactivation. Contrast sensitivity within the receptive field center was also unaffected by feedback inactivation, providing further evidence that feedback participates in normalization independent of the circuit mechanisms involved in modulating contrast gain and saturation. These results suggest that corticocortical feedback contributes to surround suppression by increasing the visuotopic extent of normalization and, via this mechanism, feedback can play a critical role in contextual information processing. PMID:24910596

  15. Self-Management of Patient Body Position, Pose, and Motion Using Wide-Field, Real-Time Optical Measurement Feedback: Results of a Volunteer Study

    International Nuclear Information System (INIS)

    Parkhurst, James M.; Price, Gareth J.; Sharrock, Phil J.; Jackson, Andrew S.N.; Stratford, Julie; Moore, Christopher J.

    2013-01-01

    Purpose: We present the results of a clinical feasibility study, performed in 10 healthy volunteers undergoing a simulated treatment over 3 sessions, to investigate the use of a wide-field visual feedback technique intended to help patients control their pose while reducing motion during radiation therapy treatment. Methods and Materials: An optical surface sensor is used to capture wide-area measurements of a subject's body surface with visualizations of these data displayed back to them in real time. In this study we hypothesize that this active feedback mechanism will enable patients to control their motion and help them maintain their setup pose and position. A capability hierarchy of 3 different level-of-detail abstractions of the measured surface data is systematically compared. Results: Use of the device enabled volunteers to increase their conformance to a reference surface, as measured by decreased variability across their body surfaces. The use of visual feedback also enabled volunteers to reduce their respiratory motion amplitude to 1.7 ± 0.6 mm compared with 2.7 ± 1.4 mm without visual feedback. Conclusions: The use of live feedback of their optically measured body surfaces enabled a set of volunteers to better manage their pose and motion when compared with free breathing. The method is suitable to be taken forward to patient studies

  16. On optimal feedforward and ILC : the role of feedback for optimal performance and inferential control

    NARCIS (Netherlands)

    van Zundert, J.C.D.; Oomen, T.A.E

    2017-01-01

    The combination of feedback control with inverse model feedforward control or iterative learning control is known to yield high performance. The aim of this paper is to clarify the role of feedback in the design of feedforward controllers, with specific attention to the inferential situation. Recent

  17. 'Robot' Hand Illusion under Delayed Visual Feedback: Relationship between the Senses of Ownership and Agency.

    Directory of Open Access Journals (Sweden)

    Mohamad Arif Fahmi Ismail

    Full Text Available The rubber hand illusion (RHI is an illusion of the self-ownership of a rubber hand that is touched synchronously with one's own hand. While the RHI relates to visual and tactile integration, we can also consider a similar illusion with visual and motor integration on a fake hand. We call this a "robot hand illusion" (RoHI, which relates to both the senses of ownership and agency. Here we investigate the effect of delayed visual feedback on the RoHI. Participants viewed a virtual computer graphic hand controlled by their hand movement recorded using a data glove device. We inserted delays of various lengths between the participant's hand and the virtual hand movements (90-590 ms, and the RoHI effects for each delay condition were systematically tested using a questionnaire. The results showed that the participants felt significantly greater RoHI effects with temporal discrepancies of less than 190 ms compared with longer temporal discrepancies, both in the senses of ownership and agency. Additionally, participants felt significant, but weaker, RoHI effects with temporal discrepancies of 290-490 ms in the sense of agency, but not in the sense of ownership. The participants did not feel a RoHI with temporal discrepancies of 590 ms in either the senses of agency or ownership. Our results suggest that a time window of less than 200 ms is critical for multi-sensory integration processes constituting self-body image.

  18. 'Robot' Hand Illusion under Delayed Visual Feedback: Relationship between the Senses of Ownership and Agency.

    Science.gov (United States)

    Ismail, Mohamad Arif Fahmi; Shimada, Sotaro

    2016-01-01

    The rubber hand illusion (RHI) is an illusion of the self-ownership of a rubber hand that is touched synchronously with one's own hand. While the RHI relates to visual and tactile integration, we can also consider a similar illusion with visual and motor integration on a fake hand. We call this a "robot hand illusion" (RoHI), which relates to both the senses of ownership and agency. Here we investigate the effect of delayed visual feedback on the RoHI. Participants viewed a virtual computer graphic hand controlled by their hand movement recorded using a data glove device. We inserted delays of various lengths between the participant's hand and the virtual hand movements (90-590 ms), and the RoHI effects for each delay condition were systematically tested using a questionnaire. The results showed that the participants felt significantly greater RoHI effects with temporal discrepancies of less than 190 ms compared with longer temporal discrepancies, both in the senses of ownership and agency. Additionally, participants felt significant, but weaker, RoHI effects with temporal discrepancies of 290-490 ms in the sense of agency, but not in the sense of ownership. The participants did not feel a RoHI with temporal discrepancies of 590 ms in either the senses of agency or ownership. Our results suggest that a time window of less than 200 ms is critical for multi-sensory integration processes constituting self-body image.

  19. Interpreting Feedback: A Discourse Analysis of Teacher Feedback and Student Identity

    Science.gov (United States)

    Torres, J. T.; Anguiano, Carlos J.

    2016-01-01

    Feedback has typically been studied as a means of improving academic performance. Few studies inquire into the processes by which feedback shapes student identity. The authors carry out a discourse analysis of written comments to explore how feedback is discursively constructed by both teachers and students. Analysis of written feedback,…

  20. Visualization and analysis of flow structures in an open cavity

    Science.gov (United States)

    Liu, Jun; Cai, Jinsheng; Yang, Dangguo; Wu, Junqiang; Wang, Xiansheng

    2018-05-01

    A numerical study is performed on the supersonic flow over an open cavity at Mach number of 1.5. A newly developed visualization method is employed to visualize the complicated flow structures, which provide an insight into major flow physics. Four types of shock/compressive waves which existed in experimental schlieren are observed in numerical visualization results. Furthermore, other flow structures such as multi-scale vortices are also obtained in the numerical results. And a new type of shocklet which is beneath large vortices is found. The shocklet beneath the vortex originates from leading edge, then, is strengthened by successive interactions between feedback compressive waves and its attached vortex. Finally, it collides against the trailing surface and generates a large number of feedback compressive waves and intensive pressure fluctuations. It is suggested that the shocklets beneath vortex play an important role of cavity self-sustained oscillation.

  1. Control of aperture closure initiation during reach-to-grasp movements under manipulations of visual feedback and trunk involvement in Parkinson's disease.

    Science.gov (United States)

    Rand, Miya Kato; Lemay, Martin; Squire, Linda M; Shimansky, Yury P; Stelmach, George E

    2010-03-01

    The present project was aimed at investigating how two distinct and important difficulties (coordination difficulty and pronounced dependency on visual feedback) in Parkinson's disease (PD) affect each other for the coordination between hand transport toward an object and the initiation of finger closure during reach-to-grasp movement. Subjects with PD and age-matched healthy subjects made reach-to-grasp movements to a dowel under conditions in which the target object and/or the hand were either visible or not visible. The involvement of the trunk in task performance was manipulated by positioning the target object within or beyond the participant's outstretched arm to evaluate the effects of increasing the complexity of intersegmental coordination under different conditions related to the availability of visual feedback in subjects with PD. General kinematic characteristics of the reach-to-grasp movements of the subjects with PD were altered substantially by the removal of target object visibility. Compared with the controls, the subjects with PD considerably lengthened transport time, especially during the aperture closure period, and decreased peak velocity of wrist and trunk movement without target object visibility. Most of these differences were accentuated when the trunk was involved. In contrast, these kinematic parameters did not change depending on the visibility of the hand for both groups. The transport-aperture coordination was assessed in terms of the control law according to which the initiation of aperture closure during the reach occurred when the hand distance-to-target crossed a hand-target distance threshold for grasp initiation that is a function of peak aperture, hand velocity and acceleration, trunk velocity and acceleration, and trunk-target distance at the time of aperture closure initiation. When the hand or the target object was not visible, both groups increased the hand-target distance threshold for grasp initiation compared to its

  2. Improvements in Cycling Time Trial Performance Are Not Sustained Following the Acute Provision of Challenging and Deceptive Feedback

    Directory of Open Access Journals (Sweden)

    Hollie S Jones

    2016-09-01

    Full Text Available TThe provision of performance-related feedback during exercise is acknowledged as an influential external cue used to inform pacing decisions. The provision of this feedback in a challenging or deceptive context allows research to explore how feedback can be used to improve performance and influence perceptual responses. However, the effects of deception on both acute and residual responses have yet to be explored, despite potential application for performance enhancement. Therefore, this study investigated the effects of challenging and deceptive feedback on perceptual responses and performance in self-paced cycling time trials (TT and explored whether changes in performance are sustained in a subsequent TT following the disclosure of the deception.Seventeen trained male cyclists were assigned to either an accurate or deceptive feedback group and performed four 16.1 km cycling TTs; 1 and 2 ride-alone baseline TTs where a fastest baseline (FBL performance was identified, 3 a TT against a virtual avatar representing 102% of their FBL performance (PACER, and 4 a subsequent ride-alone TT (SUB. The deception group, however, were initially informed that the avatar accurately represented their FBL, but prior to SUB were correctly informed of the nature of the avatar. Affect, self-efficacy and RPE were measured every quartile. Both groups performed PACER faster than FBL and SUB (p < 0.05 and experienced lower affect (p = 0.016, lower self-efficacy (p = 0.011, and higher RPE (p < 0.001 in PACER than FBL. No significant differences were found between FBL and SUB for any variable. The presence of the pacer rather than the manipulation of performance beliefs acutely facilitates TT performance and perceptual responses. Revealing that athletes’ performance beliefs were falsely negative due to deceptive feedback provision has no effect on subsequent perceptions or performance. A single experiential exposure may not be sufficient to produce meaningful

  3. Visual Search Performance in Patients with Vision Impairment: A Systematic Review.

    Science.gov (United States)

    Senger, Cassia; Margarido, Maria Rita Rodrigues Alves; De Moraes, Carlos Gustavo; De Fendi, Ligia Issa; Messias, André; Paula, Jayter Silva

    2017-11-01

    Patients with visual impairment are constantly facing challenges to achieve an independent and productive life, which depends upon both a good visual discrimination and search capacities. Given that visual search is a critical skill for several daily tasks and could be used as an index of the overall visual function, we investigated the relationship between vision impairment and visual search performance. A comprehensive search was undertaken using electronic PubMed, EMBASE, LILACS, and Cochrane databases from January 1980 to December 2016, applying the following terms: "visual search", "visual search performance", "visual impairment", "visual exploration", "visual field", "hemianopia", "search time", "vision lost", "visual loss", and "low vision". Two hundred seventy six studies from 12,059 electronic database files were selected, and 40 of them were included in this review. Studies included participants of all ages, both sexes, and the sample sizes ranged from 5 to 199 participants. Visual impairment was associated with worse visual search performance in several ophthalmologic conditions, which were either artificially induced, or related to specific eye and neurological diseases. This systematic review details all the described circumstances interfering with visual search tasks, highlights the need for developing technical standards, and outlines patterns for diagnosis and therapy using visual search capabilities.

  4. VISUAL ART TEACHERS AND PERFORMANCE ASSESSMENT ...

    African Journals Online (AJOL)

    Charles

    Senior Secondary school visual art teachers constituted the sample of this ... and Performance Assessment Methods in Nigerian Senior Secondary Schools – Bello .... definition includes knowledge, skills, attitudes, metacognition and strategic ...

  5. A Randomized Control Trial of Cardiopulmonary Feedback Devices and Their Impact on Infant Chest Compression Quality: A Simulation Study.

    Science.gov (United States)

    Austin, Andrea L; Spalding, Carmen N; Landa, Katrina N; Myer, Brian R; Donald, Cure; Smith, Jason E; Platt, Gerald; King, Heather C

    2017-10-27

    In effort to improve chest compression quality among health care providers, numerous feedback devices have been developed. Few studies, however, have focused on the use of cardiopulmonary resuscitation feedback devices for infants and children. This study evaluated the quality of chest compressions with standard team-leader coaching, a metronome (MetroTimer by ONYX Apps), and visual feedback (SkillGuide Cardiopulmonary Feedback Device) during simulated infant cardiopulmonary resuscitation. Seventy voluntary health care providers who had recently completed Pediatric Advanced Life Support or Basic Life Support courses were randomized to perform simulated infant cardiopulmonary resuscitation into 1 of 3 groups: team-leader coaching alone (control), coaching plus metronome, or coaching plus SkillGuide for 2 minutes continuously. Rate, depth, and frequency of complete recoil during cardiopulmonary resuscitation were recorded by the Laerdal SimPad device for each participant. American Heart Association-approved compression techniques were randomized to either 2-finger or encircling thumbs. The metronome was associated with more ideal compression rate than visual feedback or coaching alone (104/min vs 112/min and 113/min; P = 0.003, 0.019). Visual feedback was associated with more ideal depth than auditory (41 mm vs 38.9; P = 0.03). There were no significant differences in complete recoil between groups. Secondary outcomes of compression technique revealed a difference of 1 mm. Subgroup analysis of male versus female showed no difference in mean number of compressions (221.76 vs 219.79; P = 0.72), mean compression depth (40.47 vs 39.25; P = 0.09), or rate of complete release (70.27% vs 64.96%; P = 0.54). In the adult literature, feedback devices often show an increase in quality of chest compressions. Although more studies are needed, this study did not demonstrate a clinically significant improvement in chest compressions with the addition of a metronome or visual

  6. [Effects of real-time audiovisual feedback on secondary-school students' performance of chest compressions].

    Science.gov (United States)

    Abelairas-Gómez, Cristian; Rodríguez-Núñez, Antonio; Vilas-Pintos, Elisardo; Prieto Saborit, José Antonio; Barcala-Furelos, Roberto

    2015-06-01

    To describe the quality of chest compressions performed by secondary-school students trained with a realtime audiovisual feedback system. The learners were 167 students aged 12 to 15 years who had no prior experience with cardiopulmonary resuscitation (CPR). They received an hour of instruction in CPR theory and practice and then took a 2-minute test, performing hands-only CPR on a child mannequin (Prestan Professional Child Manikin). Lights built into the mannequin gave learners feedback about how many compressions they had achieved and clicking sounds told them when compressions were deep enough. All the learners were able to maintain a steady enough rhythm of compressions and reached at least 80% of the targeted compression depth. Fewer correct compressions were done in the second minute than in the first (P=.016). Real-time audiovisual feedback helps schoolchildren aged 12 to 15 years to achieve quality chest compressions on a mannequin.

  7. An audiovisual feedback device for compression depth, rate and complete chest recoil can improve the CPR performance of lay persons during self-training on a manikin

    International Nuclear Information System (INIS)

    Krasteva, Vessela; Jekova, Irena; Didon, Jean-Philippe

    2011-01-01

    This study aims to contribute to the scarce data available about the abilities of untrained lay persons to perform hands-only cardio-pulmonary resuscitation (CPR) on a manikin and the improvement of their skills during training with an autonomous CPR feedback device. The study focuses on the following questions: (i) Is there a need for such a CPR training device? (ii) How adequate are the embedded visual feedback and audio guidance for training of lay persons who learn and correct themselves in real time without instructor guidance? (iii) What is the achieved effect of only 3 min of training? This is a prospective study in which 63 lay persons (volunteers) received a debriefing to basic life support and then performed two consecutive 3 min trials of hands-only CPR on a manikin. The pre-training skills of the lay persons were tested in trial 1. The training process with audio guidance and visual feedback from a cardio compression control device (CC-Device) was recorded in trial 2. After initial debriefing for correct chest compressions (CC) with rate 85–115 min −1 , depth 3.8–5.4 cm and complete recoil, in trial 1 the lay persons were able to perform CC without feedback at mean rate 95.9 ± 18.9 min −1 , mean depth 4.13 ± 1.5 cm, with low proportions of 'correct depth', 'correct rate' and 'correct recoil' at 33%, 43%, 87%, resulting in the scarce proportion of 14% for compressions, which simultaneously fulfill the three quality criteria ('correct all'). In trial 2, the training process by the CC-Device was established by the significant improvement of the CC skills until the 60th second of training, when 'correct depth', 'correct rate' and 'correct recoil' attained the plateau of the highest quality at 82%, 90%, 96%, respectively, resulting in 73% 'correct all' compressions within 3 min of training. The training was associated with reduced variance of the mean rate 102.4 ± 4

  8. Gaze strategies during visually-guided versus memory-guided grasping.

    Science.gov (United States)

    Prime, Steven L; Marotta, Jonathan J

    2013-03-01

    Vision plays a crucial role in guiding motor actions. But sometimes we cannot use vision and must rely on our memory to guide action-e.g. remembering where we placed our eyeglasses on the bedside table when reaching for them with the lights off. Recent studies show subjects look towards the index finger grasp position during visually-guided precision grasping. But, where do people look during memory-guided grasping? Here, we explored the gaze behaviour of subjects as they grasped a centrally placed symmetrical block under open- and closed-loop conditions. In Experiment 1, subjects performed grasps in either a visually-guided task or memory-guided task. The results show that during visually-guided grasping, gaze was first directed towards the index finger's grasp point on the block, suggesting gaze targets future grasp points during the planning of the grasp. Gaze during memory-guided grasping was aimed closer to the blocks' centre of mass from block presentation to the completion of the grasp. In Experiment 2, subjects performed an 'immediate grasping' task in which vision of the block was removed immediately at the onset of the reach. Similar to the visually-guided results from Experiment 1, gaze was primarily directed towards the index finger location. These results support the 2-stream theory of vision in that motor planning with visual feedback at the onset of the movement is driven primarily by real-time visuomotor computations of the dorsal stream, whereas grasping remembered objects without visual feedback is driven primarily by the perceptual memory representations mediated by the ventral stream.

  9. Seeing the Errors You Feel Enhances Locomotor Performance but Not Learning.

    Science.gov (United States)

    Roemmich, Ryan T; Long, Andrew W; Bastian, Amy J

    2016-10-24

    In human motor learning, it is thought that the more information we have about our errors, the faster we learn. Here, we show that additional error information can lead to improved motor performance without any concomitant improvement in learning. We studied split-belt treadmill walking that drives people to learn a new gait pattern using sensory prediction errors detected by proprioceptive feedback. When we also provided visual error feedback, participants acquired the new walking pattern far more rapidly and showed accelerated restoration of the normal walking pattern during washout. However, when the visual error feedback was removed during either learning or washout, errors reappeared with performance immediately returning to the level expected based on proprioceptive learning alone. These findings support a model with two mechanisms: a dual-rate adaptation process that learns invariantly from sensory prediction error detected by proprioception and a visual-feedback-dependent process that monitors learning and corrects residual errors but shows no learning itself. We show that our voluntary correction model accurately predicted behavior in multiple situations where visual feedback was used to change acquisition of new walking patterns while the underlying learning was unaffected. The computational and behavioral framework proposed here suggests that parallel learning and error correction systems allow us to rapidly satisfy task demands without necessarily committing to learning, as the relative permanence of learning may be inappropriate or inefficient when facing environments that are liable to change. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Sensor-Based Interactive Balance Training with Visual Joint Movement Feedback for Improving Postural Stability in Diabetics with Peripheral Neuropathy: A Randomized Controlled Trial.

