Discriminatory validity of the Aspects of Wheelchair Mobility Test as demonstrated by a comparison of four wheelchair types designed for use in low-resource areas

The Wheelchair Propulsion Wheel Rotation Angle Function Symmetry in the Propelling Phase: Motion Capture Research and a Mathematical Model

The movement of a wheelchair with manual propulsion depends on the kinematics of the human body and the forces exerted by the muscles. To design innovative wheelchair propulsion systems, the biomechanical parameters resulting from human interaction in this anthropotechnical system must be formalised. The research objectives were thus adopted: an analysis of the propulsion wheel angle of rotation resulting from the hand movement’s trajectory and the mathematical formalisation of the propulsion wheel angle of rotation described as a function of the propelling phase’s duration. The research was carried out using three variants of manually propelled wheelchairs on a group of 10 patients representing the same group (C50) of anthropometric dimensions. The research demonstrated that the function of the propulsion wheel angle of rotation shows the features of central symmetry occurring at an angle of rotation of φ 52° and a propelling phase duration of 58%. Moreover, the measurements were averaged and a mathematical model of the propulsion wheel rotation function during the propulsion phase was developed, depending on the percentage of duration.

Development of the Wheelchair Interface Questionnaire and initial face and content validity

Background

Because resources are limited in low- and middle-income countries (LMIC), the development of outcome measures is of interest. Wheelchair outcome measures are useful to support evidence-based practice in wheelchair provision.

Objectives

The Wheelchair Interface Questionnaire (WIQ) is being developed to provide a professional perspective on the quality of the interface between a wheelchair and its user. This article discusses the development of the WIQ and its face and content validity.

Method

During field studies in Kenya, we sought to include professional report data on the wheelchair–user interface that could be analysed to inform design changes. None of the existing measures was focused on the interface between users and their wheelchairs. The WIQ was developed to meet this need. To investigate face and content validity, 24 experienced wheelchair professionals participated in a study that included two rounds of an online survey and a focus group in Kenya.

Results

Responses were categorised by topic and the WIQ was modified following each iteration. Participants affirmed the usefulness of a brief professional report measure to provide a snapshot of the user–wheelchair interface. Participants emphasised the importance of brevity, wide applicability and provision of specific feedback for wheelchair modification or design changes. The focus group agreed that the final version provided useful data and was applicable to virtually all wheelchair users in LMIC.

Conclusion

These preliminary studies indicate initial face and content validity of the WIQ as a method for providing a professional perspective on the interface between a user and his or her wheelchair.

Keywords

Outcome measure; wheelchair assessment; user–wheelchair interface; wheelchair appropriateness; professional report.

Editorial

No abstract available.

Test-retest reliability and construct validity of the Aspects of Wheelchair Mobility Test as a measure of the mobility of wheelchair users

Background

The Aspects of Wheelchair Mobility Test (AWMT) was developed for use in a repeated measures format to provide comparative effectiveness data on mobility facilitated by different wheelchair types. It has been used in preliminary studies to compare the mobility of wheelchairs designed for low-resource areas and is intended to be simple and flexible enough so as to be used in low-technology settings. However, to reliably compare the impact of different types of wheelchairs on the mobility of users, a measure must first be a reliable and valid measure of mobility.

Methods

This study investigated the test–retest reliability and concurrent validity for the AWMT 2.0 as a measure of mobility. For reliability testing, participants in a low-resource setting completed the tests twice in their own wheelchairs at least one week apart. For concurrent validity, participants also completed the Wheelchair Skills Test Questionnaire (WST-Q), a related but not identical validated assessment tool.

Results

Concurrent validity was indicated by a significant positive correlation with an r value of 0.7 between the WST-Q capacity score and the AWMT 2.0 score. Test–retest reliability was confirmed by an intraclass correlation coefficient greater than 0.7 between the two trials.

Conclusion

Results support the preliminary reliability and validity of the AWMT 2.0, supporting its effectiveness in comparing the mobility provided by different wheelchair types. This information can be used to enable effective use of limited funds for wheelchair selection at individual and organisational scales.