Community use of a pushrim activated power-assisted wheelchair by an individual with facioscapulohumeral muscular dystrophy

Perception of autonomy among people who use wheeled mobility assistive devices: Dependence on the type of wheeled assistive technology

We evaluated perceived autonomy among users of different types of wheeled mobility assistive devices (WMADs) across five environments and identified the effect on user autonomy due to specific device characteristics. A study-specific questionnaire was used to assess satisfaction with autonomy of WMAD users in the Home, Buildings Outside of the Home, Outdoor Built, Outdoor Natural Environment, and Transportation. For each environment, 15 contextual factors were rated for their impact on participants' autonomy. Our results revealed that manual wheelchair with add-on (MWC+AO) users had higher overall satisfaction with their autonomy compared to other WMAD users. MWC+AO users reported higher satisfaction with autonomy due to their health conditions compared to other WMAD users across all environments. In Outdoor Natural Environments, MWC+AO users had the highest satisfaction with autonomy across all factors except for negotiating hills. When performing activities in Buildings, MWC users with and without add-ons reported higher satisfaction for all factors compared to power wheelchair users, except for maneuverability on different surfaces. Satisfaction with autonomy regarding contextual factors varied among WMAD users, however, MWC+AO(s) appeared to provide a more balanced sense of autonomy across most factors and environments. More in-depth investigations are required to evaluate impacts of add-on use on autonomy.

A Comparison Between Conventional and User-Intention-Based Adaptive Pushrim-Activated Power-Assisted Wheelchairs

Pushrim-activated power-assisted wheel (PAPAW) users ideally require different levels of assistance depending on activity and preference. Therefore, it is important to design and develop adaptive PAPAW controllers to account for these differences. The main objective of this work was to integrate a user intention estimation framework into a PAPAW and develop personalized adaptive controllers. We performed experiments to gather kinetics of wheelchair propulsion for a variety of daily life wheelchair activities. The propulsion characteristics (i.e., pushrim forces) were used to train intention estimation models and characterize implicit user intentions when performing daily life wheelchair maneuvers. These intentions included moving straight forward, performing a right/left turn, and braking. The intention estimation framework, based on random forest classification algorithms and kinetic features, was implemented and tested in our laboratory-developed PAPAW. This computationally efficient framework was successfully implemented and tested for each participant in real-time. Our results revealed that the real-time user intention predictions were similar to the offline models. The power-assist ratio of each wheel was adjusted based on which user intention was identified. Data collected from four participants provided evidence regarding the effectiveness of using adaptive intention-based controllers. For instance, the propulsion effort was significantly reduced when using an adaptive PAPAW controller. Subjective views of participants regarding the workload of wheelchair propulsion (e.g., physical/cognitive effort) were also gathered. Our findings suggest that rankings of different controllers varied among different participants and across different wheelchair maneuvers, indicating the need for customized adaptive controllers to fit different users' activities and preferences.

Perceptions of power-assist devices: interviews with manual wheelchair users

PURPOSE

The study had three main objectives. (1) To investigate the perceived impact of power-assist devices (PADs) on manual wheelchair (MWC) user mobility. (2) To compare perceptions about different types of PADs. (3) To identify preferred features and design characteristics of PADs.

METHODS

Semi-structured interviews were conducted with community-dwelling MWC users aged 31 years and older, with at least 2.5 years of experience using an MWC independently (n = 16). Data were thematically analysed using an inductive approach.

RESULTS

Two main themes related to participants' perceptions about the effects of PAD use were identified: (1) "Expanding my world", which illustrated the perceived benefits of using PADs (e.g., gaining a sense of autonomy and access to new environments, maintaining physical health) and (2) "Falling short", which described challenges with PADs (e.g., safety, reliability and portability issues). Participants also identified strengths and limitations of different types of PADs that were mainly related to specific user-device and device-environment interactions as well as various functional characteristics. Moreover, participants outlined their priorities for future PAD design, including improving controllability, customizability and affordability of these devices.

CONCLUSIONS

Participants' perceptions about PADs varied across different types of devices and in different contexts. However, PADs were generally perceived as enhancing the capabilities of MWCs. Our findings provide insight into the factors that can be considered when selecting a PAD and can inform the development of future PADs that are better equipped to overcome challenges that MWC users frequently encounter.Implications for RehabilitationPower-assist devices (PADs) for manual wheelchairs (MWCs) have the potential to improve the mobility, community participation and well-being of users.Some of the existing PADs have safety and reliability issues that affect their performance and limit their use by MWC users.The three types of PADs (front-mounted attachments, rear-mounted attachments, powered wheels) offer different types of assistance that can benefit users with various capabilities.

