Effect of visual perception, visual function, cognition, and personality on power wheelchair use in adults

Cognitive status is associated with performance of manual wheelchair skills in hospitalized older adults

PURPOSE

To examine the relationship between manual wheelchair skills and cognitive function in hospitalized older adults.

METHODS

The observational study included older adults who used a manual wheelchair following hip/knee surgery. Participants underwent a series of tests to evaluate manual wheelchair skills and cognitive performance. Four items appearing on the Wheelchair Skills Test: brake handling (locking/unlocking), a 10-metre forward roll, a 2-metre backward roll and rotating in place, were used to evaluate manual wheelchair skills. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA), Trail Making Test (TMT), the Clock Drawing Test, and the Loewenstein Occupational Therapy Cognitive Assessment. The relationship between wheelchair skills and cognitive scores was assessed by a series of univariate linear regression analyses.

RESULTS

Fifty older adults, aged 65-85, participated in the study. The MoCA-7 (orientation) explained 19.3% of the variance related to the turn in place wheelchair skill, 18.8% of the variance related to the two-metre backwards roll and 31.9% of the variance related to the 10-metre forward roll. The addition of gender (to the MoCA-7) increased the explained variance related to the 10-metre forward roll and turn in place skills to 38.5% and 28.5%, respectively. As for the brakes handling skill test, gender explained 18.3% of the variance. The addition of the CDT (to gender) increased the explained variance for the brakes handling skill to 31.4%.

CONCLUSIONS

Because cognitive impairments negatively affect the performance of wheelchair skills, rehabilitation therapists may need to adjust wheelchair mobility training methods for cognitively impaired older adults.Implication for rehabilitationGiven the prevalence of older adults with cognitive impairments who use manual wheelchairs, it is critical to better understand the relationship between cognition and wheelchair skills.Poor results reported on the cognitive tests, specifically, visual attention and orientation, were found to be associated with poor performance of four manual wheelchair skills.Rehabilitation therapists should consider the cognitive status of older adults when teaching manual wheelchair skills, specifically in new users. Future studies should examine whether a customized preparation program, enhancing visuospatial orientation, can benefit manual wheelchair control in older adults.

Initial validation of the powered mobility device autonomy residential screen (PoMoDARS)

BACKGROUND

The Powered Mobility Device Autonomy Residential Screen (PoMoDARS) is a new tool to enable clinicians to screen resident capacity and performance skills for powered mobility device (PMD) use in residential aged care settings. The PoMoDARS is context specific, time efficient and promotes resident autonomy and safety.

AIMS

To (i) undertake initial face and content validation of the PoMoDARS, and (ii) use the research findings to make any modifications.

METHODS

A mixed-methods study design, underpinned by Classical Test Theory. Eight clinicians completed 20 PoMoDARS screens and provided both quantitative and qualitative feedback on item importance and ease of use within a formal interview.

RESULTS

Initial face and content validity of the PoMoDARS were supported, with small modifications made to item descriptors and instructions.

CONCLUSIONS

The PoMoDARS has been developed for use in residential aged care settings to screen resident PMD use. While initial validation has been undertaken, further studies to determine the reliability of the tool and continue the validation process are required.

SIGNIFICANCE

Older adults in residential aged care facilities benefit greatly from the autonomy gained through PMD use. The PoMoDARS promotes collaboration between occupational therapists, nurses, and the wider team to support residents and safe PMD use.

Policy Analysis on Power Seat Elevation Systems

In the early 2000s the Centers for Medicare and Medicaid Services determined that power seat elevation systems did not meet the definition of durable medical equipment, and therefore are non-covered items. Yet, power seat elevation systems are covered by other funding sources, and many power wheelchair users utilize these systems regularly when performing tasks such as transferring, reaching, and looking at objects in environments designed for ambulatory people. Adjusting for height when performing these tasks may reduce the onset of pain and comorbidities. To improve access to power seat elevation systems, a clinical team of 4 Clinician Task Force members investigated applicable literature, compiled evidence, and evaluated existing policies to explain the medical nature of power seat elevation systems as a part of a greater interprofessional effort. This manuscript aims to analyze Medicare's policy decision that power seat elevation systems are not primarily medical in nature using Bardach's 8-step framework. As a special communication, this will inform health care professionals of the medical nature of power seat elevation systems and the evidence-based conditions under which power wheelchair users may need power seat elevation systems, as well as empower clinicians to engage in policy directives to affect greater change.

