The MAT-sf: clinical relevance and validity

The measurement of mobility is essential to both aging research and clinical practice. A newly developed self-report measure of mobility, the mobility assessment tool-short form (MAT-sf), uses video animations to improve measurement accuracy/precision. Using a large baseline data set, we recalibrated the items, evaluated the extent to which older patients' self-efficacy (i.e., confidence) for walking was related to MAT-sf scores beyond their actual 400-m walk time, and assessed the relationship of the MAT-sf with body mass index and other clinical variables.

The analyses employed baseline data from the Lifestyle Interventions and Independence for Elders Study.

Item recalibration demonstrated that the MAT-sf scoring algorithm was robust. In an analysis with 400-m walk time and self-efficacy regressed on the MAT-sf, both variables shared unique variance with the MAT-sf (p < .001). The MAT-sf was inversely related to several comorbidities, most notably hypertension and arthritis (p < .001), and scores were lowest when body mass index ≥ 35 kg/m(2). Finally, MAT-sf scores were directly related to Short Physical Performance Battery scores, inversely related to difficulty with activities of daily living (p < .001) and higher for men than for women (p < .001).

The findings extend the validity and clinical utility of this innovative tool for assessing self-reported mobility in older adults. Longitudinal data on the MAT-sf from the Lifestyle Interventions and Independence for Elders Study will enable us to evaluate the relative contributions of self-report and performance-based measures of mobility on important health outcomes.