Development of A Learning-Based Terrain Classification Framework for Pushrim-Activated Power-Assisted Wheelchairs

Pushrim-activated power-assisted wheels (PAPAWs) are assistive technologies that provide on-demand torque assistance to wheelchair users. Although the available power can reduce the physical load of wheelchair propulsion, it may also cause maneuverability and controllability issues. Commercially-available PAPAW controllers are insensitive to environmental changes, leading to inefficient and/or unsafe wheelchair movements. In this regard, adaptive velocity/torque control strategies could be employed to improve safety and stability. To investigate this objective, we propose a context-aware sensory framework to recognize terrain conditions. In this paper, we present a learning-based terrain classification framework for PAPAWs. Study participants performed various maneuvers consisting of common daily-life wheelchair propulsion routines on different indoor and outdoor terrains. Relevant features from wheelchair frame-mounted gyroscope and accelerometer measurements were extracted and used to train and test the proposed classifiers. Our findings revealed that a one-stage multi-label classification framework has a higher accuracy performance compared to a two-stage classification pipeline with an indoor-outdoor classification in the first stage. We also found that, on average, outdoor terrains can be classified with higher accuracy (90%) compared to indoor terrains (65%). This framework can be used for real-time terrain classification applications and provide the required information for an adaptive velocity/torque controller design.

Exercise Intensity During Power Wheelchair Soccer

OBJECTIVE

To determine exercise intensity during power wheelchair soccer among a sample of persons with mobility impairments.

DESIGN

Cross-sectional descriptive.

SETTING

On-site training facilities of multiple power wheelchair soccer teams.

PARTICIPANTS

Participants with severe mobility impairments (N=30) (mean ± SD, age: 29.40±15.51y, body mass index: 24.11±6.47kg/m², power soccer experience: 7.91±3.93y, disability sport experience: 12.44±9.73y) were recruited from multiple power wheelchair soccer teams.

INTERVENTIONS

Portable metabolic carts were used to collect oxygen consumption (V˙o₂) data during resting and game play conditions.

MAIN OUTCOME MEASURES

Average V˙o₂ (expressed in metabolic equivalent tasks [METs]) during resting and game play conditions and rating of perceived exertion for game play.

RESULTS

V˙o₂ increased from 1.35±0.47 METs at rest to 1.81±0.65 METs during game play. This 34% increase in exercise intensity was significant (P<.01) and supported by a mean perceived exertion score of approximately 13 (somewhat hard).

CONCLUSIONS

Although not able to sustain an intensity associated with reduced secondary disease risk (ie, 3 METs), the documented light-intensity exercise in the current study surpassed an intensity threshold associated with improved functional capacity and performance of daily living activities (ie, 1.5 METs).

Experiences with Using a Pushrim-Activated Power-Assisted Wheelchair for Community-Based Occupations: A Qualitative Exploration

Background. Occupational therapists strive to engage individuals in occupation and enhance community access through wheelchair prescription. Previous research with pushrim-activated, power-assisted wheelchairs identifies a reduction in the physical demands of manual wheelchair propulsion but limited evidence exists regarding user evaluation in context. Purpose. This study explored the experience of using a power-assisted wheelchair in the community. Methods. Eight individuals who used both a power and manual device participated in focus groups after trialing a power-assist wheelchair for three weeks. Data were analyzed using a qualitative description approach. Findings. Three themes emerged from our analysis: relative advantages and disadvantages; environmental factors that affect accessibility; and evaluation of mobility device. Implications. Participants perceived the power-assist as improving performance and accessibility compared with the manual wheelchair, increasing the potential scope of occupations and environments, but not replacing their power mobility device. Sufficient time for adjustment of both user and device was important.

Use of power assist wheels results in increased distance traveled compared with conventional manual wheeling

OBJECTIVE

To evaluate the impact of power assist wheels on the distance traveled by manual wheelchair users and analyze potential cofactors in the magnitude of response and to test the hypothesis that wheelers would travel significantly further with power assist wheels.

DESIGN

A 16-wk A (Preintervention)-B (Intervention)-A (Postintervention) repeated measures design. Seven women and 13 men (age, 43 +/- 15 yrs) full-time wheelers participated. During the pre- and postintervention phases (4 wks each), participants used their own unaltered manual wheelchairs. During the 8-wk intervention phase, the manual wheels were replaced with power assist wheels. Daily distance was measured with bicycle-style odometers. A composite score of laboratory wheelchair tasks was used to classify wheelchair performance. Mixed model repeated measures analysis of variance analyzed changes across phases of the trial. A post hoc analysis tabulated the amount of days wheelers exceeded their individual daily averages in each phase by two SDs.

RESULTS

Wheelers traveled significantly greater distances during the intervention phase compared with pre- or postintervention phases regardless of baseline wheelchair performance. Wheelers who demonstrated higher baseline wheelchair performance traveled lesser average distances in the first 2 wks after receiving power assist wheels than in the subsequent 6 wks. Wheelers exceeded their individual daily averages per phase on a significantly greater number of days during the intervention phase.

CONCLUSIONS

Power assist wheels enabled wheelers to travel farther and to travel beyond their usual distances on more days. Further studies may be strengthened by taking into account the 2-wk "adjustment phase" for power assist wheels.