Skills assessment metrics of electric powered wheelchair driving in a virtual environment: a survey

The purpose of this review is to present studies on the parameters for assessing the skills of users of electric wheelchair driving simulators in a virtual environment. In addition, this study also aims to identify the most widely used and validated parameters for the quantification of electric wheelchair driving ability in a virtual environment and to suggest challenges for future research. To carry out this research, the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were adopted. Literature searches in English, French, and Portuguese were conducted up to December 2020 in the PubMed, SciELO, Science Direct, World Wide Science, and Scopus databases. The keywords used were electric wheelchair, simulator, performance indicators, performance skills, driving skills, training platform, virtual environment, and virtual reality. We excluded studies involving "real" wheelchairs without a simulator in a virtual environment. We have selected a total of 42 items. In these studies, we identified 32 parameters (3 qualitative and 29 quantitative) that are used as parameters for the evaluation of the ability to control a powered wheelchair in a virtual environment. Although the amount of research in this area has increased significantly in recent years, additional studies are still needed to provide a more accurate and objective assessment of skills among the target population. A challenge for future work is the increasing application of artificial intelligence techniques and the exploration of biomedical data measurements, which may be a promising alternative to improve the quantification of user competencies.

Relationships between Cognitive Functioning and Powered Mobility Device Use: A Scoping Review

Background. Powered mobility devices (PMD) promote independence, social participation, and quality of life for individuals with mobility limitations. However, some individuals would benefit from PMD, but may be precluded access. This is particularly true for those with cognitive impairments who may be perceived as unsafe and unable to use a PMD. This study explored the relationships between cognitive functioning and PMD use. The objectives were to identify cognitive functions necessary to use a PMD and describe available PMD training approaches. Methods. A scoping review was undertaken. Results. Seventeen studies were included. Four examined the predictive or correlational relationships between cognitive functioning and PMD use outcomes with intellectual functions, visual and visuospatial perception, attention, abstraction, judgement, organization and planning, problem solving, and memory identified as having a relation with PMD use outcome in at least one study. Thirteen others studied the influence of PMD provision or training on users’ PMD capacity and cognitive outcomes and reported significative improvements of PMD capacities after PMD training. Six studies found improved cognitive scores after PMD training. Conclusions. Cognitive functioning is required to use a PMD. Individuals with heterogeneous cognitive impairment can improve their PMD capacities. Results contribute to advancing knowledge for PMD provision.

Evaluating a Therapeutic Powered Mobility Camp for Children with Severe Cerebral Palsy

Background. Children and youth with severe cerebral palsy (CP) have limited independent mobility, which affects opportunities for overall development. Purpose. To examine the effectiveness of Power Fun, a therapeutic powered mobility summer camp. Methods. A quasi-experimental, repeated-measure design was used, with participants acting as their own control. Twenty-four participants with severe CP (aged 7-20 years) attended Power Fun for three weeks, five days/week. Assessments of powered mobility skills and functional mobility goals were conducted three weeks before the camp (T1), at baseline (T2), postintervention (T3), and at three-week follow-up (T4). Findings. An analysis of variance results indicated significant improvements in powered mobility skills (F(1,22) = 56.61, p < 0.001, η²_p = 0.74) and functional mobility goals (F(1,58) = 80.17, p < 0.001, η²_p = 0.74), with 70% of goals achieved postintervention. A descriptive analysis revealed three learning profiles. Implications. This study provides initial evidence supporting the effectiveness of Power Fun as an intervention promoting powered mobility for children with severe CP, across a range of abilities.

