Type of visual feedback during practice influences the precision of the acquired internal model of a complex visuo-motor transformation

This study investigated the influence of the type of visual feedback during practice with a complex visuo-motor transformation of a sliding two-sided lever on the acquisition of an internal model of the transformation. Three groups of participants, who practised with different types of visual feedback, were compared with regard to movement accuracy, curvature and movement time. One group had continuous visual feedback during practice and two groups were presented terminal visual feedback, either only the end position of the movement or the end position together with the trajectory of the cursor. Results showed that continuous visual feedback led to more precise movement end positions during practice than terminal visual feedback, but to less precise movements during open-loop tests. This finding indicates that terminal visual feedback supports the development of a precise internal model of a new visuo-motor transformation. However, even terminal feedback of the cursor trajectory during practice did not result in an internal model, which includes appropriate curvatures of hand movements. STATEMENT OF RELEVANCE: This paper presents results on the influence of type of visual feedback on learning the complex motor skill of controlling a sliding lever. These findings contribute to the conceptual basis of optimised training procedures for the acquisition of sensori-motor skills required for the mastery of instruments utilised in minimally invasive surgery.     

Display Movement Velocity and Dynamic Visual Search Performance

In practice, many visual search tasks are performed under dynamic conditions. An experiment was conducted here to test visual search strategy adopted by a person in a dynamic visual search and to investigate the effects of display movement velocity on search time and detection accuracy in it. Thirty‐five participants were randomly tested with all 10 angular velocities of 0, 2, 4, 6, 8, 10, 12, 14, 16, and 32 deg/s. The data obtained fitted the random search model well. The results revealed that observers utilized a random search strategy during the dynamic visual search process and that display movement velocity influenced search performance. In comparison with static visual search, an angular velocity faster than 4 deg/s resulted in a significant decrement in search performance. The variations of duration of individual fixations, the probability of target detection in a single fixation and visual lobe area were discussed. The obtained relationships between display movement velocity, search time and detection accuracy can serve as a useful guide for designing a dynamic search task, thus helping to maximize the cost‐effectiveness of dynamic search tasks while minimizing errors and misses during the search process.     

Foundation for improved interaction by individuals with visual impairments through multimodal feedback

Through an investigation of how the performance of people who have normal visual capabilities is affected by unimodal, bimodal, and trimodal feedback, this research establishes a foundation for presenting effective feedback to enhance the performance of individuals who have visual impairments. Interfaces that employ multiple feedback modalities, such as auditory, haptic, and visual, can enhance user performance for individuals with barriers limiting one or more channels of perception, such as a visual impairment. Results obtained demonstrate the effects of different feedback combinations on mental workload, accuracy, and performance time. Future, similar studies focused on participants with visual impairments will be grounded in this work. Published online: 6 November 2002     

Effects of real‐time visual feedback on pre‐service teachers' singing

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 VFT. Forty participants from an undergraduate music teacher education programme were randomly assigned to three groups. The first two groups were assigned the teacher and student versions of Sing & See, respectively, and the third group served as a control group without access to the software. The experimental groups were given 12 weeks to use the software for vocal training on a self‐regulated basis. The technique of complex selections (TCS) was designed to assess the pitch accuracy and richness of vocal timbre. Pre‐ and post‐test singing tasks showed that the participants from the experimental groups significantly improved their vocal timbre. A questionnaire survey conducted after the training period found that most of the participants in the experimental s were positive about the effectiveness of VFT software in vocal training. As future leaders in the implementation of music education technology, pre‐service music teachers expressed a positive attitude towards the use of VFT as a technology‐enhanced learning (TEL) component in music education.     

