MARS Properties

Reliability

The MARS has been subjected to 2 large sample studies of inter-rater reliability. The first (Whyte, Hart, Bode & Malec, 2003) compared ratings of patients’ Occupational Therapists (OTs) and Physical Therapists (PTs) done independently over the same 3-day window. Agreement was good (Pearson r = .64). When there were disagreements, OTs tended to rate attention as slightly worse than PTs. The second study (Whyte, Hart, Ellis & Chervoneva, 2008) compared ratings across 4 disciplines: OT, PT, Speech Therapy (ST) and Nursing, using ratings conducted both early and late in the inpatient rehabilitation stay. Agreement across disciplines was fairly robust, with Nursing showing somewhat lower concordance with therapy disciplines. This was interpreted as possibly relating to the less structured and more variable observations available to nursing vs. therapy staff on an inpatient rehabilitation unit.

Validity

Hart, Whyte, Ellis, & Chervoneva (2009) showed that total scores on the MARS administered to rehabilitation inpatients in the subacute phase of TBI (1) were more strongly correlated to concurrent measures thought to assess attention (e.g., (Digit Span) than those thought to be less demanding of attention (e.g., grip strength); (2) were more strongly correlated to Cognitive than Motor FIM scores; and (3) predicted 1-year outcomes of TBI (Disability Rating Scale scores) better than a battery of psychometric measures of attention administered concurrently with the MARS. These findings provide support for the MARS as a measure of cognitive function, specifically attention, which performs well as a predictor of outcome.

The MARS is highly sensitive to the effects of “natural recovery plus rehabilitation” in the subacute phase of TBI, i.e., MARS scores are significantly higher near rehabilitation discharge compared to rehabilitation admission several weeks earlier (Whyte et al., 2008). However, its sensitivity to treatments specifically targeting attention remains to be determined. The MARS did not discriminate groups of inpatients with TBI with attention deficits who had received a 3-day course of methylphenidate or placebo (Hart et al., 2009). However, it was unclear whether the MARS was insensitive or the treatment was not sufficiently powerful—e.g., too short, not strong enough to add-on to natural recovery—to show an effect.