    Science.gov (United States)

    Grewal, Gurtej Singh; Schwenk, Michael; Lee-Eng, Jacqueline; Parvaneh, Saman; Bharara, Manish; Menzies, Robert A; Talal, Talal K; Armstrong, David G; Najafi, Bijan

    2015-01-01

    Individuals with diabetic peripheral neuropathy (DPN) have deficits in sensory and motor skills leading to inadequate proprioceptive feedback, impaired postural balance and higher fall risk. This study investigated the effect of sensor-based interactive balance training on postural stability and daily physical activity in older adults with diabetes. Thirty-nine older adults with DPN were enrolled (age 63.7 ± 8.2 years, BMI 30.6 ± 6, 54% females) and randomized to either an intervention (IG) or a control (CG) group. The IG received sensor-based interactive exercise training tailored for people with diabetes (twice a week for 4 weeks). The exercises focused on shifting weight and crossing virtual obstacles. Body-worn sensors were implemented to acquire kinematic data and provide real-time joint visual feedback during the training. Outcome measurements included changes in center of mass (CoM) sway, ankle and hip joint sway measured during a balance test while the eyes were open and closed at baseline and after the intervention. Daily physical activities were also measured during a 48-hour period at baseline and at follow-up. Analysis of covariance was performed for the post-training outcome comparison. Compared with the CG, the patients in the IG showed a significantly reduced CoM sway (58.31%; p = 0.009), ankle sway (62.7%; p = 0.008) and hip joint sway (72.4%; p = 0.017) during the balance test with open eyes. The ankle sway was also significantly reduced in the IG group (58.8%; p = 0.037) during measurements while the eyes were closed. The number of steps walked showed a substantial but nonsignificant increase (+27.68%; p = 0.064) in the IG following training. The results of this randomized controlled trial demonstrate that people with DPN can significantly improve their postural balance with diabetes-specific, tailored, sensor-based exercise training. The results promote the use of wearable technology in exercise training; however, future studies comparing this

  11. Handwriting performance in the absence of visual control in writer's cramp patients: Initial observations

    Directory of Open Access Journals (Sweden)

    Losch Florian

    2006-04-01

    Full Text Available Abstract Background The present study was aimed at investigating the writing parameters of writer's cramp patients and control subjects during handwriting of a test sentence in the absence of visual control. Methods Eight right-handed patients with writer's cramp and eight healthy volunteers as age-matched control subjects participated in the study. The experimental task consisted in writing a test sentence repeatedly for fifty times on a pressure-sensitive digital board. The subject did not have visual control on his handwriting. The writing performance was stored on a PC and analyzed off-line. Results During handwriting all patients developed a typical dystonic limb posture and reported an increase in muscular tension along the experimental session. The patients were significantly slower than the controls, with lower mean vertical pressure of the pen tip on the paper and they could not reach the endmost letter of the sentence in the given time window. No other handwriting parameter differences were found between the two groups. Conclusion Our findings indicate that during writing in the absence of visual feedback writer's cramp patients are slower and could not reach the endmost letter of the test sentence, but their level of automatization is not impaired and writer's cramp handwriting parameters are similar to those of the controls except for even lower vertical pressure of the pen tip on the paper, which is probably due to a changed strategy in such experimental conditions.

  12. The visual attention network untangled

    NARCIS (Netherlands)

    Nieuwenhuis, S.; Donner, T.H.

    2011-01-01

    Goals are represented in prefrontal cortex and modulate sensory processing in visual cortex. A new study combines TMS, fMRI and EEG to understand how feedback improves retention of behaviorally relevant visual information.

  13. Auditory, visual and auditory-visual memory and sequencing performance in typically developing children.

    Science.gov (United States)

    Pillai, Roshni; Yathiraj, Asha

    2017-09-01

    The study evaluated whether there exists a difference/relation in the way four different memory skills (memory score, sequencing score, memory span, & sequencing span) are processed through the auditory modality, visual modality and combined modalities. Four memory skills were evaluated on 30 typically developing children aged 7 years and 8 years across three modality conditions (auditory, visual, & auditory-visual). Analogous auditory and visual stimuli were presented to evaluate the three modality conditions across the two age groups. The children obtained significantly higher memory scores through the auditory modality compared to the visual modality. Likewise, their memory scores were significantly higher through the auditory-visual modality condition than through the visual modality. However, no effect of modality was observed on the sequencing scores as well as for the memory and the sequencing span. A good agreement was seen between the different modality conditions that were studied (auditory, visual, & auditory-visual) for the different memory skills measures (memory scores, sequencing scores, memory span, & sequencing span). A relatively lower agreement was noted only between the auditory and visual modalities as well as between the visual and auditory-visual modality conditions for the memory scores, measured using Bland-Altman plots. The study highlights the efficacy of using analogous stimuli to assess the auditory, visual as well as combined modalities. The study supports the view that the performance of children on different memory skills was better through the auditory modality compared to the visual modality. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Training effectiveness feedback

    International Nuclear Information System (INIS)

    Wiggin, N.A.

    1987-01-01

    A formal method of getting feedback about the job performance of employees is a necessary part of all the authors training programs. The formal process may prove to be inadequate if it is the only process in use. There are many ways and many opportunities to get good feedback about employee performance. It is important to document these methods and specific instances to supplement the more formalized process. The key is to identify them, encourage them, use them, and document the training actions that result from them. This paper describes one plant's method of getting feedback about performance of technicians in the field

  15. Enhancing Student Performance in First-Semester General Chemistry Using Active Feedback through the World Wide Web

    Science.gov (United States)

    Chambers, Kent A.; Blake, Bob

    2007-01-01

    The World Wide Web recently launched a new interactive feedback system for the instructors, so that can better understanding about their students and their problems. The feedback, in combination with tailored lectures is expected to enhance student performance in the first semester of general chemistry.

  16. Anatomy of hierarchy: Feedforward and feedback pathways in macaque visual cortex

    Science.gov (United States)

    Markov, Nikola T; Vezoli, Julien; Chameau, Pascal; Falchier, Arnaud; Quilodran, René; Huissoud, Cyril; Lamy, Camille; Misery, Pierre; Giroud, Pascale; Ullman, Shimon; Barone, Pascal; Dehay, Colette; Knoblauch, Kenneth; Kennedy, Henry

    2013-01-01

    The laminar location of the cell bodies and terminals of interareal connections determines the hierarchical structural organization of the cortex and has been intensively studied. However, we still have only a rudimentary understanding of the connectional principles of feedforward (FF) and feedback (FB) pathways. Quantitative analysis of retrograde tracers was used to extend the notion that the laminar distribution of neurons interconnecting visual areas provides an index of hierarchical distance (percentage of supragranular labeled neurons [SLN]). We show that: 1) SLN values constrain models of cortical hierarchy, revealing previously unsuspected areal relations; 2) SLN reflects the operation of a combinatorial distance rule acting differentially on sets of connections between areas; 3) Supragranular layers contain highly segregated bottom-up and top-down streams, both of which exhibit point-to-point connectivity. This contrasts with the infragranular layers, which contain diffuse bottom-up and top-down streams; 4) Cell filling of the parent neurons of FF and FB pathways provides further evidence of compartmentalization; 5) FF pathways have higher weights, cross fewer hierarchical levels, and are less numerous than FB pathways. Taken together, the present results suggest that cortical hierarchies are built from supra- and infragranular counterstreams. This compartmentalized dual counterstream organization allows point-to-point connectivity in both bottom-up and top-down directions. PMID:23983048

  17. Alpha-contingent EEG feedback reduces SPECT rCBF variability

    DEFF Research Database (Denmark)

    McLaughlin, Thomas; Steinberg, Bruce; Mulholland, Thomas

    2005-01-01

    EEG feedback methods, which link the occurrence of alpha to the presentation of repeated visual stimuli, reduce the relative variability of subsequent, alpha-blocking event durations. The temporal association between electro-cortical field activation and regional cerebral blood flow (rCBF) led us...... to investigate whether the reduced variability of alpha-blocking durations with feedback is associated with a reduction in rCBF variability. Reduced variability in the rCBF response domain under EEG feedback control might have methodological implications for future brain-imaging studies. Visual stimuli were...... to quantify the variance-reducing effects of ACS across multiple, distributed areas of the brain. Both EEG and rCBF measures demonstrated decreased variability under ACS. This improved control was seen for localized as well as anatomically distributed rCBF measures....

  18. VISUAL ART TEACHERS AND PERFORMANCE ASSESSMENT ...

    African Journals Online (AJOL)

    Charles

    qualitative research design; an aspect of descriptive survey research aiming at ... the competence and use of assessment strategies is determined by the type of ... Visual Art Teachers and Performance Assessment Methods in Nigerian Senior ...

  19. Differences in context and feedback result in different trajectories and adaptation strategies in reaching.

    Directory of Open Access Journals (Sweden)

    Fritzie Arce

    Full Text Available Computational models of motor control have often explained the straightness of horizontal planar reaching movements as a consequence of optimal control. Departure from rectilinearity is thus regarded as sub-optimal. Here we examine if subjects may instead select to make curved trajectories following adaptation to force fields and visuomotor rotations. Separate subjects adapted to force fields with or without visual feedback of their hand trajectory and were retested after 24 hours. Following adaptation, comparable accuracies were achieved in two ways: with visual feedback, adapted trajectories in force fields were straight whereas without it, they remained curved. The results suggest that trajectory shape is not always straight, but is also influenced by the calibration of available feedback signals for the state estimation required by the task. In a follow-up experiment, where additional subjects learned a visuomotor rotation immediately after force field, the trajectories learned in force fields (straight or curved were transferred when directions of the perturbations were similar but not when directions were opposing. This demonstrates a strong bias by prior experience to keep using a recently acquired control policy that continues to produce successful performance inspite of differences in tasks and feedback conditions. On relearning of force fields on the second day, facilitation by intervening visuomotor rotations occurred only when required motor adjustments and calibration of feedback signals were similar in both tasks. These results suggest that both the available feedback signals and prior history of learning influence the choice and maintenance of control policy during adaptations.

  20. Framing of Feedback Impacts Student's Satisfaction, Self-Efficacy and Performance

    Science.gov (United States)

    van de Ridder, J. M. Monica; Peters, Claudia M. M.; Stokking, Karel M.; de Ru, J. Alexander; ten Cate, Olle Th. J.

    2015-01-01

    Feedback is considered important to acquire clinical skills. Research evidence shows that feedback does not always improve learning and its effects may be small. In many studies, a variety of variables involved in feedback provision may mask either one of their effects. E.g., there is reason to believe that the way oral feedback is framed may…

  1. Advantages of externally powered prosthesis with feedback system using pseudo-cineplasty.

    Science.gov (United States)

    Nambu, Seiji; Ikebuchi, Mitsuhiko; Taniguchi, Masashi; Park, Choong Sik; Kitagawa, Takahiro; Nakajima, Shigeyoshi; Koike, Tatsuya

    2014-01-01

    Externally powered upper-limb prostheses are difficult to use because of the lack of sensory feedback. Neuroprostheses have recently been developed for people with upper-limb amputation but are complicated, expensive, and still developing. We therefore designed a simple system by combining pseudo-cineplasty with extended physiological proprioception to provide sensory feedback to the body. We penetrated the palmaris longus tendon percutaneously with a metal ring, similar to that used in body piercing, in a nondisabled subject as a pseudo-cineplasty. The tendon and ring were connected to the system, and a sensory feedback experiment was performed. We investigated the ability of the user to determine the size of an object grasped by the prosthetic hand without visual information. The subject could distinguish between large and small objects with 100% accuracy and between small, medium, and large objects with 80% accuracy. In pseudo-cineplasty, control and sensory feedback are natural because the prosthetic hand is controlled by muscle contraction. Tension transmitted from the prosthetic hand is sensed via muscle spindles and skin sensors. This technique allows only partial sensory feedback but appears to offer several advantages over other human-machine interfaces.

  2. Variations in Static Force Control and Motor Unit Behavior with Error Amplification Feedback in the Elderly

    Directory of Open Access Journals (Sweden)

    Yi-Ching Chen

    2017-11-01

    Full Text Available Error amplification (EA feedback is a promising approach to advance visuomotor skill. As error detection and visuomotor processing at short time scales decline with age, this study examined whether older adults could benefit from EA feedback that included higher-frequency information to guide a force-tracking task. Fourteen young and 14 older adults performed low-level static isometric force-tracking with visual guidance of typical visual feedback and EA feedback containing augmented high-frequency errors. Stabilogram diffusion analysis was used to characterize force fluctuation dynamics. Also, the discharge behaviors of motor units and pooled motor unit coherence were assessed following the decomposition of multi-channel surface electromyography (EMG. EA produced different behavioral and neurophysiological impacts on young and older adults. Older adults exhibited inferior task accuracy with EA feedback than with typical visual feedback, but not young adults. Although stabilogram diffusion analysis revealed that EA led to a significant decrease in critical time points for both groups, EA potentiated the critical point of force fluctuations <ΔFc2>, short-term effective diffusion coefficients (Ds, and short-term exponent scaling only for the older adults. Moreover, in older adults, EA added to the size of discharge variability of motor units and discharge regularity of cumulative discharge rate, but suppressed the pooled motor unit coherence in the 13–35 Hz band. Virtual EA alters the strategic balance between open-loop and closed-loop controls for force-tracking. Contrary to expectations, the prevailing use of closed-loop control with EA that contained high-frequency error information enhanced the motor unit discharge variability and undermined the force steadiness in the older group, concerning declines in physiological complexity in the neurobehavioral system and the common drive to the motoneuronal pool against force destabilization.

  3. Aerial somersault performance under three visual conditions.

    Science.gov (United States)

    Hondzinski, J M; Darling, W G

    2001-07-01

    Experiments were designed to examine the visual contributions to performance of back aerial double somersaults by collegiate acrobats. Somersaults were performed on a trampoline under three visual conditions: (a) NORMAL acuity; (b) REDUCED acuity (subjects wore special contacts that blocked light reflected onto the central retina); and (c) NO VISION. Videotaped skill performances were rated by two NCAA judges and digitized for kinematic analyses. Subjects' performance scores were similar in NORMAL and REDUCED conditions and lowest in the NO VISION condition. Control of body movement, indicated by time-to-contact, was most variable in the NO VISION condition. Profiles of angular head and neck velocity revealed that when subjects could see, they slowed their heads prior to touchdown in time to process optical flow information and prepare for landing. There was not always enough time to process vision associated with object identification and prepare for touchdown. It was concluded that collegiate acrobats do not need to identify objects for their best back aerial double somersault performance.

  4. The Sense of Agency Is More Sensitive to Manipulations of Outcome than Movement-Related Feedback Irrespective of Sensory Modality.

    Directory of Open Access Journals (Sweden)

    Nicole David

    Full Text Available The sense of agency describes the ability to experience oneself as the agent of one's own actions. Previous studies of the sense of agency manipulated the predicted sensory feedback related either to movement execution or to the movement's outcome, for example by delaying the movement of a virtual hand or the onset of a tone that resulted from a button press. Such temporal sensorimotor discrepancies reduce the sense of agency. It remains unclear whether movement-related feedback is processed differently than outcome-related feedback in terms of agency experience, especially if these types of feedback differ with respect to sensory modality. We employed a mixed-reality setup, in which participants tracked their finger movements by means of a virtual hand. They performed a single tap, which elicited a sound. The temporal contingency between the participants' finger movements and (i the movement of the virtual hand or (ii the expected auditory outcome was systematically varied. In a visual control experiment, the tap elicited a visual outcome. For each feedback type and participant, changes in the sense of agency were quantified using a forced-choice paradigm and the Method of Constant Stimuli. Participants were more sensitive to delays of outcome than to delays of movement execution. This effect was very similar for visual or auditory outcome delays. Our results indicate different contributions of movement- versus outcome-related sensory feedback to the sense of agency, irrespective of the modality of the outcome. We propose that this differential sensitivity reflects the behavioral importance of assessing authorship of the outcome of an action.

  5. Does Constructive Performance Feedback Improve Citizenship Intentions and Job Satisfaction? The Roles of Perceived Opportunities for Advancement, Respect, and Mood

    Science.gov (United States)

    Sommer, Kristin L.; Kulkarni, Mukta

    2012-01-01

    Organizational experts have long touted the importance of delivering negative performance feedback in a manner that enhances employee receptivity to feedback, yet the broader impacts of constructive feedback have received relatively little attention. The present investigation explored the impact of constructive, critical feedback on organizational…

  6. Traffic Visualization

    DEFF Research Database (Denmark)

    Picozzi, Matteo; Verdezoto, Nervo; Pouke, Matti

    2013-01-01

    In this paper, we present a space-time visualization to provide city's decision-makers the ability to analyse and uncover important "city events" in an understandable manner for city planning activities. An interactive Web mashup visualization is presented that integrates several visualization...... techniques to give a rapid overview of traffic data. We illustrate our approach as a case study for traffic visualization systems, using datasets from the city of Oulu that can be extended to other city planning activities. We also report the feedback of real users (traffic management employees, traffic police...

  7. Task-dependent vestibular feedback responses in reaching.

    Science.gov (United States)

    Keyser, Johannes; Medendorp, W Pieter; Selen, Luc P J

    2017-07-01

    When reaching for an earth-fixed object during self-rotation, the motor system should appropriately integrate vestibular signals and sensory predictions to compensate for the intervening motion and its induced inertial forces. While it is well established that this integration occurs rapidly, it is unknown whether vestibular feedback is specifically processed dependent on the behavioral goal. Here, we studied whether vestibular signals evoke fixed responses with the aim to preserve the hand trajectory in space or are processed more flexibly, correcting trajectories only in task-relevant spatial dimensions. We used galvanic vestibular stimulation to perturb reaching movements toward a narrow or a wide target. Results show that the same vestibular stimulation led to smaller trajectory corrections to the wide than the narrow target. We interpret this reduced compensation as a task-dependent modulation of vestibular feedback responses, tuned to minimally intervene with the task-irrelevant dimension of the reach. These task-dependent vestibular feedback corrections are in accordance with a central prediction of optimal feedback control theory and mirror the sophistication seen in feedback responses to mechanical and visual perturbations of the upper limb. NEW & NOTEWORTHY Correcting limb movements for external perturbations is a hallmark of flexible sensorimotor behavior. While visual and mechanical perturbations are corrected in a task-dependent manner, it is unclear whether a vestibular perturbation, naturally arising when the body moves, is selectively processed in reach control. We show, using galvanic vestibular stimulation, that reach corrections to vestibular perturbations are task dependent, consistent with a prediction of optimal feedback control theory. Copyright © 2017 the American Physiological Society.

