Reliability, convergent validity and applicability of the Assistive Technology Outcome Profile for Mobility for middle-aged and older power wheelchair users.

Abstract

The Assistive Technology Outcome Profile for Mobility (ATOP/M) was designed to isolate the impact of mobility assistive technology on perceived difficulty with activity and participation. The study objectives were to examine its measurement properties (test-retest reliability and convergent validity) and applicability for middle-aged and older power wheelchair (PWC) users. Four ATOP/M subscales were administered using computer adaptive testing (activity with mobility device, activity without mobility device, participation with mobility device, participation without mobility device). Test-retest reliability (4-wk interval), convergent validity (a priori hypothesis testing of correlations with participation (Late-life Disability Instrument) and mobility (Life-space Assessment)) and applicability (respondent burden, distributions) were examined with 116 PWC users between 50 and 85years of age presenting with a variety of diagnoses. When using powered mobility, perceived difficulty with activity and participation scores were similar to the general population of mobility devices users (T-score range 46.3-53.7), while activity and participation were significantly lower without mobility devices (T-score range 35.3-39.4). Test-retest reliability intra-class coefficients of the four subscales ranged between 0.82 and 0.91, and convergent validity was supported by moderate correlations (r=0.35-0.47). Respondent burden was higher for the without devices subscales and none of the subscales had significant floor/ceiling effects. Our results provide support for reliability and convergent validity of the ATOP/M for PWC users. Specific strategies were recommended to optimise applicability with this population such as administration guidelines for reframing the without device scale and timing of data collection.