Wheeled Mobility Use on Accessible Fixed-Route Transit: A Field Study in Environmental Docility

Multiple field studies provide qualitative accounts of usability barriers experienced by users of wheeled mobility devices on public transit. This study aimed to examine these usability barriers from the theoretical perspective of Environmental Docility by quantifying the relationship between functional capabilities of wheeled mobility device users and ingress-egress performance on accessible fixed-route transit vehicles in an urban setting. Twenty-eight wheeled mobility users each completed three trips on a predetermined route through the local public transit system. Ingress and egress times, user-reported usability ratings and open-ended comments were analyzed. Regression analyses indicated significant interactions between age and minimum parallel-park length on ingress and egress times. Specifically, lower functional capability reflected in older age and less maneuvering ability predicted decreased performance (longer ingress-egress times), indicating less adaptability to environmental demands and agreement with the Environmental Docility Hypothesis. Usability ratings and comments revealed difficulty with negotiating access ramps and turning maneuvers in the vehicle interior and in proximity to other passengers. Despite compliance with accessibility standards, current design of transit vehicles present substantial usability barriers for wheeled mobility users. Environmental Docility provides a theoretical basis to identifying modifiable factors related to person and environment for improving usability of public transit for people aging and/or with mobility impairments.

Understanding the task demands for powered wheelchair driving: a think-aloud task analysis

BACKGROUND

Powered wheelchair use promotes participation in individuals with limited mobility, however training is required for safe and effective use. There is limited evidence on the task demands of powered wheelchair use to inform an evidence-based skills training programme.

OBJECTIVE

To conduct a systematic exploration of the task demands of indoor powered wheelchair use to identify frequently used skills, abilities, and knowledge.

METHODS

We used a two-phased think aloud process to conduct a task analysis of powered wheelchair use with experienced powered wheelchair users (n = 5) and expert clinicians (n = 5). Participants completed seven indoor driving tasks while speaking aloud (concurrent think aloud) and subsequently engaged in a structured qualitative interview to discuss skills, abilities, and knowledge used across each of the seven tasks (retrospective think aloud). We used directed content analysis to map the skills and abilities to the ICF framework and conventional content analysis to develop thematic areas of knowledge used while operating a powered wheelchair.

RESULTS

One-hundred and ten (110) distinct skills and abilities were identified and mapped to the ICF; 80 in the Body Structures and Functions domain, and 30 in the Activities and Participation domain. Approximately 50% of skills and abilities were mental functions. Four thematic knowledge domains were identified: knowledge of self, environment, wheelchair, and task.

CONCLUSION

Powered wheelchair use is complex and requires a variety of skills and abilities from all areas of human functioning, in addition to a wide range of knowledge. Training programmes should address a range of areas of skill development.IMPLICATIONS FOR REHABILITATIONPowered wheelchair use is a complex skill; training should develop skills from all.Domains of the ICF, including mental and physical functions.A range of knowledge is used while operating a powered wheelchair; training programs.Should include the development and application of necessary knowledge.Clinicians may consider a range of factors when assessing suitability for powered.Wheelchair user, however should acknowledge that while the range of skills idenotified.May be useful, they may not be critical for success in powered wheelchair use.

The determinants of motorized mobility scooter driving ability after a stroke

Purpose: To investigate the determinants related to the ability to drive a motorized mobility scooter after a stroke.Method: The study was a cross-sectional study. The ability to drive a motorized mobility scooter was measured with the Power Mobility Clinical Driving Assessment. The independent variables included cognitive functions measured by the Color Trails Test and reaction time test, visual functions measured by a visual acuity test and visual field test, and motor functions measured with a dynamometer, the Box and Block Test, and the Functional Independence Measure.Results: The correlation analyses revealed that the Power Mobility Clinical Driving Assessment scores had significant correlations with reaction time (ρ = -.65, p < 0.01), binocular visual field (r = .64, p < 0.01), binocular visual acuity (r = .40, p = 0.03), and the grip strength of the unaffected hand (r = .47, p = 0.01). The multiple regression analysis indicated that reaction time, binocular visual field, and the grip strength of the unaffected hand were the most significant determinants of the ability to drive a motorized mobility scooter (R² = .76).Conclusions: The reaction time, binocular visual field, and grip strength of the unaffected hand were the most significant determinants related to the ability to drive a motorized mobility scooter after a stroke. IMPLICATIONS FOR REHABILITATIONMotorized mobility scooter driving ability for stroke patients is correlated with demographics (age, mobility scooter driving experience, time since last drive) and cognitive, visual and motor functions (reaction time, binocular visual field, visual acuity, and the grip strength of unaffected hand).Primary determinants of motorized mobility scooter driving ability for stroke patients include reaction time, binocular visual field, and grip strength of the unaffected hand.Comprehensive assessments incorporating cognitive, visual and motor functions are needed to evaluate the ability to drive a motorized mobility scooter after a stroke.