  8. Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise

    Directory of Open Access Journals (Sweden)

    Wade J. Chalker

    2018-06-01

    Full Text Available Background Hamstring strain injuries (HSI are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry. Methods Using a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb’s force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to ‘reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them’. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2 using independent t-tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohen d effect size. Results There was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2–42.3 N]; P = 0.048; d = 0.61 and no significant

  9. Effects of Goal Line Feedback on Level, Slope, and Stability of Performance within Curriculum-Based Measurement.

    Science.gov (United States)

    Fuchs, Lynn S.; And Others

    1991-01-01

    Nineteen special educators implemented Curriculum-Based Measurement with a total of 36 learning-disabled math pupils in grades 2-8 to examine the effects of goal line feedback. Results indicated comparable levels and slopes of student performance across treatment conditions, although goal line feedback was associated with greater performance…

  10. The Effect of Choosing versus Receiving Feedback on College Students' Performance

    Science.gov (United States)

    Cutumisu, Maria; Schwartz, Daniel L.

    2016-01-01

    This study examines the effect of choosing versus receiving feedback on the learning performance of n = 98 post-secondary students from California on a digital poster design task. The study employs a yoked experimental design where college students are randomly assigned to play a choice-based assessment game, Posterlet, in one of two conditions,…

  11. Interactive balance training integrating sensor-based visual feedback of movement performance: a pilot study in older adults

    OpenAIRE

    Schwenk, Michael; Grewal, Gurtej S; Honarvar, Bahareh; Schwenk, Stefanie; Mohler, Jane; Khalsa, Dharma S; Najafi, Bijan

    2014-01-01

    Background Wearable sensor technology can accurately measure body motion and provide incentive feedback during exercising. The aim of this pilot study was to evaluate the effectiveness and user experience of a balance training program in older adults integrating data from wearable sensors into a human-computer interface designed for interactive training. Methods Senior living community residents (mean age 84.6) with confirmed fall risk were randomized to an intervention (IG, n?=?17) or contro...

  12. Visual and flight performance recovery after PRK or LASIK in helicopter pilots.

    Science.gov (United States)

    Van de Pol, Corina; Greig, Joanna L; Estrada, Art; Bissette, Gina M; Bower, Kraig S

    2007-06-01

    Refractive surgery, specifically photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), is becoming more accepted in the military environment. Determination of the impact on visual performance in the more demanding aviation environment was the impetus for this study. A prospective evaluation of 20 Black Hawk pilots pre-surgically and at 1 wk, 1 mo, and 6 mo postsurgery was conducted to assess both PRK and LASIK visual and flight performance outcomes on the return of aviators to duty. Of 20 pilots, 19 returned to flight status at 1 mo after surgery; 1 PRK subject was delayed due to corneal haze and subjective visual symptoms. Improvements were seen under simulator night and night vision goggle flight after LASIK; no significant changes in flight performance were measured in the aircraft. Results indicated a significantly faster recovery of all visual performance outcomes 1 wk after LASIK vs. PRK, with no difference between procedures at 1 and 6 mo. Low contrast acuity and contrast sensitivity only weakly correlated to flight performance in the early post-operative period. Overall flight performance assessed in this study after PRK and LASIK was stable or improved from baseline, indicating a resilience of performance despite measured decrements in visual performance, especially in PRK. More visually demanding flight tasks may be impacted by subtle changes in visual performance. Contrast tests are more sensitive to the effects of refractive surgical intervention and may prove to be a better indicator of visual recovery for return to flight status.

  13. Mirror reversal and visual rotation are learned and consolidated via separate mechanisms: recalibrating or learning de novo?

    Science.gov (United States)

    Telgen, Sebastian; Parvin, Darius; Diedrichsen, Jörn

    2014-10-08

    Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirror-reversal (left-right reversal over a mid-sagittal axis) of visual feedback versus rotation of visual feedback around the movement origin. During mirror-reversal learning, correct movement initiation (feedforward commands) and online corrections (feedback responses) were only generated at longer latencies. The earliest responses were directed into a nonmirrored direction, even after two training sessions. In contrast, for visual rotation learning, no dependency of directional error on reaction time emerged, and fast feedback responses to visual displacements of the cursor were immediately adapted. These results suggest that the motor system acquires a new control policy for mirror reversal, which initially requires extra processing time, while it recalibrates an existing control policy for visual rotations, exploiting established fast computational processes. Importantly, memory for visual rotation decayed between sessions, whereas memory for mirror reversals showed offline gains, leading to better performance at the beginning of the second session than in the end of the first. With shifts in time-accuracy tradeoff and offline gains, mirror-reversal learning shares common features with other skill-learning tasks. We suggest that different neuronal mechanisms underlie the recalibration of an existing versus acquisition of a new control policy and that offline gains between sessions are a characteristic of latter. Copyright © 2014 the authors 0270-6474/14/3413768-12$15.00/0.

  14. Influence of feedback characteristics on perceived learning value of feedback in clerkships: does culture matter?

    Science.gov (United States)

    Suhoyo, Yoyo; Van Hell, Elisabeth A; Kerdijk, Wouter; Emilia, Ova; Schönrock-Adema, Johanna; Kuks, Jan B M; Cohen-Schotanus, Janke

    2017-04-05

    Various feedback characteristics have been suggested to positively influence student learning. It is not clear how these feedback characteristics contribute to students' perceived learning value of feedback in cultures classified low on the cultural dimension of individualism and high on power distance. This study was conducted to validate the influence of five feedback characteristics on students' perceived learning value of feedback in an Indonesian clerkship context. We asked clerks in Neurology (n = 169) and Internal Medicine (n = 132) to assess on a 5-point Likert scale the learning value of the feedback they received. We asked them to record whether the feedback provider (1) informed the student what went well, (2) mentioned which aspects of performance needed improvement, (3) compared the student's performance to a standard, (4) further explained or demonstrated the correct performance, and (5) prepared an action plan with the student to improve performance. Data were analyzed using multilevel regression. A total of 250 students participated in this study, 131 from Internal Medicine (response rate 99%) and 119 from Neurology (response rate 70%). Of these participants, 225 respondents (44% males, 56% females) completed the form and reported 889 feedback moments. Students perceived feedback as more valuable when the feedback provider mentioned their weaknesses (β = 0.153, p learning value of feedback. No gender differences were found for perceived learning value. In Indonesia, we could validate four out of the five characteristics for effective feedback. We argue that our findings relate to culture, in particular to the levels of individualism and power distance. The recognized characteristics of what constitutes effective feedback should be validated across cultures.

  15. Robust exponential stabilization of nonholonomic wheeled mobile robots with unknown visual parameters

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The visual servoing stabilization of nonholonomic mobile robot with unknown camera parameters is investigated.A new kind of uncertain chained model of nonholonomic kinemetic system is obtained based on the visual feedback and the standard chained form of type (1,2) mobile robot.Then,a novel time-varying feedback controller is proposed for exponentially stabilizing the position and orientation of the robot using visual feedback and switching strategy when the camera parameters are not known.The exponential s...

  16. Swimming Pool Hygiene: Self-Monitoring, Task Clarification, and Performance Feedback Increase Lifeguard Cleaning Behaviors

    Science.gov (United States)

    Rose, Henry M. S.; Ludwig, Timothy D.

    2009-01-01

    The effects of task clarification, self-monitoring, and performance feedback on cleaning behaviors of 9 lifeguards in 3 performance areas (vacuuming, lobby tidying, and pool deck maintenance) were investigated using an ABA reversal design at a county swim complex. A specific task in each performance area was used as a behavioral control. Following…

  17. Love withdrawal predicts electrocortical responses to emotional faces with performance feedback: a follow-up and extension.

    Science.gov (United States)

    Huffmeijer, Renske; Bakermans-Kranenburg, Marian J; Alink, Lenneke R A; van IJzendoorn, Marinus H

    2014-06-02

    Parental use of love withdrawal is thought to affect children's later psychological functioning because it creates a link between children's performance and relational consequences. In addition, recent studies have begun to show that experiences of love withdrawal also relate to the neural processing of socio-emotional information relevant to a performance-relational consequence link, and can moderate effects of oxytocin on social information processing and behavior. The current study follows-up on our previous results by attempting to confirm and extend previous findings indicating that experiences of maternal love withdrawal are related to electrocortical responses to emotional faces presented with performance feedback. More maternal love withdrawal was related to enhanced early processing of facial feedback stimuli (reflected in more positive VPP amplitudes, and confirming previous findings). However, attentional engagement with and processing of the stimuli at a later stage were diminished in those reporting higher maternal love withdrawal (reflected in less positive LPP amplitudes, and diverging from previous findings). Maternal love withdrawal affects the processing of emotional faces presented with performance feedback differently in different stages of neural processing.

  18. Lateralized visual behavior in bottlenose dolphins (Tursiops truncatus) performing audio-visual tasks: the right visual field advantage.

    Science.gov (United States)

    Delfour, F; Marten, K

    2006-01-10

    Analyzing cerebral asymmetries in various species helps in understanding brain organization. The left and right sides of the brain (lateralization) are involved in different cognitive and sensory functions. This study focuses on dolphin visual lateralization as expressed by spontaneous eye preference when performing a complex cognitive task; we examine lateralization when processing different visual stimuli displayed on an underwater touch-screen (two-dimensional figures, three-dimensional figures and dolphin/human video sequences). Three female bottlenose dolphins (Tursiops truncatus) were submitted to a 2-, 3- or 4-, choice visual/auditory discrimination problem, without any food reward: the subjects had to correctly match visual and acoustic stimuli together. In order to visualize and to touch the underwater target, the dolphins had to come close to the touch-screen and to position themselves using monocular vision (left or right eye) and/or binocular naso-ventral vision. The results showed an ability to associate simple visual forms and auditory information using an underwater touch-screen. Moreover, the subjects showed a spontaneous tendency to use monocular vision. Contrary to previous findings, our results did not clearly demonstrate right eye preference in spontaneous choice. However, the individuals' scores of correct answers were correlated with right eye vision, demonstrating the advantage of this visual field in visual information processing and suggesting a left hemispheric dominance. We also demonstrated that the nature of the presented visual stimulus does not seem to have any influence on the animals' monocular vision choice.

  19. Alterations in Neural Control of Constant Isometric Contraction with the Size of Error Feedback.

    Directory of Open Access Journals (Sweden)

    Ing-Shiou Hwang

    Full Text Available Discharge patterns from a population of motor units (MUs were estimated with multi-channel surface electromyogram and signal processing techniques to investigate parametric differences in low-frequency force fluctuations, MU discharges, and force-discharge relation during static force-tracking with varying sizes of execution error presented via visual feedback. Fourteen healthy adults produced isometric force at 10% of maximal voluntary contraction through index abduction under three visual conditions that scaled execution errors with different amplification factors. Error-augmentation feedback that used a high amplification factor (HAF to potentiate visualized error size resulted in higher sample entropy, mean frequency, ratio of high-frequency components, and spectral dispersion of force fluctuations than those of error-reducing feedback using a low amplification factor (LAF. In the HAF condition, MUs with relatively high recruitment thresholds in the dorsal interosseous muscle exhibited a larger coefficient of variation for inter-spike intervals and a greater spectral peak of the pooled MU coherence at 13-35 Hz than did those in the LAF condition. Manipulation of the size of error feedback altered the force-discharge relation, which was characterized with non-linear approaches such as mutual information and cross sample entropy. The association of force fluctuations and global discharge trace decreased with increasing error amplification factor. Our findings provide direct neurophysiological evidence that favors motor training using error-augmentation feedback. Amplification of the visualized error size of visual feedback could enrich force gradation strategies during static force-tracking, pertaining to selective increases in the discharge variability of higher-threshold MUs that receive greater common oscillatory inputs in the β-band.

  20. Age differences in feedback reactions: The roles of employee feedback orientation on social awareness and utility.

    Science.gov (United States)

    Wang, Mo; Burlacu, Gabriela; Truxillo, Donald; James, Keith; Yao, Xiang

    2015-07-01

    Organizations worldwide are currently experiencing shifts in the age composition of their workforces. The workforce is aging and becoming increasingly age-diverse, suggesting that organizational researchers and practitioners need to better understand how age differences may manifest in the workplace and the implications for human resource practice. Integrating socioemotional selectivity theory with the performance feedback literature and using a time-lagged design, the current study examined age differences in moderating the relationships between the characteristics of performance feedback and employee reactions to the feedback event. The results suggest that older workers had higher levels of feedback orientation on social awareness, but lower levels of feedback orientation on utility than younger workers. Furthermore, the positive associations between favorability of feedback and feedback delivery and feedback reactions were stronger for older workers than for younger workers, whereas the positive association between feedback quality and feedback reactions was stronger for younger workers than for older workers. Finally, the current study revealed that age-related differences in employee feedback orientation could explain the different patterns of relationships between feedback characteristics and feedback reactions across older and younger workers. These findings have both theoretical and practical implications for building theory about workplace aging and improving ways that performance feedback is managed across employees from diverse age groups. (c) 2015 APA, all rights reserved).

  1. Pseudo-Haptic Feedback in Teleoperation.

    Science.gov (United States)

    Neupert, Carsten; Matich, Sebastian; Scherping, Nick; Kupnik, Mario; Werthschutzky, Roland; Hatzfeld, Christian

    2016-01-01

    In this paper, we develop possible realizations of pseudo-haptic feedback in teleoperation systems based on existing works for pseudo-haptic feedback in virtual reality and the intended applications. We derive four potential factors affecting the performance of haptic feedback (calculation operator, maximum displacement, offset force, and scaling factor), which are analyzed in three compliance identification experiments. First, we analyze the principle usability of pseudo-haptic feedback by comparing information transfer measures for teleoperation and direct interaction. Pseudo-haptic interaction yields well above-chance performance, while direct interaction performs almost perfectly. In order to optimize pseudo-haptic feedback, in the second study we perform a full-factorial experimental design with 36 subjects performing 6,480 trials with 36 different treatments. Information transfer ranges from 0.68 bit to 1.72 bit in a task with a theoretical maximum of 2.6 bit, with a predominant effect of the calculation operator and a minor effect of the maximum displacement. In a third study, short- and long-term learning effects are analyzed. Learning effects regarding the performance of pseudo-haptic feedback cannot be observed for single-day experiments. Tests over 10 days show a maximum increase in information transfer of 0.8 bit. The results show the feasibility of pseudo-haptic feedback for teleoperation and can be used as design basis for task-specific systems.

  2. Intensive treatment with ultrasound visual feedback for speech sound errors in childhood apraxia

    Directory of Open Access Journals (Sweden)

    Jonathan L Preston

    2016-08-01

    Full Text Available Ultrasound imaging is an adjunct to traditional speech therapy that has shown to be beneficial in the remediation of speech sound errors. Ultrasound biofeedback can be utilized during therapy to provide clients additional knowledge about their tongue shapes when attempting to produce sounds that are in error. The additional feedback may assist children with childhood apraxia of speech in stabilizing motor patterns, thereby facilitating more consistent and accurate productions of sounds and syllables. However, due to its specialized nature, ultrasound visual feedback is a technology that is not widely available to clients. Short-term intensive treatment programs are one option that can be utilized to expand access to ultrasound biofeedback. Schema-based motor learning theory suggests that short-term intensive treatment programs (massed practice may assist children in acquiring more accurate motor patterns. In this case series, three participants ages 10-14 diagnosed with childhood apraxia of speech attended 16 hours of speech therapy over a two-week period to address residual speech sound errors. Two participants had distortions on rhotic sounds, while the third participant demonstrated lateralization of sibilant sounds. During therapy, cues were provided to assist participants in obtaining a tongue shape that facilitated a correct production of the erred sound. Additional practice without ultrasound was also included. Results suggested that all participants showed signs of acquisition of sounds in error. Generalization and retention results were mixed. One participant showed generalization and retention of sounds that were treated; one showed generalization but limited retention; and the third showed no evidence of generalization or retention. Individual characteristics that may facilitate generalization are discussed. Short-term intensive treatment programs using ultrasound biofeedback may result in the acquisition of more accurate motor

  3. The Effect of Combination of Video Feedback and Audience Feedback on Social Anxiety: Preliminary Findings.

    Science.gov (United States)

    Chen, Junwen; Mak, Rebecca; Fujita, Satoko

    2015-09-01

    Although video feedback (VF) is shown to improve appraisals of social performance in socially anxious individuals, its impact on state anxiety during a social situation is mixed. The current study investigated the effect of combined video feedback and audience feedback (AF) on self-perceptions of performance and bodily sensations as well as state anxiety pertaining to a speech task. Forty-one socially anxious students were randomly allocated to combined video feedback with audience feedback (VF + AF), video feedback only (VF), audience feedback only (AF), or a control condition. Following a 3-min speech, participants in the VF + AF, VF, and AF conditions watched the videotape of their speech with cognitive preparation in the presence of three confederates who served as audience, and/or received feedback from the confederates, while the control group watched their videotaped speech without cognitive preparation. Both VF + AF and AF conditions improved distorted appraisal of performance and bodily sensations as well as state anxiety. The clinical implications of these findings are discussed. © The Author(s) 2015.

  4. Both movement-end and task-end are critical for error feedback in visuomotor adaptation: a behavioral experiment.

    Directory of Open Access Journals (Sweden)

    Takumi Ishikawa

    Full Text Available An important issue in motor learning/adaptation research is how the brain accepts the error information necessary for maintaining and improving task performance in a changing environment. The present study focuses on the effect of timing of error feedback. Previous research has demonstrated that adaptation to displacement of the visual field by prisms in a manual reaching task is significantly slowed by delayed visual feedback of the endpoint, suggesting that error feedback is most effective when given at the end of a movement. To further elucidate the brain mechanism by which error information is accepted in visuomotor adaptation, we tested whether error acceptance is linked to the end of a given task or to the end of an executed movement. We conducted a behavioral experiment using a virtual shooting task in which subjects controlled their wrist movements to meet a target with a cursor as accurately as possible. We manipulated the timing of visual feedback of the impact position so that it occurred either ahead of or behind the true time of impact. In another condition, the impact timing was explicitly indicated by an additional cue. The magnitude of the aftereffect significantly varied depending on the timing of feedback (p < 0.05, Friedman's Test. Interestingly, two distinct peaks of aftereffect were observed around movement-end and around task-end, irrespective of the existence of the timing cue. However, the peak around task-end was sharper when the timing cue was given. Our results demonstrate that the brain efficiently accepts error information at both movement-end and task-end, suggesting that two different learning mechanisms may underlie visuomotor transformation.

