Reliability and Responsiveness of the High-level Mobility Assessment Tool (HiMAT)
High-level mobility is poorly measured following traumatic brain injury (TBI) despite its importance for social, leisure and sporting activities and quality of life in general. The development of the high-level mobility assessment tool (HiMAT) has been previously reported. This study investigates the concurrent validity, magnitude of ceiling effect and reliability of the HiMAT. Data were collected from 103 TBI patients, aged 14-60, on the HiMAT. Data on the gross function component of the Rivermead Mobility Assessement (RMA) and motor FIM were also collected to investigate concurrent validity and presence of a ceiling effect. The correlation between the HiMAT and motor FIM was poor (r = .53, p < .01), largely due to a substantial ceiling effect of the motor FIM. The correlation between the HiMAT and gross function RMA was good (r = .87, p < .01), but the gross function RMA was also susceptible to a ceiling effect with 51.5% achieving the maximal score. Inter-rater reliability for the HiMAT was very high (ICC = .99). Retest reliability was investigated using three methods. A correlation was performed and found to be very high (ICC = .99). A paired t test showed a significant but small systematic improvement of 1.0 point (t =3.82, p< .001) had occurred. The minimal detectable change (MDC) was calculated to be +/- 3 points. No participant improved by more than the MDC. The HiMAT is a reliable tool that quantifies mobility limitations responsible for participation restrictions and measures mobility better than any existing scales used in TBI.