Influence of Cognitive Functioning on Powered Mobility Device Use: Protocol for a Systematic Review

Background

Power mobility devices (PMD) are critical to achieving independent mobility and social participation for many individuals who have trouble walking. Provision of PMDs is complex, with cognitive functioning expressed by clinicians as a major concern. Even if PMD use can be predicted by the level of cognitive functioning, outcome tools used to assess readiness do not consider how cognitive functioning may affect PMD use.

Objective

The specific aims of this review are to identify existing assessments used to assess cognitive functioning and PMD use, classify cognitive functions that are identified within existing assessments related to PMD use, and explore the relationships between cognitive functioning (ie, executive functions and attention) and PMD use.

Methods

A systematic review will be conducted using the electronic databases MEDLINE (Ovid), CINAHL, Embase, PsycINFO (Ovid), and Web of Science based on the concepts of PMD performance and capacity, and cognitive functioning. To be included, studies must have: a sample of PMD users (inclusive of age and diagnoses), an assessment of cognitive functioning, and an assessment of PMD capacity or performance. The International Classification of Functioning, Disability and Health will be used to classify cognitive functions. Study quality will be assessed using the Mixed Methods Appraisal Tool. Qualitative and quantitative studies will be analyzed in a complementary manner depending on their designs; a result-based convergent synthesis design will be applied.

Results

This proposed systematic review protocol has been registered in PROSPERO (CRD42019118957). It was funded by the Quebec Rehabilitation Research Network and approved on February 2019.

Conclusions

Results will inform the development of a PMD driving program that aims to enhance cognition. The results of this study will enhance understanding of the influence of cognitive functioning on PMD use and will support the clinical practice in choosing appropriate evaluative tools.

Trial Registration

PROSPERO CRD42019118957; https://www.crd.york.ac.uk/PROSPERO/display_record.php? RecordID=118957

International Registered Report Identifier (IRRID)

DERR1-10.2196/16534

Feasibility Study of a Therapeutic Mobility Summer Camp for Children with Severe Cerebral Palsy: Power Fun

Aim: Powered mobility has positive effects on development of children with limited independent locomotion, but many are deprived of this opportunity due to their limitations. This study aimed to evaluate the feasibility of Power Fun, a therapeutic summer camp, for students with severe cerebral palsy (CP).Methods: Five students with CP, ages 11-15, received personally adapted powered wheelchairs and participated daily in the camp. The camp ran five days a week during three weeks and included two mobility sessions daily. Assessments were conducted three weeks prior to the camp (T1), at baseline (T2), post-intervention (T3) and six weeks follow-up (T4). Measures used were Power Mobility Program (PMP), Assessment of Learning Power mobility use (ALP), Wheelchair Outcome Measure for Young People (WhOM-YP), Goal Attainment Scaling (GAS) and Dimensions of Mastery Questionnaire (DMQ).Results: All participants finished the camp. Outcome measures showed no change between T1-T2 but improved significantly (p<.05) after the intervention (T2-T3), and gains were maintained at T4 (Wilcoxon signed-rank test). Goals improved to slightly above the expected outcome (GAS average 0.11).Conclusions: Power Fun shows good feasibility and significant improvement in mobility skills and goals of children with severe CP. Further studies are warranted.

User-centered design of a multisensory power wheelchair simulator: towards training and rehabilitation applications

Autonomy and social inclusion can reveal themselves everyday challenges for people experiencing mobility impairments. These people can benefit from technical aids such as power wheelchairs to access mobility and overcome social exclusion. However, power wheelchair driving is a challenging task which requires good visual, cognitive and visuo-spatial abilities. Besides, a power wheelchair can cause material damage or represent a danger of injury for others or oneself if not operated safely. Therefore, training and repeated practice are mandatory to acquire safe driving skills to obtain power wheelchair prescription from therapists. However, conventional training programs may reveal themselves insufficient for some people with severe impairments. In this context, Virtual Reality offers the opportunity to design innovative learning and training programs while providing realistic wheelchair driving experience within a virtual environment. In line with this, we propose a user-centered design of a multisensory power wheelchair simulator. This simulator addresses classical virtual experience drawbacks such as cybersickness and sense of presence by combining 3D visual rendering, haptic feedback and motion cues. It relies on a modular and versatile workflow enabling not only easy interfacing with any virtual display, but also with any user interface such as wheelchair controllers or feedback devices. This paper presents the design of the first implementation as well as its first commissioning through pretests. The first setup achieves consistent and realistic behavior.