  5. Twelve tips to promote successful development of a learner performance dashboard within a medical education program.

    Science.gov (United States)

    Boscardin, Christy; Fergus, Kirkpatrick B; Hellevig, Bonnie; Hauer, Karen E

    2017-11-09

    Easily accessible and interpretable performance data constitute critical feedback for learners that facilitate informed self-assessment and learning planning. To provide this feedback, there has been a proliferation of educational dashboards in recent years. An educational (learner) dashboard systematically delivers timely and continuous feedback on performance and can provide easily visualized and interpreted performance data. In this paper, we provide practical tips for developing a functional, user-friendly individual learner performance dashboard and literature review of dashboard development, assessment theory, and users' perspectives. Considering key design principles and maximizing current technological advances in data visualization techniques can increase dashboard utility and enhance the user experience. By bridging current technology with assessment strategies that support learning, educators can continue to improve the field of learning analytics and design of information management tools such as dashboards in support of improved learning outcomes.

  6. Giving Feedback: Development of Scales for the Mum Effect, Discomfort Giving Feedback, and Feedback Medium Preference

    Science.gov (United States)

    Cox, Susie S.; Marler, Laura E.; Simmering, Marcia J.; Totten, Jeff W.

    2011-01-01

    Research in organizational behavior and human resources promotes the view that it is critical for managers to provide accurate feedback to employees, yet little research addresses rater tendencies (i.e., the "mum effect") and attitudes that influence how performance feedback is given. Because technology has changed the nature of…

  7. The Effect of Corrective Feedback on Performance in Basic Cognitive Tasks: An Analysis of RT Components

    Directory of Open Access Journals (Sweden)

    Carmen Moret-Tatay

    2016-12-01

    Full Text Available The current work examines the effect of trial-by-trial feedback about correct and error responding on performance in two basic cognitive tasks: a classic Stroop task (n = 40 and a color-word matching task ('n' = 30. Standard measures of both RT and accuracy were examined in addition to measures obtained from fitting the ex-Gaussian distributional model to the correct RTs. For both tasks, RTs were faster in blocks of trials with feedback than in blocks without feedback, but this difference was not significant. On the other hand, with respect to the distributional analyses, providing feedback served to significantly reduce the size of the tails of the RT distributions. Such results suggest that, for conditions in which accuracy is fairly high, the effect of corrective feedback might either be to reduce the tendency to double-check before responding or to decrease the amount of attentional lapsing.

  8. Coding the presence of visual objects in a recurrent neural network of visual cortex.

    Science.gov (United States)

    Zwickel, Timm; Wachtler, Thomas; Eckhorn, Reinhard

    2007-01-01

    Before we can recognize a visual object, our visual system has to segregate it from its background. This requires a fast mechanism for establishing the presence and location of objects independently of their identity. Recently, border-ownership neurons were recorded in monkey visual cortex which might be involved in this task [Zhou, H., Friedmann, H., von der Heydt, R., 2000. Coding of border ownership in monkey visual cortex. J. Neurosci. 20 (17), 6594-6611]. In order to explain the basic mechanisms required for fast coding of object presence, we have developed a neural network model of visual cortex consisting of three stages. Feed-forward and lateral connections support coding of Gestalt properties, including similarity, good continuation, and convexity. Neurons of the highest area respond to the presence of an object and encode its position, invariant of its form. Feedback connections to the lowest area facilitate orientation detectors activated by contours belonging to potential objects, and thus generate the experimentally observed border-ownership property. This feedback control acts fast and significantly improves the figure-ground segregation required for the consecutive task of object recognition.

  9. Feedforward and feedback motor control abnormalities implicate cerebellar dysfunctions in autism spectrum disorder.

    Science.gov (United States)

    Mosconi, Matthew W; Mohanty, Suman; Greene, Rachel K; Cook, Edwin H; Vaillancourt, David E; Sweeney, John A

    2015-02-04

    Sensorimotor abnormalities are common in autism spectrum disorder (ASD) and among the earliest manifestations of the disorder. They have been studied far less than the social-communication and cognitive deficits that define ASD, but a mechanistic understanding of sensorimotor abnormalities in ASD may provide key insights into the neural underpinnings of the disorder. In this human study, we examined rapid, precision grip force contractions to determine whether feedforward mechanisms supporting initial motor output before sensory feedback can be processed are disrupted in ASD. Sustained force contractions also were examined to determine whether reactive adjustments to ongoing motor behavior based on visual feedback are altered. Sustained force was studied across multiple force levels and visual gains to assess motor and visuomotor mechanisms, respectively. Primary force contractions of individuals with ASD showed greater peak rate of force increases and large transient overshoots. Individuals with ASD also showed increased sustained force variability that scaled with force level and was more severe when visual gain was highly amplified or highly degraded. When sustaining a constant force level, their reactive adjustments were more periodic than controls, and they showed increased reliance on slower feedback mechanisms. Feedforward and feedback mechanism alterations each were associated with more severe social-communication impairments in ASD. These findings implicate anterior cerebellar circuits involved in feedforward motor control and posterior cerebellar circuits involved in transforming visual feedback into precise motor adjustments in ASD. Copyright © 2015 the authors 0270-6474/15/352015-11$15.00/0.

  10. Comparing three CPR feedback devices and standard BLS in a single rescuer scenario: a randomised simulation study.

    Science.gov (United States)

    Zapletal, Bernhard; Greif, Robert; Stumpf, Dominik; Nierscher, Franz Josef; Frantal, Sophie; Haugk, Moritz; Ruetzler, Kurt; Schlimp, Christoph; Fischer, Henrik

    2014-04-01

    Efficiently performed basic life support (BLS) after cardiac arrest is proven to be effective. However, cardiopulmonary resuscitation (CPR) is strenuous and rescuers' performance declines rapidly over time. Audio-visual feedback devices reporting CPR quality may prevent this decline. We aimed to investigate the effect of various CPR feedback devices on CPR quality. In this open, prospective, randomised, controlled trial we compared three CPR feedback devices (PocketCPR, CPRmeter, iPhone app PocketCPR) with standard BLS without feedback in a simulated scenario. 240 trained medical students performed single rescuer BLS on a manikin for 8min. Effective compression (compressions with correct depth, pressure point and sufficient decompression) as well as compression rate, flow time fraction and ventilation parameters were compared between the four groups. Study participants using the PocketCPR performed 17±19% effective compressions compared to 32±28% with CPRmeter, 25±27% with the iPhone app PocketCPR, and 35±30% applying standard BLS (PocketCPR vs. CPRmeter p=0.007, PocketCPR vs. standard BLS p=0.001, others: ns). PocketCPR and CPRmeter prevented a decline in effective compression over time, but overall performance in the PocketCPR group was considerably inferior to standard BLS. Compression depth and rate were within the range recommended in the guidelines in all groups. While we found differences between the investigated CPR feedback devices, overall BLS quality was suboptimal in all groups. Surprisingly, effective compression was not improved by any CPR feedback device compared to standard BLS. All feedback devices caused substantial delay in starting CPR, which may worsen outcome. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance.

    Science.gov (United States)

    Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M; Latash, Mark L

    2017-02-01

    We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force-moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task.

  12. What higher education students do with teacher feedback: Feedback ...

    African Journals Online (AJOL)

    Writing pedagogy research has constantly maintained that feedback is 'an essential component of virtually every model of the writing process' (Hall, 1990: 43) as it motivates writers to improve their next draft. Feedback during the writing process improves not only student attitude to writing but writing performance if students ...

  13. High performance visual display for HENP detectors

    CERN Document Server

    McGuigan, M; Spiletic, J; Fine, V; Nevski, P

    2001-01-01

    A high end visual display for High Energy Nuclear Physics (HENP) detectors is necessary because of the sheer size and complexity of the detector. For BNL this display will be of special interest because of STAR and ATLAS. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. To visualize the HENP detectors with maximal performance we have developed software with the following characteristics. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc, to avoid conflicting with the many graphic development groups associated with specific detectors like STAR and ATLAS. We develop advanced OpenGL features such as transparency and polarized stereoscopy. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We construct enhanced interactiv...

  14. Development of the Teacher Feedback Observation Scheme: evaluating the quality of feedback in peer groups

    NARCIS (Netherlands)

    Thurlings, Marieke; Vermeulen, Marjan; Kreijns, Karel; Bastiaens, Theo; Stijnen, Sjef

    2018-01-01

    Research suggests that feedback is an essential element in learning. This study focuses on feedback that teachers provide in reciprocal peer groups to improve their performance in the classroom. The Teacher Feedback Observation Scheme (TFOS) was developed to identify feedback patterns, which

  15. Feedback effects on students' writing motivation, process, and performance

    NARCIS (Netherlands)

    Duijnhouwer, H.

    2010-01-01

    Many students’ writing capacities remain insufficient during college years (Kellogg & Whiteford, 2009). Teachers try to improve students’ writing skills by providing them with feedback on their texts. Remarkably, research on the effects of feedback provided on written products is scarce (Graham &

  16. High Performance Molecular Visualization: In-Situ and Parallel Rendering with EGL

    Science.gov (United States)

    Stone, John E.; Messmer, Peter; Sisneros, Robert; Schulten, Klaus

    2016-01-01

    Large scale molecular dynamics simulations produce terabytes of data that is impractical to transfer to remote facilities. It is therefore necessary to perform visualization tasks in-situ as the data are generated, or by running interactive remote visualization sessions and batch analyses co-located with direct access to high performance storage systems. A significant challenge for deploying visualization software within clouds, clusters, and supercomputers involves the operating system software required to initialize and manage graphics acceleration hardware. Recently, it has become possible for applications to use the Embedded-system Graphics Library (EGL) to eliminate the requirement for windowing system software on compute nodes, thereby eliminating a significant obstacle to broader use of high performance visualization applications. We outline the potential benefits of this approach in the context of visualization applications used in the cloud, on commodity clusters, and supercomputers. We discuss the implementation of EGL support in VMD, a widely used molecular visualization application, and we outline benefits of the approach for molecular visualization tasks on petascale computers, clouds, and remote visualization servers. We then provide a brief evaluation of the use of EGL in VMD, with tests using developmental graphics drivers on conventional workstations and on Amazon EC2 G2 GPU-accelerated cloud instance types. We expect that the techniques described here will be of broad benefit to many other visualization applications. PMID:27747137

  17. Feedback from visual cortical area 7 to areas 17 and 18 in cats: How neural web is woven during feedback.

    Science.gov (United States)

    Yang, X; Ding, H; Lu, J

    2016-01-15

    To investigate the feedback effect from area 7 to areas 17 and 18, intrinsic signal optical imaging combined with pharmacological, morphological methods and functional magnetic resonance imaging (fMRI) was employed. A spatial frequency-dependent decrease in response amplitude of orientation maps was observed in areas 17 and 18 when area 7 was inactivated by a local injection of GABA, or by a lesion induced by liquid nitrogen freezing. The pattern of orientation maps of areas 17 and 18 after the inactivation of area 7, if they were not totally blurred, paralleled the normal one. In morphological experiments, after one point at the shallow layers within the center of the cat's orientation column of area 17 was injected electrophoretically with HRP (horseradish peroxidase), three sequential patches in layers 1, 2 and 3 of area 7 were observed. Employing fMRI it was found that area 7 feedbacks mainly to areas 17 and 18 on ipsilateral hemisphere. Therefore, our conclusions are: (1) feedback from area 7 to areas 17 and 18 is spatial frequency modulated; (2) feedback from area 7 to areas 17 and 18 occurs mainly ipsilaterally; (3) histological feedback pattern from area 7 to area 17 is weblike. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. The Best Achievable ℋ2 Tracking Performances for SIMO Feedback Control Systems

    Directory of Open Access Journals (Sweden)

    Shinji Hara

    2007-01-01

    Full Text Available This paper is concerned with the inherent ℋ2 tracking performance limitation of single-input and multiple-output (SIMO linear time-invariant (LTI feedback control systems. The performance is measured by the tracking error between a step reference input and the plant output with additional penalty on control input. We employ the plant augmentation strategy, which enables us to derive analytical closed-form expressions of the best achievable performance not only for discrete-time system, but also for continuous-time system by exploiting the delta domain version of the expressions.

  19. The impact of force feedback level on steering performance

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.

    2013-01-01

    Steer-by-wire systems provide designers the ability to customize and personalize force feedback on the steering wheel, based on individual preferences. Earlier studies using subjective responses have shown that there are individual differences in preferences for force feedback. It has also been

  20. Sensory threshold neuromuscular electrical stimulation fosters motor imagery performance.

    Science.gov (United States)

    Corbet, Tiffany; Iturrate, Iñaki; Pereira, Michael; Perdikis, Serafeim; Millán, José Del R

    2018-04-21

    Motor imagery (MI) has been largely studied as a way to enhance motor learning and to restore motor functions. Although it is agreed that users should emphasize kinesthetic imagery during MI, recordings of MI brain patterns are not sufficiently reliable for many subjects. It has been suggested that the usage of somatosensory feedback would be more suitable than standardly used visual feedback to enhance MI brain patterns. However, somatosensory feed-back should not interfere with the recorded MI brain pattern. In this study we propose a novel feedback modality to guide subjects during MI based on sensory threshold neuromuscular electrical stimulation (St-NMES). St-NMES depolarizes sensory and motor axons without eliciting any muscular contraction. We hypothesize that St-NMES does not induce detectable ERD brain patterns and fosters MI performance. Twelve novice subjects were included in a cross-over design study. We recorded their EEG, comparing St-NMES with visual feed-back during MI or resting tasks. We found that St-NMES not only induced significantly larger desynchronization over sensorimotor areas (p<0.05) but also significantly enhanced MI brain connectivity patterns. Moreover, classification accuracy and stability were significantly higher with St-NMES. Importantly, St-NMES alone did not induce detectable artifacts, but rather the changes in the detected patterns were due to an increased MI performance. Our findings indicate that St-NMES is a promising feedback in order to foster MI performance and cold be used for BMI online applications. Copyright © 2018. Published by Elsevier Inc.

  1. About Politeness, Face, and Feedback: Exploring Resident and Faculty Perceptions of How Institutional Feedback Culture Influences Feedback Practices.

    Science.gov (United States)

    Ramani, Subha; Könings, Karen D; Mann, Karen V; Pisarski, Emily E; van der Vleuten, Cees P M

    2018-03-06

    To explore resident and faculty perspectives on what constitutes feedback culture, their perceptions of how institutional feedback culture (including politeness concepts) might influence the quality and impact of feedback, feedback seeking, receptivity, and readiness to engage in bidirectional feedback. Using a constructivist grounded theory approach, five focus group discussions with internal medicine residents, three focus group discussions with general medicine faculty, and eight individual interviews with subspecialist faculty were conducted at Brigham and Women's Hospital between April and December 2016. Discussions and interviews were audiotaped and transcribed verbatim; concurrent data collection and analysis were performed using the constant comparative approach. Analysis was considered through the lens of politeness theory and organizational culture. Twenty-nine residents and twenty-two general medicine faculty participated in focus group discussions, and eight subspecialty faculty participated in interviews. The institutional feedback culture was described by participants as: (1) a culture of politeness, in which language potentially damaging to residents' self-esteem was discouraged, and (2) a culture of excellence, in which the institution's outstanding reputation and pedigree of trainees inhibited constructive feedback. Three key themes situated within this broader cultural context were discovered: normalizing constructive feedback to promote a culture of growth, overcoming the mental block to feedback seeking, and hierarchical culture impeding bidirectional feedback. An institutional feedback culture of excellence and politeness may impede honest, meaningful feedback and may impact feedback seeking, receptivity, and bidirectional feedback exchanges. It is essential to understand the institutional feedback culture before it can be successfully changed.

  2. Designing feedback to mitigate teen distracted driving: A social norms approach.

    Science.gov (United States)

    Merrikhpour, Maryam; Donmez, Birsen

    2017-07-01

    The purpose of this research is to investigate teens' perceived social norms and whether providing normative information can reduce distracted driving behaviors among them. Parents are among the most important social referents for teens; they have significant influences on teens' driving behaviors, including distracted driving which significantly contributes to teens' crash risks. Social norms interventions have been successfully applied in various domains including driving; however, this approach is yet to be explored for mitigating driver distraction among teens. Forty teens completed a driving simulator experiment while performing a self-paced visual-manual secondary task in four between-subject conditions: a) social norms feedback that provided a report at the end of each drive on teens' distracted driving behavior, comparing their distraction engagement to their parent's, b) post-drive feedback that provided just the report on teens' distracted driving behavior without information on their parents, c) real-time feedback in the form of auditory warnings based on eyes of road-time, and d) no feedback as control. Questionnaires were administered to collect data on these teens' and their parents' self-reported engagement in driver distractions and the associated social norms. Social norms and real-time feedback conditions resulted in significantly smaller average off-road glance duration, rate of long (>2s) off-road glances, and standard deviation of lane position compared to no feedback. Further, social norms feedback decreased brake response time and percentage of time not looking at the road compared to no feedback. No major effect was observed for post-drive feedback. Questionnaire results suggest that teens appeared to overestimate parental norms, but no effect of feedback was found on their perceptions. Feedback systems that leverage social norms can help mitigate driver distraction among teens. Overall, both social norms and real-time feedback induced

  3. The effects of substitute multisensory feedback on task performance and the sense of presence in a virtual reality environment

    Science.gov (United States)

    Milella, Ferdinando; Pinto, Carlo; Cant, Iain; White, Mark; Meyer, Georg

    2018-01-01

    Objective and subjective measures of performance in virtual reality environments increase as more sensory cues are delivered and as simulation fidelity increases. Some cues (colour or sound) are easier to present than others (object weight, vestibular cues) so that substitute cues can be used to enhance informational content in a simulation at the expense of simulation fidelity. This study evaluates how substituting cues in one modality by alternative cues in another modality affects subjective and objective performance measures in a highly immersive virtual reality environment. Participants performed a wheel change in a virtual reality (VR) environment. Auditory, haptic and visual cues, signalling critical events in the simulation, were manipulated in a factorial design. Subjective ratings were recorded via questionnaires. The time taken to complete the task was used as an objective performance measure. The results show that participants performed best and felt an increased sense of immersion and involvement, collectively referred to as ‘presence’, when substitute multimodal sensory feedback was provided. Significant main effects of audio and tactile cues on task performance and on participants' subjective ratings were found. A significant negative relationship was found between the objective (overall completion times) and subjective (ratings of presence) performance measures. We conclude that increasing informational content, even if it disrupts fidelity, enhances performance and user’s overall experience. On this basis we advocate the use of substitute cues in VR environments as an efficient method to enhance performance and user experience. PMID:29390023

  4. The effects of substitute multisensory feedback on task performance and the sense of presence in a virtual reality environment.