Accuracy of non-visual directional pointing with various manual input devices

In a self-testing vision screener, examinees use an input device for pointing the orientation of the targets, which are presented inside the vision screener. Examinees operate the input device without visual feedback. In the present study, the suitability of pointing devices was evaluated for conditions such as are present in a self-testing vision screener. The evaluation consisted of an experimental assessment of pointing accuracy and recording subjective ratings while using the various devices. Six commercially available computer input devices – a joystick, a gamepad, a trackball, two track pads and a PC mouse - were evaluated under visual conditions similar to those that would be present when using a self-testing vision screener.Pointing accuracy was found to vary significantly with the type of device (F(3.2, 93.1) = 3.937, p = 0.009) and the effect of the device on pointing accuracy was important (partial η² = 0.120). The most accurate pointing was achieved when participants used the joystick. Using the joystick, a mean of 96.8% (SD = 4.3%) of pointing trials resulted in the correct orientation. If only diagonal orientations are considered, the correct pointing rate increased to a mean of 99.5% (SD = 1.5%) when using the joystick.In terms of the subjective ranking, the gamepad and the joystick achieved the best and the second best ranks respectively, whereas the trackball was the least preferred device.Based on our findings, we recommend using a joystick as an input device in pointing tasks in order to minimize the effects of suboptimal visual feedback on motor performance. As for the particular case of testing visual acuity, various procedures are suggested. Thus, the effect of suboptimal visual feedback on the outcome of the acuity test is reduced.     

Automation usage decisions: controlling intent and appraisal errors in a target detection task

BACKGROUND: It was proposed that misuse and disuse often occur because operators (a) cannot determine if automation or a nonautomated alternative maximizes the likelihood of task success (appraisal errors) or (b) know the utilities of the options but disregard this information when deciding to use automation (intent errors). OBJECTIVE: This investigation assessed the effectiveness of performance feedback, a procedure developed to attenuate appraisal errors, and scenario training, an intervention designed to decrease intent errors. METHODS: Operators given feedback were told how many errors they and an automated device made on a target detection task. Scenario training took operators through the thought processes of optimal decision makers after the utilities of the automated and nonautomated alternatives had been determined. Following 200 training trials, participants chose between relying on their observations or an automated device. RESULTS: There was little misuse, but disuse rates were high (84%) among operators receiving neither feedback nor scenario training. Operators paired with a more accurate machine and given feedback made approximately twice as many errors as the automated device. Nevertheless, intent errors were commonplace; 55% of the operators who received feedback without scenario training did not rely on automation. Feedback effectiveness was enhanced when used in conjunction with scenario training; the disuse rate decreased to 29%. CONCLUSION: A combination of feedback and scenario training was more effective in mitigating disuse than either intervention used in isolation. APPLICATION: An important application of these findings is that operator training programs should incorporate techniques to control intent and appraisal errors.     

Office ergonomics training and a sit-stand workstation: Effects on musculoskeletal and visual symptoms and performance of office workers

Work Related Musculoskeletal Disorders (WMSDs) among office workers with intensive computer use is widespread and the prevalence of symptoms is growing. This randomized controlled trial investigated the effects of an office ergonomics training combined with a sit-stand workstation on musculoskeletal and visual discomfort, behaviors and performance. Participants performed a lab-based customer service job for 8?h per day, over 15 days and were assigned to: Ergonomics Trained (n?=?11) or Minimally Trained (n?=?11). The training consisted of: a 1.5-h interactive instruction, a sit/stand practice period, and ergonomic reminders. Ergonomics Trained participants experienced minimal musculoskeletal and visual discomfort across the 15 days, varied their postures, with significantly higher performance compared to the Minimally Trained group who had a significantly higher number of symptoms, suggesting that training plays a critical role. The ability to mitigate symptoms, change behaviors and enhance performance through training combined with a sit-stand workstation has implications for preventing discomforts in office workers.     

Effects of brief training on use of automated external defibrillators by people without medical expertise

OBJECTIVE: This study examined the effect of three types of brief training on the use of automatic external defibrillators (AEDs) by 43 lay users. BACKGROUND: Because AEDs were recently approved for home use, brief training for nonprofessional users needs investigation. METHOD: During training, the exposure training group read an article about AEDs that provided no information on how to operate them; the low-training group inspected the AED and read the operating instructions in the paper-based manual but was not allowed to use the device; and the high-training group watched a training video and performed a mock resuscitation using the AED but no manikin. All participants returned 2 weeks later and performed a surprise simulated AED resuscitation on a manikin. RESULTS: Most participants in each training group met criteria of minimally acceptable performance during the simulated manikin resuscitation, as measured by time to first shock, pad placement accuracy, and safety check performance. All participants who committed errors were able to successfully recover from them to complete the resuscitation. Compared with exposure training, the low and high training had a beneficial effect on time to first shock and errors. CONCLUSION: Untrained users were able to adequately use this AED, demonstrating walk-up-and-use usability, but additional brief training improved user performance. APPLICATION: This study demonstrated the importance of providing high-quality but brief training for home AED users. In conjunction with other findings, the current study helps demonstrate the need for well-designed training for consumer medical devices.     