Identifying community-dwelling older adults' vision loss during mobility assessments: A scoping review

BACKGROUND.

Co-occurring mobility issues and vision loss are prevalent in older adults. Vision loss can cause ambulation difficulties and falls. Community-dwelling older adults frequently require mobility-aids assessment by occupational therapists. However, therapists often lack access to medical documentation on vision or training in vision assessment to ensure that clients have adequate vision for safe mobility-aid use.

PURPOSE.

This study aimed to identify screening and assessment approaches to identify functional vision loss to guide mobility-aid prescription.

METHOD.

A scoping review following Arksey and O'Malley's five stages was undertaken using Medline and CINAHL databases. A data-charting form was used for extraction of information about each article, including the population, vision diagnosis, and the methodology for vision screening. The data regarding vision loss and mobility of older adults were summarized for each article.

FINDINGS.

Twenty-three papers were included in the study, describing screening questions and questionnaires or assessment tools to screen for vision loss in community settings.

IMPLICATIONS.

The various tools identified can better prepare therapists to prescribe mobility aids appropriate for seniors' level of functional vision and to refer clients for further assessment and intervention if warranted.

A scoping review of powered wheelchair driving tasks and performance-based outcomes

Introduction: Wheelchairs and scooters promote participation and have positive effects on quality of life. However, powered wheelchairs (PW) use can be challenging and can pose safety concerns. Adequate PW assessment and training is important. There is a wide variety of tasks and PW driving assessment measures used for training and assessing PW driving ability in the literature and little consensus as to which tasks and outcomes are the most relevant. A scoping review of the literature was performed in order to characterize this extensive variety of tasks and performance-based outcomes used for training and assessing PW skills.Methods: A search of the literature was conducted in January 2017. Four databases were searched: CINAHL, Embase, PsycInfo and Medline. Articles were included if they contained at least one PW driving task.Results: 827 articles were screened and 48 articles were retained. PW driving tasks from each article were identified and categorized in terms of the environment in which they were performed: Driving in a controlled environment, ecological driving tasks, 2D virtual environment (VE) tasks, 3D VE tasks. The assessment measures formed a separate category. Subjective and objective performance-based outcomes related to PW driving were also identified and grouped into outcomes assessing speed and outcomes assessing accuracy.Conclusion: This scoping review provides an overview of tasks and performance outcomes used in the literature when training and assessing PW skills. The results of this review could guide future research when choosing appropriate tasks and performance outcomes for PW driving ability.Implications for rehabilitationThere is wide variety of tasks and performance-based outcomes for PW driving.Results showed that available assessment measures are not commonly used in research and that tasks used often lacked consistency across studies.New methods to measure the interaction of speed and accuracy are needed.The contents of this review could be used by researchers as a starting point when designing a PW task and selecting appropriate performance-based outcomes.

Design of an immersive simulator for assisted power wheelchair driving

Driving a power wheelchair is a difficult and complex visual-cognitive task. As a result, some people with visual and/or cognitive disabilities cannot access the benefits of a power wheelchair because their impairments prevent them from driving safely. In order to improve their access to mobility, we have previously designed a semi-autonomous assistive wheelchair system which progressively corrects the trajectory as the user manually drives the wheelchair and smoothly avoids obstacles. Developing and testing such systems for wheelchair driving assistance requires a significant amount of material resources and clinician time. With Virtual Reality technology, prototypes can be developed and tested in a risk-free and highly flexible Virtual Environment before equipping and testing a physical prototype. Additionally, users can "virtually" test and train more easily during the development process. In this paper, we introduce a power wheelchair driving simulator allowing the user to navigate with a standard wheelchair in an immersive 3D Virtual Environment. The simulation framework is designed to be flexible so that we can use different control inputs. In order to validate the framework, we first performed tests on the simulator with able-bodied participants during which the user's Quality of Experience (QoE) was assessed through a set of questionnaires. Results show that the simulator is a promising tool for future works as it generates a good sense of presence and requires rather low cognitive effort from users.