    Science.gov (United States)

    Cooper, Natalia; Milella, Ferdinando; Pinto, Carlo; Cant, Iain; White, Mark; Meyer, Georg

    2018-01-01

    Objective and subjective measures of performance in virtual reality environments increase as more sensory cues are delivered and as simulation fidelity increases. Some cues (colour or sound) are easier to present than others (object weight, vestibular cues) so that substitute cues can be used to enhance informational content in a simulation at the expense of simulation fidelity. This study evaluates how substituting cues in one modality by alternative cues in another modality affects subjective and objective performance measures in a highly immersive virtual reality environment. Participants performed a wheel change in a virtual reality (VR) environment. Auditory, haptic and visual cues, signalling critical events in the simulation, were manipulated in a factorial design. Subjective ratings were recorded via questionnaires. The time taken to complete the task was used as an objective performance measure. The results show that participants performed best and felt an increased sense of immersion and involvement, collectively referred to as 'presence', when substitute multimodal sensory feedback was provided. Significant main effects of audio and tactile cues on task performance and on participants' subjective ratings were found. A significant negative relationship was found between the objective (overall completion times) and subjective (ratings of presence) performance measures. We conclude that increasing informational content, even if it disrupts fidelity, enhances performance and user's overall experience. On this basis we advocate the use of substitute cues in VR environments as an efficient method to enhance performance and user experience.

  5. The effects of substitute multisensory feedback on task performance and the sense of presence in a virtual reality environment.

    Directory of Open Access Journals (Sweden)

    Natalia Cooper

    Full Text Available Objective and subjective measures of performance in virtual reality environments increase as more sensory cues are delivered and as simulation fidelity increases. Some cues (colour or sound are easier to present than others (object weight, vestibular cues so that substitute cues can be used to enhance informational content in a simulation at the expense of simulation fidelity. This study evaluates how substituting cues in one modality by alternative cues in another modality affects subjective and objective performance measures in a highly immersive virtual reality environment. Participants performed a wheel change in a virtual reality (VR environment. Auditory, haptic and visual cues, signalling critical events in the simulation, were manipulated in a factorial design. Subjective ratings were recorded via questionnaires. The time taken to complete the task was used as an objective performance measure. The results show that participants performed best and felt an increased sense of immersion and involvement, collectively referred to as 'presence', when substitute multimodal sensory feedback was provided. Significant main effects of audio and tactile cues on task performance and on participants' subjective ratings were found. A significant negative relationship was found between the objective (overall completion times and subjective (ratings of presence performance measures. We conclude that increasing informational content, even if it disrupts fidelity, enhances performance and user's overall experience. On this basis we advocate the use of substitute cues in VR environments as an efficient method to enhance performance and user experience.

  6. Severe hypoxia affects exercise performance independently of afferent feedback and peripheral fatigue.

    Science.gov (United States)

    Millet, Guillaume Y; Muthalib, Makii; Jubeau, Marc; Laursen, Paul B; Nosaka, Kazunori

    2012-04-01

    To test the hypothesis that hypoxia centrally affects performance independently of afferent feedback and peripheral fatigue, we conducted two experiments under complete vascular occlusion of the exercising muscle under different systemic O(2) environmental conditions. In experiment 1, 12 subjects performed repeated submaximal isometric contractions of the elbow flexor to exhaustion (RCTE) with inspired O(2) fraction fixed at 9% (severe hypoxia, SevHyp), 14% (moderate hypoxia, ModHyp), 21% (normoxia, Norm), or 30% (hyperoxia, Hyper). The number of contractions (performance), muscle (biceps brachii), and prefrontal near-infrared spectroscopy (NIRS) parameters and high-frequency paired-pulse (PS100) evoked responses to electrical muscle stimulation were monitored. In experiment 2, 10 subjects performed another RCTE in SevHyp and Norm conditions in which the number of contractions, biceps brachii electromyography responses to electrical nerve stimulation (M wave), and transcranial magnetic stimulation responses (motor-evoked potentials, MEP, and cortical silent period, CSP) were recorded. Performance during RCTE was significantly reduced by 10-15% in SevHyp (arterial O(2) saturation, SpO(2) = ∼75%) compared with ModHyp (SpO(2) = ∼90%) or Norm/Hyper (SpO(2) > 97%). Performance reduction in SevHyp occurred despite similar 1) metabolic (muscle NIRS parameters) and functional (changes in PS100 and M wave) muscle states and 2) MEP and CSP responses, suggesting comparable corticospinal excitability and spinal and cortical inhibition between SevHyp and Norm. It is concluded that, in SevHyp, performance and central drive can be altered independently of afferent feedback and peripheral fatigue. It is concluded that submaximal performance in SevHyp is partly reduced by a mechanism related directly to brain oxygenation.

  7. Shape representation modulating the effect of motion on visual search performance.

    Science.gov (United States)

    Yang, Lindong; Yu, Ruifeng; Lin, Xuelian; Liu, Na

    2017-11-02

    The effect of motion on visual search has been extensively investigated, but that of uniform linear motion of display on search performance for tasks with different target-distractor shape representations has been rarely explored. The present study conducted three visual search experiments. In Experiments 1 and 2, participants finished two search tasks that differed in target-distractor shape representations under static and dynamic conditions. Two tasks with clear and blurred stimuli were performed in Experiment 3. The experiments revealed that target-distractor shape representation modulated the effect of motion on visual search performance. For tasks with low target-distractor shape similarity, motion negatively affected search performance, which was consistent with previous studies. However, for tasks with high target-distractor shape similarity, if the target differed from distractors in that a gap with a linear contour was added to the target, and the corresponding part of distractors had a curved contour, motion positively influenced search performance. Motion blur contributed to the performance enhancement under dynamic conditions. The findings are useful for understanding the influence of target-distractor shape representation on dynamic visual search performance when display had uniform linear motion.

  8. Multi-bunch Feedback Systems

    International Nuclear Information System (INIS)

    Lonza, M; Schmickler, H

    2014-01-01

    Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. We first introduce coupled-bunch instabilities, analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedback systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main components of a feedback system and the related issues will also be analysed. Finally, we shall focus on digital feedback systems, their characteristics, and features, as well as on how they can be concretely exploited for both the optimization of feedback performance and for beam dynamics studies

  9. Does accelerometer feedback on high-quality chest compression improve survival rate? An in-hospital cardiac arrest simulation.

    Science.gov (United States)

    Jung, Min Hee; Oh, Je Hyeok; Kim, Chan Woong; Kim, Sung Eun; Lee, Dong Hoon; Chang, Wen Joen

    2015-08-01

    We investigated whether visual feedback from an accelerometer device facilitated high-quality chest compressions during an in-hospital cardiac arrest simulation using a manikin. Thirty health care providers participated in an in-hospital cardiac arrest simulation with 1 minute of continuous chest compressions. Chest compressions were performed on a manikin lying on a bed according to visual feedback from an accelerometer feedback device. The manikin and accelerometer recorded chest compression data simultaneously. The simulated patient was deemed to have survived when the chest compression data satisfied all of the preset high-quality chest compression criteria (depth ≥51 mm, rate >100 per minute, and ≥95% full recoil). Survival rates were calculated from the feedback device and manikin data. The survival rate according to the feedback device data was 80%; however, the manikin data indicated a significantly lower survival rate (46.7%; P = .015). The difference between the accelerometer and manikin survival rates was not significant for participants with a body mass index greater than or equal to 20 kg/m(2) (93.3 vs 73.3%, respectively; P = .330); however, the difference in survival rate was significant in participants with body mass index less than 20 kg/m(2) (66.7 vs 20.0%, respectively; P = .025). The use of accelerometer feedback devices to facilitate high-quality chest compression may not be appropriate for lightweight rescuers because of the potential for compression depth overestimation. Clinical Research Information Service (KCT0001449). Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features.

    Science.gov (United States)

    Han, Chang-Hee; Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan; Im, Chang-Hwan

    2016-01-01

    It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

  11. The impact of online video lecture recordings and automated feedback on student performance

    NARCIS (Netherlands)

    Wieling, M. B.; Hofman, W. H. A.

    To what extent a blended learning configuration of face-to-face lectures, online on-demand video recordings of the face-to-face lectures and the offering of online quizzes with appropriate feedback has an additional positive impact on the performance of these students compared to the traditional

  12. Spatial frequency-dependent feedback of visual cortical area 21a modulating functional orientation column maps in areas 17 and 18 of the cat.

    Science.gov (United States)

    Huang, Luoxiu; Chen, Xin; Shou, Tiande

    2004-02-20

    The feedback effect of activity of area 21a on orientation maps of areas 17 and 18 was investigated in cats using intrinsic signal optical imaging. A spatial frequency-dependent decrease in response amplitude of orientation maps to grating stimuli was observed in areas 17 and 18 when area 21a was inactivated by local injection of GABA, or by a lesion induced by liquid nitrogen freezing. The decrease in response amplitude of orientation maps of areas 17 and 18 after the area 21a inactivation paralleled the normal response without the inactivation. Application in area 21a of bicuculline, a GABAa receptor antagonist caused an increase in response amplitude of orientation maps of area 17. The results indicate a positive feedback from high-order visual cortical area 21a to lower-order areas underlying a spatial frequency-dependent mechanism.

  13. Using Goals, Feedback, Reinforcement, and a Performance Matrix to Improve Customer Service in a Large Department Store

    Science.gov (United States)

    Eikenhout, Nelson; Austin, John

    2005-01-01

    This study employed an ABAC and multiple baseline design to evaluate the effects of (B) feedback and (C) a package of feedback, goalsetting, and reinforcement (supervisor praise and an area-wide celebration as managed through a performance matrix, on a total of 14 various customer service behaviors for a total of 115 employees at a large…

  14. Isolating Visual and Proprioceptive Components of Motor Sequence Learning in ASD.

    Science.gov (United States)

    Sharer, Elizabeth A; Mostofsky, Stewart H; Pascual-Leone, Alvaro; Oberman, Lindsay M

    2016-05-01

    In addition to defining impairments in social communication skills, individuals with autism spectrum disorder (ASD) also show impairments in more basic sensory and motor skills. Development of new skills involves integrating information from multiple sensory modalities. This input is then used to form internal models of action that can be accessed when both performing skilled movements, as well as understanding those actions performed by others. Learning skilled gestures is particularly reliant on integration of visual and proprioceptive input. We used a modified serial reaction time task (SRTT) to decompose proprioceptive and visual components and examine whether patterns of implicit motor skill learning differ in ASD participants as compared with healthy controls. While both groups learned the implicit motor sequence during training, healthy controls showed robust generalization whereas ASD participants demonstrated little generalization when visual input was constant. In contrast, no group differences in generalization were observed when proprioceptive input was constant, with both groups showing limited degrees of generalization. The findings suggest, when learning a motor sequence, individuals with ASD tend to rely less on visual feedback than do healthy controls. Visuomotor representations are considered to underlie imitative learning and action understanding and are thereby crucial to social skill and cognitive development. Thus, anomalous patterns of implicit motor learning, with a tendency to discount visual feedback, may be an important contributor in core social communication deficits that characterize ASD. Autism Res 2016, 9: 563-569. © 2015 International Society for Autism Research, Wiley Periodicals, Inc. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

  15. Feedback For Helpers

    Science.gov (United States)

    Stromer, Walter F.

    1975-01-01

    The author offers some feedback to those in the helping professions in three areas: (1) forms and letters; (2) jumping to conclusions; and (3) blaming and belittling, in hopes of stimulating more feedback as well as more positive ways of performing their services. (HMV)

  16. Alpha-Band Rhythms in Visual Task Performance: Phase-Locking by Rhythmic Sensory Stimulation

    Science.gov (United States)

    de Graaf, Tom A.; Gross, Joachim; Paterson, Gavin; Rusch, Tessa; Sack, Alexander T.; Thut, Gregor

    2013-01-01

    Oscillations are an important aspect of neuronal activity. Interestingly, oscillatory patterns are also observed in behaviour, such as in visual performance measures after the presentation of a brief sensory event in the visual or another modality. These oscillations in visual performance cycle at the typical frequencies of brain rhythms, suggesting that perception may be closely linked to brain oscillations. We here investigated this link for a prominent rhythm of the visual system (the alpha-rhythm, 8–12 Hz) by applying rhythmic visual stimulation at alpha-frequency (10.6 Hz), known to lead to a resonance response in visual areas, and testing its effects on subsequent visual target discrimination. Our data show that rhythmic visual stimulation at 10.6 Hz: 1) has specific behavioral consequences, relative to stimulation at control frequencies (3.9 Hz, 7.1 Hz, 14.2 Hz), and 2) leads to alpha-band oscillations in visual performance measures, that 3) correlate in precise frequency across individuals with resting alpha-rhythms recorded over parieto-occipital areas. The most parsimonious explanation for these three findings is entrainment (phase-locking) of ongoing perceptually relevant alpha-band brain oscillations by rhythmic sensory events. These findings are in line with occipital alpha-oscillations underlying periodicity in visual performance, and suggest that rhythmic stimulation at frequencies of intrinsic brain-rhythms can be used to reveal influences of these rhythms on task performance to study their functional roles. PMID:23555873

  17. Effect of prematurity and low birth weight in visual abilities and school performance.

    Science.gov (United States)

    Perez-Roche, T; Altemir, I; Giménez, G; Prieto, E; González, I; Peña-Segura, J L; Castillo, O; Pueyo, V

    2016-12-01

    Prematurity and low birth weight are known risk factors for cognitive and developmental impairments, and school failure. Visual perceptual and visual motor skills seem to be among the most affected cognitive domains in these children. To assess the influence of prematurity and low birth weight in visual cognitive skills and school performance. We performed a prospective cohort study, which included 80 boys and girls in an age range from 5 to 13. Subjects were grouped by gestational age at birth (preterm, birth weight (small for gestational age (SGA), school performance in children. Figure-ground skill and visual motor integration were significantly decreased in the preterm birth group, compared with term control subjects (figure-ground: 45.7 vs 66.5, p=0.012; visual motor integration, TVAS: (9.9 vs 11.8, p=0.018), while outcomes of visual memory (29.0 vs 47.7, p=0.012), form constancy (33.3 vs 52.8, p=0.019), figure-ground (37.4 vs 65.6, p=0.001), and visual closure (43.7 vs 62.6 p=0.016) testing were lower in the SGA (vs AGA) group. Visual cognitive difficulties corresponded with worse performance in mathematics (r=0.414, p=0.004) and reading (r=0.343, p=0.018). Specific patterns of visual perceptual and visual motor deficits are displayed by children born preterm or SGA, which hinder mathematics and reading performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Systematic tracking, visualizing, and interpreting of consumer feedback for drinking water quality.

    Science.gov (United States)

    Dietrich, Andrea M; Phetxumphou, Katherine; Gallagher, Daniel L

    2014-12-01

    Consumer feedback and complaints provide utilities with useful data about consumer perceptions of aesthetic water quality in the distribution system. This research provides a systematic approach to interpret consumer complaint water quality data provided by four water utilities that recorded consumer complaints, but did not routinely process the data. The utilities tended to write down a myriad of descriptors that were too numerous or contained a variety of spellings so that electronic "harvesting" was not possible and much manual labor was required to categorize the complaints into majors areas, such as suggested by the Drinking Water Taste and Odor Wheel or existing check-sheets. When the consumer complaint data were categorized and visualized using spider (or radar) and run-time plots, major taste, odor, and appearance patterns emerged that clarified the issue and could provide guidance to the utility on the nature and extent of the problem. A caveat is that while humans readily identify visual issues with the water, such as color, cloudiness, or rust, describing specific tastes and odors in drinking water is acknowledged to be much more difficult for humans to achieve without training. This was demonstrated with two utility groups and a group of consumers identifying the odors of orange, 2-methylisoborneol, and dimethyl trisulfide. All three groups readily and succinctly identified the familiar orange odor. The two utility groups were much more able to identify the musty odor of 2-methylisoborneol, which was likely familiar to them from their work with raw and finished water. Dimethyl trisulfide, a garlic-onion odor associated with sulfur compounds in drinking water, was the least familiar to all three groups, although the laboratory staff did best. These results indicate that utility personnel should be tolerant of consumers who can assuredly say the water is different, but cannot describe the problem. Also, it indicates that a T&O program at a utility would

  19. Direct Visual Editing of Node Attributes in Graphs

    Directory of Open Access Journals (Sweden)

    Christian Eichner

    2016-10-01

    Full Text Available There are many expressive visualization techniques for analyzing graphs. Yet, there is only little research on how existing visual representations can be employed to support data editing. An increasingly relevant task when working with graphs is the editing of node attributes. We propose an integrated visualize-and-edit approach to editing attribute values via direct interaction with the visual representation. The visualize part is based on node-link diagrams paired with attribute-dependent layouts. The edit part is as easy as moving nodes via drag-and-drop gestures. We present dedicated interaction techniques for editing quantitative as well as qualitative attribute data values. The benefit of our novel integrated approach is that one can directly edit the data while the visualization constantly provides feedback on the implications of the data modifications. Preliminary user feedback indicates that our integrated approach can be a useful complement to standard non-visual editing via external tools.

  20. High performance visual display for HENP detectors

    International Nuclear Information System (INIS)

    McGuigan, Michael; Smith, Gordon; Spiletic, John; Fine, Valeri; Nevski, Pavel

    2001-01-01

    A high end visual display for High Energy Nuclear Physics (HENP) detectors is necessary because of the sheer size and complexity of the detector. For BNL this display will be of special interest because of STAR and ATLAS. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. To visualize the HENP detectors with maximal performance we have developed software with the following characteristics. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc, to avoid conflicting with the many graphic development groups associated with specific detectors like STAR and ATLAS. We develop advanced OpenGL features such as transparency and polarized stereoscopy. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We construct enhanced interactive control, including the ability to slice, search and mark areas of the detector. We incorporate the ability to make a high quality still image of a view of the detector and the ability to generate animations and a fly through of the detector and output these to MPEG or VRML models. We develop data compression hardware and software so that remote interactive visualization will be possible among dispersed collaborators. We obtain real time visual display for events accumulated during simulations

  1. Fast feedback for linear colliders

    International Nuclear Information System (INIS)

    Hendrickson, L.; Adolphsen, C.; Allison, S.; Gromme, T.; Grossberg, P.; Himel, T.; Krauter, K.; MacKenzie, R.; Minty, M.; Sass, R.

    1995-01-01

    A fast feedback system provides beam stabilization for the SLC. As the SLC is in some sense a prototype for future linear colliders, this system may be a prototype for future feedbacks. The SLC provides a good base of experience for feedback requirements and capabilities as well as a testing ground for performance characteristics. The feedback system controls a wide variety of machine parameters throughout the SLC and associated experiments, including regulation of beam position, angle, energy, intensity and timing parameters. The design and applications of the system are described, in addition to results of recent performance studies

  2. Who wants feedback? An investigation of the variables influencing residents' feedback-seeking behavior in relation to night shifts.

