Adaptive software for head-operated computer controls

Motor Performance, Mental Workload and Self-Efficacy Dynamics during Learning of Reaching Movements throughout Multiple Practice Sessions

The human capability to learn new motor skills depends on the efficient engagement of cognitive-motor resources, as reflected by mental workload, and psychological mechanisms (e.g., self-efficacy). While numerous investigations have examined the relationship between motor behavior and mental workload or self-efficacy in a performance context, a fairly limited effort focused on the combined examination of these notions during learning. Thus, this study aimed to examine their concomitant dynamics during the learning of a novel reaching skill practiced throughout multiple sessions. Individuals had to learn to control a virtual robotic arm via a human-machine interface by using limited head motion throughout eight practice sessions while motor performance, mental workload, and self-efficacy were assessed. The results revealed that as individuals learned to control the robotic arm, performance improved at the fastest rate, followed by a more gradual reduction of mental workload and finally an increase in self-efficacy. These results suggest that once the performance improved, less cognitive-motor resources were recruited, leading to an attenuated mental workload. Considering that attention is a primary cognitive resource driving mental workload, it is suggested that during early learning, attentional resources are primarily allocated to address task demands and not enough are available to assess self-efficacy. However, as the performance becomes more automatic, a lower level of mental workload is attained driven by decreased recruitment of attentional resources. These available resources allow for a reliable assessment of self-efficacy resulting in a subsequent observable change. These results are also discussed in terms of the application to the training and design of assistive technologies.

Changes in motor performance and mental workload during practice of reaching movements: a team dynamics perspective

Few investigations have examined mental workload during motor practice or learning in a context of team dynamics. This study examines the underlying cognitive-motor processes of motor practice by assessing the changes in motor performance and mental workload during practice of reaching movements. Individuals moved a robotic arm to reach targets as fast and as straight as possible while satisfying the task requirement of avoiding a collision between the end-effector and the workspace limits. Individuals practiced the task either alone (HA group) or with a synthetic teammate (HRT group), which regulated the effector velocity to help satisfy the task requirements. The findings revealed that the performance of both groups improved similarly throughout practice. However, when compared to the individuals of the HA group, those in the HRT group (1) had a lower risk of collisions, (2) exhibited higher performance consistency, and (3) revealed a higher level of mental workload while generally perceiving the robotic teammate as interfering with their performance. As the synthetic teammate changed the effector velocity in specific regions near the workspace boundaries, individuals may have been constrained to learn a piecewise visuomotor map. This piecewise map made the task more challenging, which increased mental workload and perception of the synthetic teammate as a burden. The examination of both motor performance and mental workload revealed a combination of both adaptive and maladaptive team dynamics. This work is a first step to examine the human cognitive-motor processes underlying motor practice in a context of team dynamics and contributes to inform human-robot applications.

Effect of dynamic keyboard and word-prediction systems on text input speed in persons with functional tetraplegia

Information technology plays a very important role in society. People with disabilities are often limited by slow text input speed despite the use of assistive devices. This study aimed to evaluate the effect of a dynamic on-screen keyboard (Custom Virtual Keyboard) and a word-prediction system (Sibylle) on text input speed in participants with functional tetraplegia. Ten participants tested four modes at home (static on-screen keyboard with and without word prediction and dynamic on-screen keyboard with and without word prediction) for 1 mo before choosing one mode and then using it for another month. Initial mean text input speed was around 23 characters per minute with the static keyboard and 12 characters per minute with the dynamic keyboard. The results showed that the dynamic keyboard reduced text input speed by 37% compared with the standard keyboard and that the addition of word prediction had no effect on text input speed. We suggest that current forms of dynamic keyboards and word prediction may not be suitable for increasing text input speed, particularly for subjects who use pointing devices. Future studies should evaluate the optimal ergonomic design of dynamic keyboards and the number and position of words that should be predicted.

Software wizards to adjust keyboard and mouse settings for people with physical impairments

CONTEXT/OBJECTIVE

This study describes research behind two software wizards that help users with physical impairments adjust their keyboard and mouse settings to meet their specific needs. The Keyboard Wizard and Pointing Wizard programs help ensure that keyboard and pointing devices are properly configured for an individual, and reconfigured as the user's needs change. We summarize four effectiveness studies and six usability studies.

METHODS

Studies involved participants whose physical impairments affect their ability to use a keyboard and mouse. Effectiveness studies used an A-B-A design, with condition A using default Windows settings and condition B using wizard-recommended settings. Primary data were performance metrics for text entry and target acquisition. Usability studies asked participants to run through each wizard, with no outside guidance. Primary data were completion time, errors made, and user feedback.

RESULTS

The wizards were effective at recommending new settings for users who needed them and not recommending them for users who did not. Sensitivity for StickyKeys, pointer speed, and object size algorithms was 100%. Specificity for StickyKeys and pointer speed was over 80%, and 50% for object size. For those who needed settings changes, the recommendations improved performance, with speed increases ranging from 9 to 59%. Accuracy improved significantly with the wizard recommendations, eliminating up to 100% of errors. Users ran through the current wizard software in less than 6 minutes. Ease-of-use rating averaged over 4.5 on a scale of 1 to 5.

CONCLUSION

The wizards are a simple yet effective way of adjusting Windows to accommodate physical impairments.