Joystick-controlled video console game practice for developing power wheelchairs users' indoor driving skills

[Purpose] This study aimed to determine the effectiveness of joystick-controlled video console games in enhancing subjects’ ability to control power wheelchairs. [Subjects and Methods] Twenty healthy young adults without prior experience of driving power wheelchairs were recruited. Four commercially available video games were used as training programs to practice joystick control in catching falling objects, crossing a river, tracing the route while floating on a river, and navigating through a garden maze. An indoor power wheelchair driving test, including straight lines, and right and left turns, was completed before and after the video game practice, during which electromyographic signals of the upper limbs were recorded. The paired t-test was used to compare the differences in driving performance and muscle activities before and after the intervention. [Results] Following the video game intervention, participants took significantly less time to complete the course, with less lateral deviation when turning the indoor power wheelchair. However, muscle activation in the upper limbs was not significantly affected. [Conclusion] This study demonstrates the feasibility of using joystick-controlled commercial video games to train individuals in the control of indoor power wheelchairs.

A participatory approach to develop the Power Mobility Screening Tool and the Power Mobility Clinical Driving Assessment tool

The electric powered wheelchair (EPW) is an indispensable assistive device that increases participation among individuals with disabilities. However, due to lack of standardized assessment tools, developing evidence based training protocols for EPW users to improve driving skills has been a challenge. In this study, we adopt the principles of participatory research and employ qualitative methods to develop the Power Mobility Screening Tool (PMST) and Power Mobility Clinical Driving Assessment (PMCDA). Qualitative data from professional experts and expert EPW users who participated in a focus group and a discussion forum were used to establish content validity of the PMCDA and the PMST. These tools collectively could assess a user's current level of bodily function and their current EPW driving capacity. Further multicenter studies are necessary to evaluate the psychometric properties of these tests and develop EPW driving training protocols based on these assessment tools.

Assessment of wheelchair driving performance in a virtual reality-based simulator

OBJECTIVE

To develop a virtual reality (VR)-based simulator that can assist clinicians in performing standardized wheelchair driving assessments.

DESIGN

A completely within-subjects repeated measures design.

METHODS

Participants drove their wheelchairs along a virtual driving circuit modeled after the Power Mobility Road Test (PMRT) and in a hallway with decreasing width. The virtual simulator was displayed on computer screen and VR screens and participants interacted with it using a set of instrumented rollers and a wheelchair joystick. Driving performances of participants were estimated and compared using quantitative metrics from the simulator. Qualitative ratings from two experienced clinicians were used to estimate intra- and inter-rater reliability.

RESULTS

Ten regular wheelchair users (seven men, three women; mean age ± SD, 39.5 ± 15.39 years) participated. The virtual PMRT scores from the two clinicians show high inter-rater reliability (78-90%) and high intra-rater reliability (71-90%) for all test conditions. More research is required to explore user preferences and effectiveness of the two control methods (rollers and mathematical model) and the display screens.

CONCLUSIONS

The virtual driving simulator seems to be a promising tool for wheelchair driving assessment that clinicians can use to supplement their real-world evaluations.

Neuropsychological predictors of powered wheelchair use: a prospective follow-up study

Objectives: To investigate (1) rates of powered wheelchair use and level of user-rated functional performance at one-month follow-up, and (2) whether psychological variables were prospectively predictive of outcome.

Design: Prospective follow-up study.

Setting: UK hospital-based regional rehabilitation and mobility centre.

Participants: Volunteer adults with impaired mobility. Of 155 approached, 103 had baseline assessments. Of these, 81 (79%) provided outcome data. Mean age was 65.6 years (SD = 13.5); 55% were male.

Main outcome measures: Rate of day-to-day powerchair use, and users' perceptions of how well the powerchair allowed them to perform functional tasks.

Results: Among those with indoor-only chairs, 48% were 'less frequent' users; this rose to 72% among those with indoor/outdoor chairs. Excluding environmental reasons, rate of indoor use was predicted by baseline measures of verbal recall (P<0.001), figure copying (P=0.003) and global cognition (P=0.021). Among those with indoor/outdoor chairs, total rate of use was predicted by verbal recall (P= 0.001). Participants reported that the powerchair was effective in meeting their functional needs.

Conclusions: Powered wheelchair use was predicted by cognitive measures. Rates of use were relatively low, despite users' reports that the powerchair facilitated their everyday functioning well.