    Science.gov (United States)

    Teunissen, Pim W; Stapel, Diederik A; van der Vleuten, Cees; Scherpbier, Albert; Boor, Klarke; Scheele, Fedde

    2009-07-01

    The literature on feedback in clinical medical education has predominantly treated trainees as passive recipients. Past research has focused on how clinical supervisors can use feedback to improve a trainee's performance. On the basis of research in social and organizational psychology, the authors reconceptualized residents as active seekers of feedback. They investigated what individual and situational variables influence residents' feedback-seeking behavior on night shifts. Early in 2008, the authors sent obstetrics-gynecology residents in the Netherlands--both those in their first two years of graduate training and those gaining experience between undergraduate and graduate training--a questionnaire that assessed four predictor variables (learning and performance goal orientation, and instrumental and supportive leadership), two mediator variables (perceived feedback benefits and costs), and two outcome variables (frequency of feedback inquiry and monitoring). They used structural equation modeling software to test a hypothesized model of relationships between variables. The response rate was 76.5%. Results showed that residents who perceive more feedback benefits report a higher frequency of feedback inquiry and monitoring. More perceived feedback costs result mainly in more feedback monitoring. Residents with a higher learning goal orientation perceive more feedback benefits and fewer costs. Residents with a higher performance goal orientation perceive more feedback costs. Supportive physicians lead residents to perceive more feedback benefits and fewer costs. This study showed that some residents actively seek feedback. Residents' feedback-seeking behavior partially depends on attending physicians' supervisory style. Residents' goal orientations influence their perceptions of the benefits and costs of feedback-seeking.

  3. Effects of Informative and Confirmatory Feedback on Brain Activation During Negative Feedback Processing

    Directory of Open Access Journals (Sweden)

    Yeon-Kyoung eWoo

    2015-06-01

    Full Text Available The current study compared the effects of informative and confirmatory feedback on brain activation during negative feedback processing. For confirmatory feedback trials, participants were informed that they had failed the task, whereas informative feedback trials presented task relevant information along with the notification of their failure. Fourteen male undergraduates performed a series of spatial-perceptual tasks and received feedback while their brain activity was recorded. During confirmatory feedback trials, greater activations in the amygdala, dorsal anterior cingulate cortex, and the thalamus (including the habenular were observed in response to incorrect responses. These results suggest that confirmatory feedback induces negative emotional reactions to failure. In contrast, informative feedback trials elicited greater activity in the dorsolateral prefrontal cortex (DLPFC when participants experienced failure. Further psychophysiological interaction (PPI analysis revealed a negative coupling between the DLPFC and the amygdala during informative feedback relative to confirmatory feedback trials. These findings suggest that providing task-relevant information could facilitate implicit down-regulation of negative emotions following failure.

  4. From Static Output Feedback to Structured Robust Static Output Feedback: A Survey

    OpenAIRE

    Sadabadi , Mahdieh ,; Peaucelle , Dimitri

    2016-01-01

    This paper reviews the vast literature on static output feedback design for linear time-invariant systems including classical results and recent developments. In particular, we focus on static output feedback synthesis with performance specifications, structured static output feedback, and robustness. The paper provides a comprehensive review on existing design approaches including iterative linear matrix inequalities heuristics, linear matrix inequalities with rank constraints, methods with ...

  5. Success, Failure and Emotions: Examining the Relationship between Performance Feedback and Emotions in Diagnostic Reasoning

    Science.gov (United States)

    Jarrell, Amanda; Harley, Jason M.; Lajoie, Susanne; Naismith, Laura

    2017-01-01

    Students experience a variety of emotions following achievement outcomes which stand to influence how they learn and perform in academic settings. However, little is known about the link between student outcome emotions and dimensions of performance feedback in computer-based learning environments (CBLEs). Understanding the dynamics of this…

  6. Impact of quantitative feedback and benchmark selection on radiation use by cardiologists performing cardiac angiography

    International Nuclear Information System (INIS)

    Smith, I. R.; Cameron, J.; Brighouse, R. D.; Ryan, C. M.; Foster, K. A.; Rivers, J. T.

    2013-01-01

    Audit of and feedback on both group and individual data provided immediately after the point of care and compared with realistic benchmarks of excellence have been demonstrated to drive change. This study sought to evaluate the impact of immediate benchmarked quantitative case-based performance feedback on the clinical practice of cardiologists practicing at a private hospital in Brisbane, Australia. The participating cardiologists were assigned to one of two groups: Group 1 received patient and procedural details for review and Group 2 received Group 1 data plus detailed radiation data relating to the procedures and comparative benchmarks. In Group 2, Linear-by-Linear Association analysis suggests a link between change in radiation use and initial radiation dose category (p50.014) with only those initially 'challenged' by the benchmarks showing improvement. Those not 'challenged' by the benchmarks deteriorated in performance compared with those starting well below the benchmarks showing greatest increase in radiation use. Conversely, those blinded to their radiation use (Group 1) showed general improvement in radiation use throughout the study compared with those performing initially close to the benchmarks showing greatest improvement. This study shows that use of non-challenging benchmarks in case-based radiation risk feedback does not promote a reduction in radiation use; indeed, it may contribute to increased doses. Paradoxically, cardiologists who are aware of performance monitoring but blinded to individual case data appear to maintain, if not reduce, their radiation use. (authors)

  7. Self-Affirmation Theory and Performance Feedback: When Scoring High Makes You Feel Low.

    Science.gov (United States)

    Velez, John A; Hanus, Michael D

    2016-12-01

    Video games have a wide variety of benefits for players. The current study examines how video games can also increase players' willingness to internalize important but threatening self-information. Research suggests that negative information regarding a valued self-image evokes defensive strategies aimed at dismissing or discrediting the source of information. Self-Affirmation Theory proposes that affirming or bolstering an important self-image unrelated to the previous threat can be an effective strategy for reducing defensiveness. Participants in the current study completed a fictitious intelligence test and received negative or no feedback, followed by 15 minutes of video game play that resulted in positive or no feedback. Results suggest that participants who valued video game success as part of their identity exhibited less defensive strategies in the form of increased test credibility ratings and lower self-perceptions of intelligence. This suggests that performing well on a video game is an affirmational resource for players whose identities are contingent upon such success. However, results also indicate that players who did not value video game success but received positive video game feedback exhibited more defensive reactions to the negative intelligence test feedback. This suggests that while players who value video game success as part of their identity may reap benefits from video game play after a self-threat, those who do not value such success may experience more harmful effects.

  8. Postural sway and gaze can track the complex motion of a visual target.

    Directory of Open Access Journals (Sweden)

    Vassilia Hatzitaki

    Full Text Available Variability is an inherent and important feature of human movement. This variability has form exhibiting a chaotic structure. Visual feedback training using regular predictive visual target motions does not take into account this essential characteristic of the human movement, and may result in task specific learning and loss of visuo-motor adaptability. In this study, we asked how well healthy young adults can track visual target cues of varying degree of complexity during whole-body swaying in the Anterior-Posterior (AP and Medio-Lateral (ML direction. Participants were asked to track three visual target motions: a complex (Lorenz attractor, a noise (brown and a periodic (sine moving target while receiving online visual feedback about their performance. Postural sway, gaze and target motion were synchronously recorded and the degree of force-target and gaze-target coupling was quantified using spectral coherence and Cross-Approximate entropy. Analysis revealed that both force-target and gaze-target coupling was sensitive to the complexity of the visual stimuli motions. Postural sway showed a higher degree of coherence with the Lorenz attractor than the brown noise or sinusoidal stimulus motion. Similarly, gaze was more synchronous with the Lorenz attractor than the brown noise and sinusoidal stimulus motion. These results were similar regardless of whether tracking was performed in the AP or ML direction. Based on the theoretical model of optimal movement variability tracking of a complex signal may provide a better stimulus to improve visuo-motor adaptation and learning in postural control.

  9. Feedback stabilization initiative

    International Nuclear Information System (INIS)

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes

  10. Feedback stabilization initiative

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

  11. Vision-Based Haptic Feedback for Remote Micromanipulation in-SEM Environment

    Science.gov (United States)

    Bolopion, Aude; Dahmen, Christian; Stolle, Christian; Haliyo, Sinan; Régnier, Stéphane; Fatikow, Sergej

    2012-07-01

    This article presents an intuitive environment for remote micromanipulation composed of both haptic feedback and virtual reconstruction of the scene. To enable nonexpert users to perform complex teleoperated micromanipulation tasks, it is of utmost importance to provide them with information about the 3-D relative positions of the objects and the tools. Haptic feedback is an intuitive way to transmit such information. Since position sensors are not available at this scale, visual feedback is used to derive information about the scene. In this work, three different techniques are implemented, evaluated, and compared to derive the object positions from scanning electron microscope images. The modified correlation matching with generated template algorithm is accurate and provides reliable detection of objects. To track the tool, a marker-based approach is chosen since fast detection is required for stable haptic feedback. Information derived from these algorithms is used to propose an intuitive remote manipulation system that enables users situated in geographically distant sites to benefit from specific equipments, such as SEMs. Stability of the haptic feedback is ensured by the minimization of the delays, the computational efficiency of vision algorithms, and the proper tuning of the haptic coupling. Virtual guides are proposed to avoid any involuntary collisions between the tool and the objects. This approach is validated by a teleoperation involving melamine microspheres with a diameter of less than 2 μ m between Paris, France and Oldenburg, Germany.

  12. Framing of feedback impacts student’s satisfaction, self-efficacy and performance

    NARCIS (Netherlands)

    van de Ridder, J. M Monica; Peters, Claudia M M; Stokking, Karel M.; de Ru, J. Alexander; ten Cate, Olle Th J

    2014-01-01

    Feedback is considered important to acquire clinical skills. Research evidence shows that feedback does not always improve learning and its effects may be small. In many studies, a variety of variables involved in feedback provision may mask either one of their effects. E.g., there is reason to

  13. Effect of Performance Feedback on Perceived Knowledge and Likelihood to Pursue Continuing Education

    Science.gov (United States)

    Eberman, Lindsey E.; Tripp, Brady L.

    2011-01-01

    Context: For practicing health care professionals, waiting for a teachable moment to identify a gap in knowledge could prove critical. Other methods are needed to help health care professionals identify their knowledge gaps. Objective: To assess the effect of performance feedback on Athletic Trainers' (AT) perceived knowledge (PK) and likelihood…

  14. Feedback-linearization and feedback-feedforward decentralized control for multimachine power system

    Energy Technology Data Exchange (ETDEWEB)

    De Tuglie, Enrico [Dipartimento di Ingegneria dell' Ambiente, e per lo Sviluppo Sostenibile - DIASS, Politecnico di Bari, Viale del Turismo 8, 74100 Taranto (Italy); Iannone, Silvio Marcello; Torelli, Francesco [Dipartimento di Elettrotecnica, ed Elettronica - DEE, Politecnico di Bari, Via Re David 200, 70125 Bari (Italy)

    2008-03-15

    In this paper a decentralized nonlinear controller for large-scale power systems is investigated. The proposed controller design is based on the input-output feedback linearization methodology. In order to overcome computational difficulties in adopting such methodology, the overall interconnected nonlinear system, given as n-order, is analyzed as a cascade connection of an n{sub 1}-order nonlinear subsystem and an n{sub 2}-order linear subsystem. The controller design is obtained by applying input-output feedback linearization to the nonlinear subsystem and adopting a tracking control scheme, based on feedback-feedforward technique, for the linear subsystem. In the assumed system model, which is characterised by an interconnected structure between generating units, a decentralised adaptive controller is implemented by decentralizing these constraints. The use of a totally decentralised controller implies a system performance decay with respect to performance when the system is equipped with a centralised controller. Fortunately, the robustness of the proposed controller, based on input-output feedback procedure, guarantees good performance in terms of disturbance even when disturbances are caused by decentralization of interconnection constraints. Test results, provided on the IEEE 30 bus test system, demonstrate the effectiveness and practical applicability of proposed methodology. (author)

  15. Feedback System Theory

    Science.gov (United States)

    1978-11-01

    R 2. GOVT A $ SION NO. 3 RIEqLPýIVT’S.;TALOG NUMBER r/ 4. TITLE (and wbiFflT, -L M4 1 , FEEDBACK SYSTEM THEORY ~r Inter in- 6. PERFORMING ORG. REPORT...ANNUAL REPORT FEEDBACK SYSTEM THEORY AFOSR GRANT NO. 76-2946B Air Force Office of Scientific Research for year ending October 31, 1978 79 02 08 L|I...re less stringent than in other synthesis techniques which cannot handle significant parameter uncertainty. _I FEEDBACK SYSTEM THEORY 1. Introduction

  16. The effect of video-assisted oral feedback versus oral feedback on surgical communicative competences in undergraduate training.

    Science.gov (United States)

    Ruesseler, M; Sterz, J; Bender, B; Hoefer, S; Walcher, F

    2017-08-01

    Feedback can significantly improve future performance. Reviewing one's performance by video is discussed as useful adjunct to debriefing, particularly for non-technical skills. Communicative competencies are an essential part of daily clinical practice; thus should be taught and assessed during undergraduate training. The aim of this study was to compare the educational value of video-assisted feedback versus oral feedback in communicative competencies in the surgical context. Fourth-year medical students completed a 210-min training unit of 'taking patient's history and obtaining informed consents prior to surgery' using role plays. Oral feedback was received directly thereafter using agenda-led, outcome-based guidelines (ALOBA). In the study group, the role plays were video-taped and reviewed thereafter. Afterwards, students completed two OSCE stations, where they were assessed regarding their communicative competencies and the content of the clinical scenario. One-hundred students (49 receiving video-assisted feedback, 51 oral) participated in the study. Those receiving video-assisted feedback performed significantly better in overall score in both OSCE stations (p feedback offered a significant educational benefit over oral feedback alone during a simulated patient encounter in a surgical context.

  17. Feedback, Incentives and Peer Effects

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie Claire

    This paper experimentally investigates the impact of different pay and relative performance information policies on employee effort. We explore three information policies: No feedback, feedback given halfway through the production period, and continuously updated feedback about relative performan...... behind, and frontrunners do not slack off....

  18. The Two Visual Systems Hypothesis: new challenges and insights from visual form agnosic patient DF

    Directory of Open Access Journals (Sweden)

    Robert Leslie Whitwell

    2014-12-01

    Full Text Available Patient DF, who developed visual form agnosia following carbon monoxide poisoning, is still able to use vision to adjust the configuration of her grasping hand to the geometry of a goal object. This striking dissociation between perception and action in DF provided a key piece of evidence for the formulation of Goodale and Milner’s Two Visual Systems Hypothesis (TVSH. According to the TVSH, the ventral stream plays a critical role in constructing our visual percepts, whereas the dorsal stream mediates the visual control of action, such as visually guided grasping. In this review, we discuss recent studies of DF that provide new insights into the functional organization of the dorsal and ventral streams. We confirm recent evidence that DF has dorsal as well as ventral brain damage – and that her dorsal-stream lesions and surrounding atrophy have increased in size since her first published brain scan. We argue that the damage to DF’s dorsal stream explains her deficits in directing actions at targets in the periphery. We then focus on DF’s ability to accurately adjust her in-flight hand aperture to changes in the width of goal objects (grip scaling whose dimensions she cannot explicitly report. An examination of several studies of DF’s grip scaling under natural conditions reveals a modest though significant deficit. Importantly, however, she continues to show a robust dissociation between form vision for perception and form vision for action. We also review recent studies that explore the role of online visual feedback and terminal haptic feedback in the programming and control of her grasping. These studies make it clear that DF is no more reliant on visual or haptic feedback than are neurologically-intact individuals. In short, we argue that her ability to grasp objects depends on visual feedforward processing carried out by visuomotor networks in her dorsal stream that function in the much the same way as they do in neurologically

  19. Semantic congruency but not temporal synchrony enhances long-term memory performance for audio-visual scenes.

    Science.gov (United States)

    Meyerhoff, Hauke S; Huff, Markus

    2016-04-01

    Human long-term memory for visual objects and scenes is tremendous. Here, we test how auditory information contributes to long-term memory performance for realistic scenes. In a total of six experiments, we manipulated the presentation modality (auditory, visual, audio-visual) as well as semantic congruency and temporal synchrony between auditory and visual information of brief filmic clips. Our results show that audio-visual clips generally elicit more accurate memory performance than unimodal clips. This advantage even increases with congruent visual and auditory information. However, violations of audio-visual synchrony hardly have any influence on memory performance. Memory performance remained intact even with a sequential presentation of auditory and visual information, but finally declined when the matching tracks of one scene were presented separately with intervening tracks during learning. With respect to memory performance, our results therefore show that audio-visual integration is sensitive to semantic congruency but remarkably robust against asymmetries between different modalities.

  20. Negative Feedback for Small Capacitive Touchscreen Interfaces: A Usability Study for Data Entry Tasks.

    Science.gov (United States)

    Parikh, S P; Esposito, J M

    2012-01-01

    Touchscreen technology has become pervasive in the consumer product arena over the last decade, offering some distinct advantages such as software reconfigurable interfaces and the removal of space consuming mice and keyboards. However, there are significant drawbacks to these devices that have limited their adoption by some users. Most notably, standard touchscreens demand the user's visual attention and require them to look at the input device to avoid pressing the wrong button. This issue is particularly important for mobile, capacitive sensing, nonstylus devices, such as the iPhone where small button sizes can generate high error rates. While previous work has shown the benefits of augmenting such interfaces with audio or vibrotactile feedback, only positive feedback (confirmation of button presses) has been considered. In this paper, we present a simple prototype interface that provides negative vibrotactile feedback. By negative, we mean feedback is generated when an inactive or ambiguous part of the screen, such as the area between two buttons, is touched. First, we present a usability study comparing positive and negative vibrotactile feedback for a benchmark numerical data entry task. The difference in performance is not statistically significant, implying negative feedback provides comparable benefits. Next, based on the experimenter's observations and the users comments, we introduce a multimodal feedback strategy-combining complementary positive audio and negative vibrotactile signals. User tests on a text entry experiment show that, with multimodal feedback, users exhibit a (statistically significant) 24 percent reduction in corrective key presses, as compared to positive audio feedback alone. Exit survey comments indicate that users favor multimodal feedback.