Investigating the effects of multimodal feedback through tracking state in pen-based interfaces

A tracking state increases the bandwidth of pen-based interfaces. However, this state is difficult to detect with default visual feedback. This paper reports on two experiments that are designed to evaluate multimodal feedback for pointing tasks (both 1D and 2D) in tracking state. In 1D pointing experiments, results show that there is a significant effect for input types on movement time while feedback type and the use of different hands for receiving feedback (i.e. the dominant or non-preferred hand) do not affect movement time significantly. We also report that there is a significant effect for feedback types and input device types on error rate while the choice of hand (used for detecting feedback vibrations) does not affect the error rate significantly. In the 2D pointing experiment, results show that there are no significant effects for either input type or the use of different hands on movement time while feedback type affects movement time significantly. Results for both the 1D and 2D pointing tasks show that tactile plus visual feedback can improve accuracy and audio is not efficient to give user feedback in tracking state. This paper proposes several guidelines for feedback design in tracking state. We believe these results can aid designers of pen-based interfaces.     

Vision for Performance in Virtual Environments: The Role of Feedback Timing

This work explores how people use visual feedback when performing simple reach-to-grasp movements in a tabletop virtual environment. In particular we investigated whether visual feedback is required for the entire reach or whether minimal feedback can be effectively used. Twelve participants performed reach-to-grasp movements toward targets at two locations. Visual feedback about the index finger and thumb was provided in four conditions: vision available throughout the movement, vision available up to peak wrist velocity, vision available until movement initiation, or vision absent throughout the movement. It was hypothesized that vision available until movement onset would be an advantage over a no vision situation yet not attain the performance observed when vision was available up to peak velocity. Results indicated that movement time was longest in the no vision condition but similar for the three conditions where vision was available. However, deceleration time and peak aperture measures suggest grasping is more difficult when vision is not available for at least the first third of the movement. These results suggest that designers of virtual environments can manipulate the availability of visual feedback of one's hand without compromising interactivity. This may be applied, for example, when detailed rendering of other aspects of the environmental layout is more important, when motion lag is a problem or when hand/object concealment is an issue.     

Age differences in the control of a precision reach to grasp task within a desktop virtual environment

The purpose of this experiment is to investigate the fine motor performance of young and older adults on a reach to grasp task in a desktop virtual environment with increasing precision requirements. Aging brings about potential loss of an individual's function due to disease, injury, or the degenerative nature of aging itself. Three-dimensional virtual environments have been identified as systems with good potential to ameliorate such problems in older individuals, and precise fine motor skills represent an important class of functional skills. Two groups of participants (Young, n=10, mean age 21.3 years, range 20–24, senior, n=10, mean age 70.7 years, range 60–85) performed a reach to grasp in a desktop virtual environment with simple, low contrast graphics. Results indicate that visual feedback of the hand for sensory guidance of movement did not improve motor performance for either group, and that as precision requirements of the task increased, age group differences in movement time and peak grasp aperture also increased. These findings extend the literature on age group differences in human motor control across the lifespan and differ from previous studies which showed presence of visual feedback of the hand improved motor performance in young adults. Differences in luminance contrast levels in past studies and the current one suggest that control over this feature of the visual scene is an important design consideration for all end-users and warrants additional investigation. Additional recommendations for age-specific design of three dimensional user interfaces include usage of tangibles that are sufficient in size to limit detrimental effects for older adults.     

Mechanisms of vibration-induced interference with manual control performance

Abstract

An experiment is described in which eight subjects performed three simple tasks (A, B and C) in static conditions and during exposure to whole-body vertical (z-axis) vibration at 0-5 and 40 Hz, at an acceleration magnitude of 2-1 ms^-2 r.m.s. All subjects performed all conditions with and without an arm support. The objective was to explore the mechanisms that may cause disruption of manual control performance during vibration exposure. With task A subjects simply held a control with no visual feedback of activity at the control. With task B, subjects used the control to hold a controlled element stationary on a display. Task C was the same as task B, except that subjects had improved visual feedback of movement of the controlled element. Results showed that both 0-5 and 40 Hz vibration caused significant increases in control activity at frequencies of up to about 1 Hz compared with the condition without vibration. With visual feedback in task C, subjects were able to detect drifting of the controlled element on the display and introduced compensatory control activity at frequencies above about 0 2 Hz. The arm support reduced the magnitude of vibration transmitted to the control at 4-0 Hz, but did not otherwise change the results.     

