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Evaluation of an intelligent wheelchair system for older adults with cognitive impairments.

How TV, Wang RH, Mihailidis A - J Neuroeng Rehabil (2013)

Bottom Line: Measurements of safety and usability were taken and compared between the two phases.However, the objective performance (time to complete course) of users navigating their environment did not improve with the IWS.This study shows the efficacy of the IWS in performing with a potential environment of use, and benefiting members of its desired user population to increase safety and lower perceived demands of powered wheelchair driving.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto ON, Canada.

ABSTRACT

Background: Older adults are the most prevalent wheelchair users in Canada. Yet, cognitive impairments may prevent an older adult from being allowed to use a powered wheelchair due to safety and usability concerns. To address this issue, an add-on Intelligent Wheelchair System (IWS) was developed to help older adults with cognitive impairments drive a powered wheelchair safely and effectively. When attached to a powered wheelchair, the IWS adds a vision-based anti-collision feature that prevents the wheelchair from hitting obstacles and a navigation assistance feature that plays audio prompts to help users manoeuvre around obstacles.

Methods: A two stage evaluation was conducted to test the efficacy of the IWS. Stage One: Environment of Use - the IWS's anti-collision and navigation features were evaluated against objects found in a long-term care facility. Six different collision scenarios (wall, walker, cane, no object, moving and stationary person) and three different navigation scenarios (object on left, object on right, and no object) were performed. Signal detection theory was used to categorize the response of the system in each scenario. Stage Two: User Trials - single-subject research design was used to evaluate the impact of the IWS on older adults with cognitive impairment. Participants were asked to drive a powered wheelchair through a structured obstacle course in two phases: 1) with the IWS and 2) without the IWS. Measurements of safety and usability were taken and compared between the two phases. Visual analysis and phase averages were used to analyze the single-subject data.

Results: Stage One: The IWS performed correctly for all environmental anti-collision and navigation scenarios. Stage Two: Two participants completed the trials. The IWS was able to limit the number of collisions that occurred with a powered wheelchair and lower the perceived workload for driving a powered wheelchair. However, the objective performance (time to complete course) of users navigating their environment did not improve with the IWS.

Conclusions: This study shows the efficacy of the IWS in performing with a potential environment of use, and benefiting members of its desired user population to increase safety and lower perceived demands of powered wheelchair driving.

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Related in: MedlinePlus

Time taken to complete the obstacle course for participants in each run.
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Figure 9: Time taken to complete the obstacle course for participants in each run.

Mentions: For objective measures: Figure 7, shows the movement pass rates totalled across each of the participant’s phases. A change in pass rate occurred between the phases for participant 1’s left turn (80% to 70%), right turn (10% to 100%), straight path (60% to 80%), and stopping (80% to 100%); and participant 2’s left turn (90% to 100%), and straight path (70% to 100%). The number of FOV collisions and the time to complete each run are shown in Figures 8 and 9 respectively for both participants. Participant 1’s FOV collisions had a sharp discontinuity when the IWS was introduced (one of the criteria to support the impact of an intervention in single-subject research [23]), and both participants maintained a lower magnitude of collisions during the IWS phase. It is noted that a peak in collisions occurred in both participant 1 and 2’s run 4. For participant 1’s time to completion, there was no sharp discontinuity between the phases, and the average in each phase is similar; whereas participant 2’s time to completion shows a rise in time when the IWS was introduced, and also a trend of decreasing time in each phase. Both participants did not reach a high adherence to audio prompts: participant 1 had an adherence of 76.5% and participant 2 had an adherence of 56.4%.


Evaluation of an intelligent wheelchair system for older adults with cognitive impairments.

How TV, Wang RH, Mihailidis A - J Neuroeng Rehabil (2013)

Time taken to complete the obstacle course for participants in each run.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750699&req=5

Figure 9: Time taken to complete the obstacle course for participants in each run.
Mentions: For objective measures: Figure 7, shows the movement pass rates totalled across each of the participant’s phases. A change in pass rate occurred between the phases for participant 1’s left turn (80% to 70%), right turn (10% to 100%), straight path (60% to 80%), and stopping (80% to 100%); and participant 2’s left turn (90% to 100%), and straight path (70% to 100%). The number of FOV collisions and the time to complete each run are shown in Figures 8 and 9 respectively for both participants. Participant 1’s FOV collisions had a sharp discontinuity when the IWS was introduced (one of the criteria to support the impact of an intervention in single-subject research [23]), and both participants maintained a lower magnitude of collisions during the IWS phase. It is noted that a peak in collisions occurred in both participant 1 and 2’s run 4. For participant 1’s time to completion, there was no sharp discontinuity between the phases, and the average in each phase is similar; whereas participant 2’s time to completion shows a rise in time when the IWS was introduced, and also a trend of decreasing time in each phase. Both participants did not reach a high adherence to audio prompts: participant 1 had an adherence of 76.5% and participant 2 had an adherence of 56.4%.

Bottom Line: Measurements of safety and usability were taken and compared between the two phases.However, the objective performance (time to complete course) of users navigating their environment did not improve with the IWS.This study shows the efficacy of the IWS in performing with a potential environment of use, and benefiting members of its desired user population to increase safety and lower perceived demands of powered wheelchair driving.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto ON, Canada.

ABSTRACT

Background: Older adults are the most prevalent wheelchair users in Canada. Yet, cognitive impairments may prevent an older adult from being allowed to use a powered wheelchair due to safety and usability concerns. To address this issue, an add-on Intelligent Wheelchair System (IWS) was developed to help older adults with cognitive impairments drive a powered wheelchair safely and effectively. When attached to a powered wheelchair, the IWS adds a vision-based anti-collision feature that prevents the wheelchair from hitting obstacles and a navigation assistance feature that plays audio prompts to help users manoeuvre around obstacles.

Methods: A two stage evaluation was conducted to test the efficacy of the IWS. Stage One: Environment of Use - the IWS's anti-collision and navigation features were evaluated against objects found in a long-term care facility. Six different collision scenarios (wall, walker, cane, no object, moving and stationary person) and three different navigation scenarios (object on left, object on right, and no object) were performed. Signal detection theory was used to categorize the response of the system in each scenario. Stage Two: User Trials - single-subject research design was used to evaluate the impact of the IWS on older adults with cognitive impairment. Participants were asked to drive a powered wheelchair through a structured obstacle course in two phases: 1) with the IWS and 2) without the IWS. Measurements of safety and usability were taken and compared between the two phases. Visual analysis and phase averages were used to analyze the single-subject data.

Results: Stage One: The IWS performed correctly for all environmental anti-collision and navigation scenarios. Stage Two: Two participants completed the trials. The IWS was able to limit the number of collisions that occurred with a powered wheelchair and lower the perceived workload for driving a powered wheelchair. However, the objective performance (time to complete course) of users navigating their environment did not improve with the IWS.

Conclusions: This study shows the efficacy of the IWS in performing with a potential environment of use, and benefiting members of its desired user population to increase safety and lower perceived demands of powered wheelchair driving.

Show MeSH
Related in: MedlinePlus