  1. Functionality and Performance Visualization of the Distributed High Quality Volume Renderer (HVR)

    KAUST Repository

    Shaheen, Sara

    2012-07-01

    Volume rendering systems are designed to provide means to enable scientists and a variety of experts to interactively explore volume data through 3D views of the volume. However, volume rendering techniques are computationally intensive tasks. Moreover, parallel distributed volume rendering systems and multi-threading architectures were suggested as natural solutions to provide an acceptable volume rendering performance for very large volume data sizes, such as Electron Microscopy data (EM). This in turn adds another level of complexity when developing and manipulating volume rendering systems. Given that distributed parallel volume rendering systems are among the most complex systems to develop, trace and debug, it is obvious that traditional debugging tools do not provide enough support. As a consequence, there is a great demand to provide tools that are able to facilitate the manipulation of such systems. This can be achieved by utilizing the power of compute graphics in designing visual representations that reflect how the system works and that visualize the current performance state of the system.The work presented is categorized within the field of software Visualization, where Visualization is used to serve visualizing and understanding various software. In this thesis, a number of visual representations that reflect a number of functionality and performance aspects of the distributed HVR, a high quality volume renderer system that uses various techniques to visualize large volume sizes interactively. This work is provided to visualize different stages of the parallel volume rendering pipeline of HVR. This is along with means of performance analysis through a number of flexible and dynamic visualizations that reflect the current state of the system and enables manipulation of them at runtime. Those visualization are aimed to facilitate debugging, understanding and analyzing the distributed HVR.

  2. Technologies for learner-centered feedback

    Directory of Open Access Journals (Sweden)

    Jane Costello

    2013-09-01

    Full Text Available As the number, type, and use of technologies to support learning increases, so do the opportunities for using these technologies for feedback. Learner-centered feedback is a core to the teaching-learning process. It is related to assessment in describing how learners perform in their learning, their gain in knowledge, skills, and attitudes. Feedback, types of feedback, guidelines for effective learner-centered feedback, and feedback’s relationship to assessment are presented. Methods of providing feedback, for example, automated, audio scribe pens, digital audio, etc., and the related technologies are described. Technologies that allow instructors to make informed decisions about the use of various methods for feedback are discussed.

  3. How visual search relates to visual diagnostic performance: a narrative systematic review of eye-tracking research in radiology.

    Science.gov (United States)

    van der Gijp, A; Ravesloot, C J; Jarodzka, H; van der Schaaf, M F; van der Schaaf, I C; van Schaik, J P J; Ten Cate, Th J

    2017-08-01

    Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review of eye-tracking literature in the radiology domain aims to identify visual search patterns associated with high perceptual performance. Databases PubMed, EMBASE, ERIC, PsycINFO, Scopus and Web of Science were searched using 'visual perception' OR 'eye tracking' AND 'radiology' and synonyms. Two authors independently screened search results and included eye tracking studies concerning visual skills in radiology published between January 1, 1994 and July 31, 2015. Two authors independently assessed study quality with the Medical Education Research Study Quality Instrument, and extracted study data with respect to design, participant and task characteristics, and variables. A thematic analysis was conducted to extract and arrange study results, and a textual narrative synthesis was applied for data integration and interpretation. The search resulted in 22 relevant full-text articles. Thematic analysis resulted in six themes that informed the relation between visual search and level of expertise: (1) time on task, (2) eye movement characteristics of experts, (3) differences in visual attention, (4) visual search patterns, (5) search patterns in cross sectional stack imaging, and (6) teaching visual search strategies. Expert search was found to be characterized by a global-focal search pattern, which represents an initial global impression, followed by a detailed, focal search-to-find mode. Specific task-related search patterns, like drilling through CT scans and systematic search in chest X-rays, were found to be related to high expert levels. One study investigated teaching of visual search strategies, and did not find a significant effect on perceptual performance. Eye

  4. Effect of feedback on delaying deterioration in quality of compressions during 2 minutes of continuous chest compressions

    DEFF Research Database (Denmark)

    Lyngeraa, Tobias S; Hjortrup, Peter Buhl; Wulff, Nille B

    2012-01-01

    delays deterioration of quality of compressions. METHODS: Participants attending a national one-day conference on cardiac arrest and CPR in Denmark were randomized to perform single-rescuer BLS with (n = 26) or without verbal and visual feedback (n = 28) on a manikin using a ZOLL AED plus. Data were...... analyzed using Rescuenet Code Review. Blinding of participants was not possible, but allocation concealment was performed. Primary outcome was the proportion of delivered compressions within target depth compared over a 2-minute period within the groups and between the groups. Secondary outcome...... was the proportion of delivered compressions within target rate compared over a 2-minute period within the groups and between the groups. Performance variables for 30-second intervals were analyzed and compared. RESULTS: 24 (92%) and 23 (82%) had CPR experience in the group with and without feedback respectively. 14...

  5. Multisource feedback to graduate nurses: a multimethod study.

    Science.gov (United States)

    McPhee, Samantha; Phillips, Nicole M; Ockerby, Cherene; Hutchinson, Alison M

    2017-11-01

    (1) To explore graduate nurses' perceptions of the influence of multisource feedback on their performance and (2) to explore perceptions of Clinical Nurse Educators involved in providing feedback regarding feasibility and benefit of the approach. Graduate registered nurses are expected to provide high-quality care for patients in demanding and unpredictable clinical environments. Receiving feedback is essential to their development. Performance appraisals are a common method used to provide feedback and typically involve a single source of feedback. Alternatively, multisource feedback allows the learner to gain insight into performance from a variety of perspectives. This study explores multisource feedback in an Australian setting within the graduate nurse context. Multimethod study. Eleven graduates were given structured performance feedback from four raters: Nurse Unit Manager, Clinical Nurse Educator, preceptor and a self-appraisal. Thirteen graduates received standard single-rater appraisals. Data regarding perceptions of feedback for both groups were obtained using a questionnaire. Semistructured interviews were conducted with nurses who received multisource feedback and the educators. In total, 94% (n = 15) of survey respondents perceived feedback was important during the graduate year. Four themes emerged from interviews: informal feedback, appropriateness of raters, elements of delivery and creating an appraisal process that is 'more real'. Multisource feedback was perceived as more beneficial compared to single-rater feedback. Educators saw value in multisource feedback; however, perceived barriers were engaging raters and collating feedback. Some evidence exists to indicate that feedback from multiple sources is valued by graduates. Further research in a larger sample and with more experienced nurses is required. Evidence resulting from this study indicates that multisource feedback is valued by both graduates and educators and informs graduates

  6. Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback.

    Science.gov (United States)

    Kurzynski, Marek; Jaskolska, Anna; Marusiak, Jaroslaw; Wolczowski, Andrzej; Bierut, Przemyslaw; Szumowski, Lukasz; Witkowski, Jerzy; Kisiel-Sajewicz, Katarzyna

    2017-08-01

    One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. RF feedback for KEKB

    Energy Technology Data Exchange (ETDEWEB)

    Ezura, Eizi; Yoshimoto, Shin-ichi; Akai, Kazunori [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    This paper describes the present status of the RF feedback development for the KEK B-Factory (KEKB). A preliminary experiment concerning the RF feedback using a parallel comb-filter was performed through a choke-mode cavity and a klystron. The RF feedback has been tested using the beam of the TRISTAN Main Ring, and has proved to be effective in damping the beam instability. (author)

  8. Haptic Feedback for Enhancing Realism of Walking Simulations

    DEFF Research Database (Denmark)

    Turchet, Luca; Burelli, Paolo; Serafin, Stefania

    2013-01-01

    system. While during the use of the interactive system subjects physically walked, during the use of the non-interactive system the locomotion was simulated while subjects were sitting on a chair. In both the configurations subjects were exposed to auditory and audio-visual stimuli presented...... with and without the haptic feedback. Results of the experiments provide a clear preference towards the simulations enhanced with haptic feedback showing that the haptic channel can lead to more realistic experiences in both interactive and non-interactive configurations. The majority of subjects clearly...... appreciated the added feedback. However, some subjects found the added feedback disturbing and annoying. This might be due on one hand to the limits of the haptic simulation and on the other hand to the different individual desire to be involved in the simulations. Our findings can be applied to the context...

  9. Feedback enhances feedforward figure-ground segmentation by changing firing mode.

    Science.gov (United States)

    Supèr, Hans; Romeo, August

    2011-01-01

    In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforward spiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz) bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic) spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses with the responses to a homogenous texture. We propose that feedback controls figure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons.

  10. Feedback enhances feedforward figure-ground segmentation by changing firing mode.

    Directory of Open Access Journals (Sweden)

    Hans Supèr

    Full Text Available In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforward spiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses with the responses to a homogenous texture. We propose that feedback controls figure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons.

  11. Feedback Enhances Feedforward Figure-Ground Segmentation by Changing Firing Mode

    Science.gov (United States)

    Supèr, Hans; Romeo, August

    2011-01-01

    In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforwardspiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz) bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic) spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses withthe responses to a homogenous texture. We propose that feedback controlsfigure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons. PMID:21738747

  12. Are the senses enough for sense? Early high-level feedback shapes our comprehension of multisensory objects

    Directory of Open Access Journals (Sweden)

    Lorina eNaci

    2012-09-01

    Full Text Available A key question in cognitive neuroscience is how the brain combines low-level features processed in remote sensory cortices to represent meaningful multisensory objects in our everyday environment. Models of visual object processing typically assume a feedforward cascade through the hierarchically organized ventral stream. We contrasted this feedforward view with an alternate hypothesis in which object processing is viewed as an interactive, feedforward and feedback process. We found that higher-order regions in anterior temporal and inferior prefrontal cortex performed audio-visual integration 100ms earlier than a sensory-driven region in the posterior occipital cortex, and were modulated by semantic variables (congruency, from as early as 50-100ms. We propose that the brain represents familiar and complex multisensory objects through early interactivity between higher-order and sensory-driven regions. This interactivity may underpin the enhanced behavioural performance reported for semantically congruent audio-visual objects.

  13. Visual search performance among persons with schizophrenia as a function of target eccentricity.

    Science.gov (United States)

    Elahipanah, Ava; Christensen, Bruce K; Reingold, Eyal M

    2010-03-01

    The current study investigated one possible mechanism of impaired visual attention among patients with schizophrenia: a reduced visual span. Visual span is the region of the visual field from which one can extract information during a single eye fixation. This study hypothesized that schizophrenia-related visual search impairment is mediated, in part, by a smaller visual span. To test this hypothesis, 23 patients with schizophrenia and 22 healthy controls completed a visual search task where the target was pseudorandomly presented at different distances from the center of the display. Response times were analyzed as a function of search condition (feature vs. conjunctive), display size, and target eccentricity. Consistent with previous reports, patient search times were more adversely affected as the number of search items increased in the conjunctive search condition. It was important however, that patients' conjunctive search times were also impacted to a greater degree by target eccentricity. Moreover, a significant impairment in patients' visual search performance was only evident when targets were more eccentric and their performance was more similar to healthy controls when the target was located closer to the center of the search display. These results support the hypothesis that a narrower visual span may underlie impaired visual search performance among patients with schizophrenia. Copyright 2010 APA, all rights reserved

  14. Evaluating the Performance of a Visually Guided Hearing Aid Using a Dynamic Auditory-Visual Word Congruence Task.

    Science.gov (United States)

    Roverud, Elin; Best, Virginia; Mason, Christine R; Streeter, Timothy; Kidd, Gerald

    2017-12-15

    The "visually guided hearing aid" (VGHA), consisting of a beamforming microphone array steered by eye gaze, is an experimental device being tested for effectiveness in laboratory settings. Previous studies have found that beamforming without visual steering can provide significant benefits (relative to natural binaural listening) for speech identification in spatialized speech or noise maskers when sound sources are fixed in location. The aim of the present study was to evaluate the performance of the VGHA in listening conditions in which target speech could switch locations unpredictably, requiring visual steering of the beamforming. To address this aim, the present study tested an experimental simulation of the VGHA in a newly designed dynamic auditory-visual word congruence task. Ten young normal-hearing (NH) and 11 young hearing-impaired (HI) adults participated. On each trial, three simultaneous spoken words were presented from three source positions (-30, 0, and 30 azimuth). An auditory-visual word congruence task was used in which participants indicated whether there was a match between the word printed on a screen at a location corresponding to the target source and the spoken target word presented acoustically from that location. Performance was compared for a natural binaural condition (stimuli presented using impulse responses measured on KEMAR), a simulated VGHA condition (BEAM), and a hybrid condition that combined lowpass-filtered KEMAR and highpass-filtered BEAM information (BEAMAR). In some blocks, the target remained fixed at one location across trials, and in other blocks, the target could transition in location between one trial and the next with a fixed but low probability. Large individual variability in performance was observed. There were significant benefits for the hybrid BEAMAR condition relative to the KEMAR condition on average for both NH and HI groups when the targets were fixed. Although not apparent in the averaged data, some

  15. Fuzzy Adaptive Output Feedback Control of Uncertain Nonlinear Systems With Prescribed Performance.

    Science.gov (United States)

    Zhang, Jin-Xi; Yang, Guang-Hong

    2018-05-01

    This paper investigates the tracking control problem for a family of strict-feedback systems in the presence of unknown nonlinearities and immeasurable system states. A low-complexity adaptive fuzzy output feedback control scheme is proposed, based on a backstepping method. In the control design, a fuzzy adaptive state observer is first employed to estimate the unmeasured states. Then, a novel error transformation approach together with a new modification mechanism is introduced to guarantee the finite-time convergence of the output error to a predefined region and ensure the closed-loop stability. Compared with the existing methods, the main advantages of our approach are that: 1) without using extra command filters or auxiliary dynamic surface control techniques, the problem of explosion of complexity can still be addressed and 2) the design procedures are independent of the initial conditions. Finally, two practical examples are performed to further illustrate the above theoretic findings.

  16. Power profiles and short-term visual performance of soft contact lenses.

    Science.gov (United States)

    Papas, Eric; Dahms, Anne; Carnt, Nicole; Tahhan, Nina; Ehrmann, Klaus

    2009-04-01

    To investigate the manner in which contemporary soft contact lenses differ in the distribution of optical power within their optic zones and establish if these variations affect the vision of wearers or the prescribing procedure for back vertex power (BVP). By using a Visionix VC 2001 contact lens power analyzer, power profiles were measured across the optic zones of the following contemporary contact lenses ACUVUE 2, ACUVUE ADVANCE, O2OPTIX, NIGHT & DAY and PureVision. Single BVP measures were obtained using a Nikon projection lensometer. Visual performance was assessed in 28 masked subjects who wore each lens type in random order. Measurements taken were high and low contrast visual acuity in normal illumination (250 Cd/m), high contrast acuity in reduced illumination (5 Cd/m), subjective visual quality using a numerical rating scale, and visual satisfaction rating using a Likert scale. Marked differences in the distribution of optical power across the optic zone were evident among the lens types. No significant differences were found for any of the visual performance variables (p > 0.05, analysis of variance with repeated measures and Friedman test). Variations in power profile between contemporary soft lens types exist but do not, in general, result in measurable visual performance differences in the short term, nor do they substantially influence the BVP required for optimal correction.

  17. Comparison between hybrid feedforward-feedback, feedforward, and feedback structures for active noise control of fMRI noise.

    Science.gov (United States)

    Reddy, Rajiv M; Panahi, Issa M S

    2008-01-01

    The performance of FIR feedforward, IIR feedforward, FIR feedback, hybrid FIR feedforward--FIR feedback, and hybrid IIR feedforward - FIR feedback structures for active noise control (ANC) are compared for an fMRI noise application. The filtered-input normalized least squares (FxNLMS) algorithm is used to update the coefficients of the adaptive filters in all these structures. Realistic primary and secondary paths of an fMRI bore are used by estimating them on a half cylindrical acrylic bore of 0.76 m (D)x1.52 m (L). Detailed results of the performance of the ANC system are presented in the paper for each of these structures. We find that the IIR feedforward structure produces most of the performance improvement in the hybrid IIR feedforward - FIR feedback structure and adding the feedback structure becomes almost redundant in the case of fMRI noise.

  18. Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features

    Directory of Open Access Journals (Sweden)

    Chang-Hee Han

    2016-01-01

    Full Text Available It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

  19. Evolution of attention mechanisms for early visual processing

    Science.gov (United States)

    Müller, Thomas; Knoll, Alois

    2011-03-01

    Early visual processing as a method to speed up computations on visual input data has long been discussed in the computer vision community. The general target of a such approaches is to filter nonrelevant information from the costly higher-level visual processing algorithms. By insertion of this additional filter layer the overall approach can be speeded up without actually changing the visual processing methodology. Being inspired by the layered architecture of the human visual processing apparatus, several approaches for early visual processing have been recently proposed. Most promising in this field is the extraction of a saliency map to determine regions of current attention in the visual field. Such saliency can be computed in a bottom-up manner, i.e. the theory claims that static regions of attention emerge from a certain color footprint, and dynamic regions of attention emerge from connected blobs of textures moving in a uniform way in the visual field. Top-down saliency effects are either unconscious through inherent mechanisms like inhibition-of-return, i.e. within a period of time the attention level paid to a certain region automatically decreases if the properties of that region do not change, or volitional through cognitive feedback, e.g. if an object moves consistently in the visual field. These bottom-up and top-down saliency effects have been implemented and evaluated in a previous computer vision system for the project JAST. In this paper an extension applying evolutionary processes is proposed. The prior vision system utilized multiple threads to analyze the regions of attention delivered from the early processing mechanism. Here, in addition, multiple saliency units are used to produce these regions of attention. All of these saliency units have different parameter-sets. The idea is to let the population of saliency units create regions of attention, then evaluate the results with cognitive feedback and finally apply the genetic mechanism

  20. Real-time feedback enhances forward propulsion during walking in old adults.

    Science.gov (United States)

    Franz, Jason R; Maletis, Michela; Kram, Rodger

    2014-01-01

    Reduced propulsive function during the push-off phase of walking plays a central role in the deterioration of walking ability with age. We used real-time propulsive feedback to test the hypothesis that old adults have an underutilized propulsive reserve available during walking. 8 old adults (mean [SD], age: 72.1 [3.9] years) and 11 young adults (age: 21.0 [1.5] years) participated. For our primary aim, old subjects walked: 1) normally, 2) with visual feedback of their peak propulsive ground reaction forces, and 3) with visual feedback of their medial gastrocnemius electromyographic activity during push-off. We asked those subjects to match a target set to 20% and 40% greater propulsive force or push-off muscle activity than normal walking. We tested young subjects walking normally only to provide reference ground reaction force values. Walking normally, old adults exerted 12.5% smaller peak propulsive forces than young adults (Ppush-off muscle activities when we provided propulsive feedback. Most notably, force feedback elicited propulsive forces that were equal to or 10.5% greater than those of young adults (+20% target, P=0.87; +40% target, P=0.02). With electromyographic feedback, old adults significantly increased their push-off muscle activities but without increasing their propulsive forces. Old adults with propulsive deficits have a considerable and underutilized propulsive reserve available during level walking. Further, real-time propulsive feedback represents a promising therapeutic strategy to improve the forward propulsion of old adults and thus maintain their walking ability and independence. © 2013.