Endogenous brain–machine interface based on the correlation of EEG maps

In this paper, a non-invasive endogenous brain–machine interface (BMI) based on the correlation of EEG maps has been developed to work in real-time applications. The classifier is able to detect two mental tasks related to motor imagery with good success rates and stability. The BMI has been tested with four able-bodied volunteers. First, the users performed a training with visual feedback to adjust the classifier. Afterwards, the users carried out several trajectories in a visual interface controlling the cursor position with the BMI. In these tests, score and accuracy were measured. The results showed that the participants were able to follow the targets during the performed trajectory, proving that the EEG mapping correlation classifier is ready to work in more complex real-time applications aimed at helping people with a severe disability in their daily life.     

Effect of tactile feedback on movement speed and precision during work-related tasks using a computer mouse

Effects of tactile feedback on movement accuracy and speed were studied. Younger and older participants performed three tasks (1, select and drag word; 2, menu navigation; 3, select and drag cell) using commercial software and a mouse with or without tactile feedback. Task time and error number were recorded. Tasks were divided according to presence or absence of tactile feedback, and participants were divided into subgroups (high, average, low) based on Task 1 performance. Overall, older participants took longer (p < .0001) and made more errors (p < .001) than younger participants. There was an effect of feedback by task in younger participants for all six outcomes (p < 0.02). At the task level, with feedback, younger participants reduced performance time (13%) and errors (24%) on Task 1. Low- and average-performance younger participants benefited most from feedback for Task 1. Older low-performance participants also benefited from feedback for Task 1. For Task 3, older participants tended to take more time and make more errors with feedback. Tactile feedback may enhance performance when feedback is event related. Older people may not integrate sensation as well as younger individuals to enhance performance. Potential applications of this research include the development of tactile feedback interfaces to facilitate computer use.     

The Role of Visual Feedback and Age When Grasping,Transferring and Passing Objects in Virtual Environments

ABSTRACT

Visual feedback about one’s own movements can be important for effective performance in natural and computer-generated environments. Previous work suggested that, for young adults, performance in virtual environments was influenced by the presence of a crude representation of the hand in a task-specific fashion. The current study was performed to determine whether this pattern of results holds across the lifespan. Specifically, we were interested in determining whether a representation of the hand is useful for movement performance in children, middle adults, and older adults when they reach to grasp an object, transfer it between their two hands, or receive it from a partner. Surprisingly, visual feedback condition had very little effect on performance in the current experiment, with the exception that participants in all three age groups altered how wide they opened their hand when grasping depending on visual condition. Patterns of reach and grasp performance changed across task depending on age, with older adults displaying different patterns than children and middle-aged adults. These results suggest that feedforward planning and the use of feedback are modulated by both age and task.     

Precognitive control: open- and closed-loop steering in a lane-change manoeuvre

Abstract

This paper presents two experiments in which steering a lane-change manoeuvre is analysed as a precognitive control task. The suggestion that the dependence on instantaneous visual feedback is low during such a task was tested by analysing steering performance under conditions both with and without visual occlusion. Steering force served as the main independent variable in experiment I, which was performed in a fixed-base driving simulator. A 1 s visual occlusion period during the initial steering-wheel movement to the left was given every other manoeuvre. The results indicate that steering force reduces steering-wheel amplitude variability, this effect also being reflected in the maximum heading angle variability.

Steering-wheel angle amplitude was the main independent variable in experiment II, which was carried out in the instrumented car. In this experiment the duration of the occlusion period was 3 s, i.e. covering the complete pull-out phase of the manoeuvre. The results show that variability in steering-wheel movement amplitude increases about linearly with the amplitude: standard deviations are about 9% of the amplitude. For both experiments I and II the results correspond quite well with those of an earlier reproduction experiment. Regarding the withdrawal of visual feedback it appears that occlusion affects the mutual tuning of steering amplitude and timing, rather than affecting these quantities separately. The vehicle-motion effects resulting from occlusion are relatively small and it can be concluded therefore that a temporary withdrawal of visual feedback has no dramatic effects in the pre-programmed task considered here.     