A novel five degree of freedom user command controller in people with spinal cord injury and non-injured for full upper extremity neuroprostheses, wearable powered orthoses and prosthetics

An independent lifestyle requires the ability to place the hand in the complete workspace in concert with hand grasp and release. A novel user command controller monitoring head position for purpose of controlling hand location and orientation is proposed and demonstrated. The controller detected five degrees of freedom which were applied to upper limb movements including forearm and hand placement in three-dimensional space. The controller was evaluated by having subjects complete tracking tasks manipulating a simulated on-screen upper limb representation. Thirteen of the eighteen subjects assessed using the controller had sustained a spinal cord injury at or above the sixth cervical vertebra. Two of the injured subjects with decreased cervical spine mobility were unable to operate the controller. The remaining subjects performed the tracking tasks effectively after minimal training. This simple five-degree of freedom controller has been proposed for the use by those disabled by upper limb amputation, paralysis, weakness or hypertonicity.

Alternative communication systems for people with severe motor disabilities: a survey

We have now sufficient evidence that using electrical biosignals in the field of Alternative and Augmented Communication is feasible. Additionally, they are particularly suitable in the case of people with severe motor impairment, e.g. people with high-level spinal cord injury or with locked-up syndrome. Developing solutions for them implies that we find ways to use sensors that fit the user's needs and limitations, which in turn impacts the specifications of the system translating the user's intentions into commands. After devising solutions for a given user or profile, the system should be evaluated with an appropriate method, allowing a comparison with other solutions. This paper submits a review of the way three bioelectrical signals--electromyographic, electrooculographic and electroencephalographic--have been utilised in alternative communication with patients suffering severe motor restrictions. It also offers a comparative study of the various methods applied to measure the performance of AAC systems.

Investigating Grid-Based Navigation

Hands-free speech-based technology can be a useful alternative for individuals that find traditional input devices, such as keyboard and mouse, difficult to use. Various speech-based navigation techniques have been examined, and several are available in commercial software applications. Among these alternatives, grid-based navigation has demonstrated both potential and limitations. In this article, we discuss an empirical study that assessed the efficacy of two enhancements to grid-based navigation: magnification and fine-tuning. The magnification capability enlarges the selected region when it becomes sufficiently small, making it easier to see the target and cursor. The fine-tuning capability allows users to move the cursor short distances to position the cursor over the target. The study involved one group of participants with physical disabilities, an age-matched group of participants without disabilities, and a third group that included young adults without disabilities. The results confirm that both magnification and fine-tuning significantly improved the participants’ performance when selecting targets, especially small targets. Providing either, or both, of the proposed enhancements substantially reduced the gaps in performance due to disability and age. The results will inform the design of speech-based target selection mechanism, allowing users to select targets faster while making fewer errors.

Research in computer access assessment and intervention

Computer access technology (CAT) allows people who have trouble using a standard computer keyboard, mouse, or monitor to access a computer. CAT is critical for enhancing the educational and vocational opportunities of people with disabilities. Choosing the most appropriate CAT is a collaborative decision-making process involving the consumer, clinician(s), and third party payers. The challenges involved and potential technological solutions are discussed.

Development and evaluation of a head-controlled human-computer interface with mouse-like functions for physically disabled users

OBJECTIVES

The objectives of this study were to develop a pointing device controlled by head movement that had the same functions as a conventional mouse and to evaluate the performance of the proposed device when operated by quadriplegic users.

METHODS

Ten individuals with cervical spinal cord injury participated in functional evaluations of the developed pointing device. The device consisted of a video camera, computer software, and a target attached to the front part of a cap, which was placed on the user's head. The software captured images of the target coming from the video camera and processed them with the aim of determining the displacement from the center of the target and correlating this with the movement of the computer cursor. Evaluation of the interaction between each user and the proposed device was carried out using 24 multidirectional tests with two degrees of difficulty.

RESULTS

According to the parameters of mean throughput and movement time, no statistically significant differences were observed between the repetitions of the tests for either of the studied levels of difficulty.

CONCLUSIONS

The developed pointing device adequately emulates the movement functions of the computer cursor. It is easy to use and can be learned quickly when operated by quadriplegic individuals.

Toward automatic adjustment of pointing device configuration to accommodate physical impairment

PURPOSE

Software was developed which makes recommendations regarding configuration of a computer pointing device, such as a mouse, to accommodate a person's physical impairment. Specifically, a software agent automatically recommends a setting for the computer's control-display gain based on observations of a user's performance in a target selection task.

METHOD

The software agent makes its recommendations based on available adjustment settings in the existing operating system. The agent was evaluated in studies with 12 participants who have motor impairments.

RESULTS

The agent-selected gain was not associated with significant improvements in selection time or error-free performance compared with the operating system's default gain. Across participants and trials, gain did not have a significant effect on selection time except at the lowest gain settings tested. However, two participants did have notable and consistent improvement in selection time and error-free performance using the agent-selected gain; gain across trials had a significant effect on number of target entries and number of submovements; and a post-hoc analysis indicated improved target selection time when varying both target size and control-display gain.

CONCLUSION

These observations provide possible avenues for future work, although the current study indicates that changes to control-display gain, alone, are unlikely to offer improvements in speed or accuracy for the general population of people with motor impairments.