  1. Feedback Systems for Linear Colliders

    International Nuclear Information System (INIS)

    1999-01-01

    Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an integral part of the design. Feedback requirements for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at high bandwidth and fast response. To correct for the motion of individual bunches within a train, both feedforward and feedback systems are planned. SLC experience has shown that feedback systems are an invaluable operational tool for decoupling systems, allowing precision tuning, and providing pulse-to-pulse diagnostics. Feedback systems for the NLC will incorporate the key SLC features and the benefits of advancing technologies

  2. Force control in the absence of visual and tactile feedback

    NARCIS (Netherlands)

    Mugge, W.; Abbink, D.A.; Schouten, Alfred Christiaan; van der Helm, F.C.T.; Arendzen, J.H.; Meskers, C.G.M.

    2013-01-01

    Motor control tasks like stance or object handling require sensory feedback from proprioception, vision and touch. The distinction between tactile and proprioceptive sensors is not frequently made in dynamic motor control tasks, and if so, mostly based on signal latency. We previously found that

  3. Perception of CPR quality: Influence of CPR feedback, Just-in-Time CPR training and provider role.

    Science.gov (United States)

    Cheng, Adam; Overly, Frank; Kessler, David; Nadkarni, Vinay M; Lin, Yiqun; Doan, Quynh; Duff, Jonathan P; Tofil, Nancy M; Bhanji, Farhan; Adler, Mark; Charnovich, Alex; Hunt, Elizabeth A; Brown, Linda L

    2015-02-01

    Many healthcare providers rely on visual perception to guide cardiopulmonary resuscitation (CPR), but little is known about the accuracy of provider perceptions of CPR quality. We aimed to describe the difference between perceived versus measured CPR quality, and to determine the impact of provider role, real-time visual CPR feedback and Just-in-Time (JIT) CPR training on provider perceptions. We conducted secondary analyses of data collected from a prospective, multicenter, randomized trial of 324 healthcare providers who participated in a simulated cardiac arrest scenario between July 2012 and April 2014. Participants were randomized to one of four permutations of: JIT CPR training and real-time visual CPR feedback. We calculated the difference between perceived and measured quality of CPR and reported the proportion of subjects accurately estimating the quality of CPR within each study arm. Participants overestimated achieving adequate chest compression depth (mean difference range: 16.1-60.6%) and rate (range: 0.2-51%), and underestimated chest compression fraction (0.2-2.9%) across all arms. Compared to no intervention, the use of real-time feedback and JIT CPR training (alone or in combination) improved perception of depth (pCPR quality was poor for chest compression depth (0-13%), rate (5-46%) and chest compression fraction (60-63%). Perception of depth is more accurate in CPR providers versus team leaders (27.8% vs. 7.4%; p=0.043) when using real-time feedback. Healthcare providers' visual perception of CPR quality is poor. Perceptions of CPR depth are improved by using real-time visual feedback and with prior JIT CPR training. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals.

    Science.gov (United States)

    van Boxtel, M P; ten Tusscher, M P; Metsemakers, J F; Willems, B; Jolles, J

    2001-10-01

    It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

  5. A User Study of Visualization Effectiveness Using EEG and Cognitive Load

    KAUST Repository

    Anderson, E. W.; Potter, K. C.; Matzen, L. E.; Shepherd, J. F.; Preston, G. A.; Silva, C. T.

    2011-01-01

    Effectively evaluating visualization techniques is a difficult task often assessed through feedback from user studies and expert evaluations. This work presents an alternative approach to visualization evaluation in which brain activity is passively recorded using electroencephalography (EEG). These measurements are used to compare different visualization techniques in terms of the burden they place on a viewer's cognitive resources. In this paper, EEG signals and response times are recorded while users interpret different representations of data distributions. This information is processed to provide insight into the cognitive load imposed on the viewer. This paper describes the design of the user study performed, the extraction of cognitive load measures from EEG data, and how those measures are used to quantitatively evaluate the effectiveness of visualizations. © 2011 The Author(s).

  6. A User Study of Visualization Effectiveness Using EEG and Cognitive Load

    KAUST Repository

    Anderson, E. W.

    2011-06-01

    Effectively evaluating visualization techniques is a difficult task often assessed through feedback from user studies and expert evaluations. This work presents an alternative approach to visualization evaluation in which brain activity is passively recorded using electroencephalography (EEG). These measurements are used to compare different visualization techniques in terms of the burden they place on a viewer\\'s cognitive resources. In this paper, EEG signals and response times are recorded while users interpret different representations of data distributions. This information is processed to provide insight into the cognitive load imposed on the viewer. This paper describes the design of the user study performed, the extraction of cognitive load measures from EEG data, and how those measures are used to quantitatively evaluate the effectiveness of visualizations. © 2011 The Author(s).

  7. Selective and divided attention modulates auditory-vocal integration in the processing of pitch feedback errors.

    Science.gov (United States)

    Liu, Ying; Hu, Huijing; Jones, Jeffery A; Guo, Zhiqiang; Li, Weifeng; Chen, Xi; Liu, Peng; Liu, Hanjun

    2015-08-01

    Speakers rapidly adjust their ongoing vocal productions to compensate for errors they hear in their auditory feedback. It is currently unclear what role attention plays in these vocal compensations. This event-related potential (ERP) study examined the influence of selective and divided attention on the vocal and cortical responses to pitch errors heard in auditory feedback regarding ongoing vocalisations. During the production of a sustained vowel, participants briefly heard their vocal pitch shifted up two semitones while they actively attended to auditory or visual events (selective attention), or both auditory and visual events (divided attention), or were not told to attend to either modality (control condition). The behavioral results showed that attending to the pitch perturbations elicited larger vocal compensations than attending to the visual stimuli. Moreover, ERPs were likewise sensitive to the attentional manipulations: P2 responses to pitch perturbations were larger when participants attended to the auditory stimuli compared to when they attended to the visual stimuli, and compared to when they were not explicitly told to attend to either the visual or auditory stimuli. By contrast, dividing attention between the auditory and visual modalities caused suppressed P2 responses relative to all the other conditions and caused enhanced N1 responses relative to the control condition. These findings provide strong evidence for the influence of attention on the mechanisms underlying the auditory-vocal integration in the processing of pitch feedback errors. In addition, selective attention and divided attention appear to modulate the neurobehavioral processing of pitch feedback errors in different ways. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

    Science.gov (United States)

    Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

    2014-09-01

    In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

  9. Visual Motor and Perceptual Task Performance in Astigmatic Students

    Directory of Open Access Journals (Sweden)

    Erin M. Harvey

    2017-01-01

    Full Text Available Purpose. To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. Methods. Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D or bilateral astigmatism group (right and left eye ≥ 1.00 D based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI and Visual Perception (VMIp. Astigmats were randomly assigned to testing with/without correction and control group was tested uncorrected. Analyses compared VMI and VMIp scores for corrected and uncorrected astigmats to the control group. Results. The sample included 333 students (control group 170, astigmats tested with correction 75, and astigmats tested uncorrected 88. Mean VMI score in corrected astigmats did not differ from the control group (p=0.829. Uncorrected astigmats had lower VMI scores than the control group (p=0.038 and corrected astigmats (p=0.007. Mean VMIp scores for uncorrected (p=0.209 and corrected astigmats (p=0.124 did not differ from the control group. Uncorrected astigmats had lower mean scores than the corrected astigmats (p=0.003. Conclusions. Uncorrected astigmatism influences visual motor and perceptual task performance. Previously spectacle treated astigmats do not show developmental deficits on visual motor or perceptual tasks when tested with correction.

  10. Funny money: the attentional role of monetary feedback detached from expected value.

    Science.gov (United States)

    Roper, Zachary J J; Vecera, Shaun P

    2016-10-01

    Stimuli associated with monetary reward can become powerful cues that effectively capture visual attention. We examined whether such value-driven attentional capture can be induced with monetary feedback in the absence of an expected cash payout. To this end, we implemented images of U.S. dollar bills as reward feedback. Participants knew in advance that they would not receive any money based on their performance. Our reward stimuli-$5 and $20 bill images-were thus dissociated from any practical utility. Strikingly, we observed a reliable attentional capture effect for the mere images of bills. Moreover, this finding generalized to Monopoly money. In two control experiments, we found no evidence in favor of nominal or symbolic monetary value. Hence, we claim that bill images are special monetary representations, such that there are strong associations between the defining visual features of bills and reward, probably due to a lifelong learning history. Together, we show that the motivation to earn cash plays a minor role when it comes to monetary rewards, while bill-defining visual features seem to be sufficient. These findings have the potential to influence human factor applications, such as gamification, and can be extended to novel value systems, such as the electronic cash Bitcoin being developed for use in mobile banking. Finally, our procedure represents a proof of concept on how images of money can be used to conserve expenditures in the experimental context.

  11. Feedback systems for linear colliders

    CERN Document Server

    Hendrickson, L; Himel, Thomas M; Minty, Michiko G; Phinney, N; Raimondi, Pantaleo; Raubenheimer, T O; Shoaee, H; Tenenbaum, P G

    1999-01-01

    Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an intregal part of the design. Feedback requiremetns for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at hi...

  12. Attention to Color Sharpens Neural Population Tuning via Feedback Processing in the Human Visual Cortex Hierarchy.

    Science.gov (United States)

    Bartsch, Mandy V; Loewe, Kristian; Merkel, Christian; Heinze, Hans-Jochen; Schoenfeld, Mircea A; Tsotsos, John K; Hopf, Jens-Max

    2017-10-25

    Attention can facilitate the selection of elementary object features such as color, orientation, or motion. This is referred to as feature-based attention and it is commonly attributed to a modulation of the gain and tuning of feature-selective units in visual cortex. Although gain mechanisms are well characterized, little is known about the cortical processes underlying the sharpening of feature selectivity. Here, we show with high-resolution magnetoencephalography in human observers (men and women) that sharpened selectivity for a particular color arises from feedback processing in the human visual cortex hierarchy. To assess color selectivity, we analyze the response to a color probe that varies in color distance from an attended color target. We find that attention causes an initial gain enhancement in anterior ventral extrastriate cortex that is coarsely selective for the target color and transitions within ∼100 ms into a sharper tuned profile in more posterior ventral occipital cortex. We conclude that attention sharpens selectivity over time by attenuating the response at lower levels of the cortical hierarchy to color values neighboring the target in color space. These observations support computational models proposing that attention tunes feature selectivity in visual cortex through backward-propagating attenuation of units less tuned to the target. SIGNIFICANCE STATEMENT Whether searching for your car, a particular item of clothing, or just obeying traffic lights, in everyday life, we must select items based on color. But how does attention allow us to select a specific color? Here, we use high spatiotemporal resolution neuromagnetic recordings to examine how color selectivity emerges in the human brain. We find that color selectivity evolves as a coarse to fine process from higher to lower levels within the visual cortex hierarchy. Our observations support computational models proposing that feature selectivity increases over time by attenuating the

  13. Visually Evoked Visual-Auditory Changes Associated with Auditory Performance in Children with Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Maojin Liang

    2017-10-01

    Full Text Available Activation of the auditory cortex by visual stimuli has been reported in deaf children. In cochlear implant (CI patients, a residual, more intense cortical activation in the frontotemporal areas in response to photo stimuli was found to be positively associated with poor auditory performance. Our study aimed to investigate the mechanism by which visual processing in CI users activates the auditory-associated cortex during the period after cochlear implantation as well as its relation to CI outcomes. Twenty prelingually deaf children with CI were recruited. Ten children were good CI performers (GCP and ten were poor (PCP. Ten age- and sex- matched normal-hearing children were recruited as controls, and visual evoked potentials (VEPs were recorded. The characteristics of the right frontotemporal N1 component were analyzed. In the prelingually deaf children, higher N1 amplitude was observed compared to normal controls. While the GCP group showed significant decreases in N1 amplitude, and source analysis showed the most significant decrease in brain activity was observed in the primary visual cortex (PVC, with a downward trend in the primary auditory cortex (PAC activity, but these did not occur in the PCP group. Meanwhile, higher PVC activation (comparing to controls before CI use (0M and a significant decrease in source energy after CI use were found to be related to good CI outcomes. In the GCP group, source energy decreased in the visual-auditory cortex with CI use. However, no significant cerebral hemispheric dominance was found. We supposed that intra- or cross-modal reorganization and higher PVC activation in prelingually deaf children may reflect a stronger potential ability of cortical plasticity. Brain activity evolution appears to be related to CI auditory outcomes.

  14. Visually Evoked Visual-Auditory Changes Associated with Auditory Performance in Children with Cochlear Implants.

    Science.gov (United States)

    Liang, Maojin; Zhang, Junpeng; Liu, Jiahao; Chen, Yuebo; Cai, Yuexin; Wang, Xianjun; Wang, Junbo; Zhang, Xueyuan; Chen, Suijun; Li, Xianghui; Chen, Ling; Zheng, Yiqing

    2017-01-01

    Activation of the auditory cortex by visual stimuli has been reported in deaf children. In cochlear implant (CI) patients, a residual, more intense cortical activation in the frontotemporal areas in response to photo stimuli was found to be positively associated with poor auditory performance. Our study aimed to investigate the mechanism by which visual processing in CI users activates the auditory-associated cortex during the period after cochlear implantation as well as its relation to CI outcomes. Twenty prelingually deaf children with CI were recruited. Ten children were good CI performers (GCP) and ten were poor (PCP). Ten age- and sex- matched normal-hearing children were recruited as controls, and visual evoked potentials (VEPs) were recorded. The characteristics of the right frontotemporal N1 component were analyzed. In the prelingually deaf children, higher N1 amplitude was observed compared to normal controls. While the GCP group showed significant decreases in N1 amplitude, and source analysis showed the most significant decrease in brain activity was observed in the primary visual cortex (PVC), with a downward trend in the primary auditory cortex (PAC) activity, but these did not occur in the PCP group. Meanwhile, higher PVC activation (comparing to controls) before CI use (0M) and a significant decrease in source energy after CI use were found to be related to good CI outcomes. In the GCP group, source energy decreased in the visual-auditory cortex with CI use. However, no significant cerebral hemispheric dominance was found. We supposed that intra- or cross-modal reorganization and higher PVC activation in prelingually deaf children may reflect a stronger potential ability of cortical plasticity. Brain activity evolution appears to be related to CI auditory outcomes.

  15. Haptic and Visual feedback in 3D Audio Mixing Interfaces

    DEFF Research Database (Denmark)

    Gelineck, Steven; Overholt, Daniel

    2015-01-01

    This paper describes the implementation and informal evaluation of a user interface that explores haptic feedback for 3D audio mixing. The implementation compares different approaches using either the LEAP Motion for mid-air hand gesture control, or the Novint Falcon for active haptic feed- back...

  16. Leadership in Libraries--Feedback as Communication.

    Science.gov (United States)

    Wright, Dianne H.

    This paper focuses on the role of feedback in effective communication and ways in which feedback can assist library managers at all levels in performing their role as leaders. The various kinds and sources of feedback are discussed, and the relationship between feedback and goal setting are considered, as well as the effects of goal setting and…

  17. Altering sensorimotor feedback disrupts visual discrimination of facial expressions.

    Science.gov (United States)

    Wood, Adrienne; Lupyan, Gary; Sherrin, Steven; Niedenthal, Paula

    2016-08-01

    Looking at another person's facial expression of emotion can trigger the same neural processes involved in producing the expression, and such responses play a functional role in emotion recognition. Disrupting individuals' facial action, for example, interferes with verbal emotion recognition tasks. We tested the hypothesis that facial responses also play a functional role in the perceptual processing of emotional expressions. We altered the facial action of participants with a gel facemask while they performed a task that involved distinguishing target expressions from highly similar distractors. Relative to control participants, participants in the facemask condition demonstrated inferior perceptual discrimination of facial expressions, but not of nonface stimuli. The findings suggest that somatosensory/motor processes involving the face contribute to the visual perceptual-and not just conceptual-processing of facial expressions. More broadly, our study contributes to growing evidence for the fundamentally interactive nature of the perceptual inputs from different sensory modalities.

  18. Multi-bunch Feedback Systems

    OpenAIRE

    Lonza, M.; Schmickler, H.

    2016-01-01

    Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides importa...

  19. Impact of low vision rehabilitation on functional vision performance of children with visual impairment.

    Science.gov (United States)

    Ganesh, Suma; Sethi, Sumita; Srivastav, Sonia; Chaudhary, Amrita; Arora, Priyanka

    2013-09-01

    To evaluate the impact of low vision rehabilitation on functional vision of children with visual impairment. The LV Prasad-Functional Vision Questionnaire, designed specifically to measure functional performance of visually impaired children of developing countries, was used to assess the level of difficulty in performing various tasks pre and post visual rehabilitation in children with documented visual impairment. Chi-square test was used to assess the impact of rehabilitation intervention on functional vision performance; a P visual acuity prior to the introduction of low vision devices (LVDs) was 0.90 ± 0.05 for distance and for near it was 0.61 ± 0.05. After the intervention, the acuities improved significantly for distance (0.2 ± 0.27; P visual rehabilitation was especially found in those activities related to their studying lifestyle like copying from the blackboard (P visual rehabilitation, especially with those activities which are related to their academic output. It is important for these children to have an early visual rehabilitation to decrease the impairment associated with these decreased visual output and to enhance their learning abilities.

  20. A Systematic Review of the Literature on Parenting of Young Children with Visual Impairments and the Adaptions for Video-Feedback Intervention to Promote Positive Parenting (VIPP).

    Science.gov (United States)

    van den Broek, Ellen G C; van Eijden, Ans J P M; Overbeek, Mathilde M; Kef, Sabina; Sterkenburg, Paula S; Schuengel, Carlo

    2017-01-01

    Secure parent-child attachment may help children to overcome the challenges of growing up with a visual or visual-and-intellectual impairment. A large literature exists that provides a blueprint for interventions that promote parental sensitivity and secure attachment. The Video-feedback Intervention to promote Positive Parenting (VIPP) is based on that blueprint. While it has been adapted to several specific at risk populations, children with visual impairment may require additional adjustments. This study aimed to identify the themes that should be addressed in adapting VIPP and similar interventions. A Delphi-consultation was conducted with 13 professionals in the field of visual impairment to select the themes for relationship-focused intervention. These themes informed a systematic literature search. Interaction, intersubjectivity, joint attention, exploration, play and specific behavior were the themes mentioned in the Delphi-group. Paired with visual impairment or vision disorders, infants or young children (and their parents) the search yielded 74 articles, making the six themes for intervention adaptation more specific and concrete. The rich literature on six visual impairment specific themes was dominated by the themes interaction, intersubjectivity, and joint attention. These themes need to be addressed in adapting intervention programs developed for other populations, such as VIPP which currently focuses on higher order constructs of