Evaluation of a two cursor control device for development of a powered laparoscopic surgical tool

The current study was performed to test two electronic cursor control devices (a Touchpad and a MicroJoystick) for use in an articulating powered laparoscopic tool. A simple target acquisition test was conducted to test how well the cursor control devices could be manipulated and how accurate they were (including endpoint and movement path). The study varied the width (0.27, 0.54 and 1.07 cm) of the target as well as the hand position used (thumb and index finger control). Additionally, each participant was able to choose their ideal operating cursor speed for each cursor control device. The MicroJoystick had a higher throughput and movement variability than the Touchpad. In all other categories tested, the cursor control devices did not differ significantly. The speed of the cursor control devices did not affect the performance of the devices; therefore, the ideal cursor speed could be chosen by the participant. Finally, the hand position did not affect the performance of the devices. This experiment found both hand positions, cursor control devices and all speeds could be used to effectively manipulate an articulating end-effector in a powered, cauterising, laparoscopic tool. This article addresses the advantages and limitations of two control mechanisms for laparoscopic tool controls considering both the subjective and objective data. The controls are tested in two hand positions to test how well the participants can manipulate the device while minimising perceived fatigue.     

基于视-触跨模态感知的智能导盲系统

盲人活动援助是盲人日常生活的重要组成部分。这些技术大多用于帮助盲人导航和躲避障碍物,很少有研究将地面信息转换成一种给用户直观感受的触觉信息。为了满足上述需求,本文提出了一种可以提供触觉反馈的盲人辅助地面识别智能导盲杖系统。试图利用深度生成对抗训练的方法来产生振动触觉刺激,使用改进的DiscoGAN训练了我们的端到端生成网络。为了训练我们的网络,构建了视触跨模态数据集GroVib。通过上机实验和实物实验来评估方案的可行性,通过上机实验结果表明参与者通过触觉识别地面的准确率为84.7%,触觉的平均真实感受得分为71.3,在真实场景实验中,参与者只需平均3.35次尝试就可以根据触觉反馈来识别地面。     

Real-time evaluation and visualization of learner performance in a mixed-reality environment for clinical breast examination

We investigate the efficacy of incorporating real-time feedback of user performance within mixed-reality environments (MREs) for training real-world tasks with tightly coupled cognitive and psychomotor components. This paper presents an approach to providing real-time evaluation and visual feedback of learner performance in an MRE for training clinical breast examination (CBE). In a user study of experienced and novice CBE practitioners (n = 69), novices receiving real-time feedback performed equivalently or better than more experienced practitioners in the completeness and correctness of the exam. A second user study (n = 8) followed novices through repeated practice of CBE in the MRE. Results indicate that skills improvement in the MRE transfers to the real-world task of CBE of human patients. This initial case study demonstrates the efficacy of MREs incorporating real-time feedback for training real-world cognitive-psychomotor tasks.     

An evaluation of the virtual curvature with the StickGrip haptic device: a case study

Dynamic simulation of distance to the physical surface could promote the development of new inexpensive tools for blind and visually impaired users. The StickGrip is a haptic device comprised of the Wacom pen input device added with a motorized penholder. The goal of the research presented in this paper was to assess the accuracy and usefulness of the new pen-based interaction technique when the position and displacement of the penholder in relation to the pen tip provided haptic feedback to the user about the distance to the physical or virtual surface of interaction. The aim was to examine how accurately people are able (1) to align the randomly deformed virtual surfaces to the flat surface and (2) to adjust the number of surface samples having a randomly assigned curvature to the template having the given curvature and kept fixed. These questions were approached by measuring both the values of the adjusted parameters and the parameters of the human performance, such as a ratio between inspection time and control time spent by the participants to complete the matching task with the use of the StickGrip device. The test of the pen-based interaction technique was conducted in the absence of visual feedback when the subject could rely on the proprioception and kinesthetic sense. The results are expected to be useful for alternative visualization and interaction with complex topographic and mathematical surfaces, artwork, and modeling.