Establishing the Reliability of The Step Test Evaluation of Performance on Stairs (STEPS) in Multiple Sclerosis

Objective To establish the inter- and intra-rater reliability of The Step Test Evaluation of Performance on Stairs (STEPS) for people with Multiple Sclerosis (PwMS) and examine its relation to clinical mobility measures, cognition, and activity levels. Design and Setting STEPS performance was rated by three raters at the initial visit. Two raters observed the STEPS performance via videotape at the initial visit and then one week later. Participants also completed in lab clinical mobility tests and cognitive assessments at their initial visit. Activity levels were tracked for the subsequent six months. Participants In total, 23 people with relapsing-remitting MS. Interventions Not applicable Main Outcome Measure(s) Intraclass correlation coefficients (ICCs) were used to assess intrarater and interrater reliability, while correlation analyses compared STEPS performance with cognition, clinical mobility assessments, and activity levels. The inter-rater reliability analysis amongst the three raters included scoring from only the initial evaluation. For the intra-rater reliability, two raters viewed and rated the videotaped session for each of the participants and then repeated the same process 1 week later. Results Total STEPS scores demonstrated excellent agreement by intraclass correlation coefficient for inter- (ICC = 0.97) and intra-rater reliability (ICC >0.95) and significant correlations with established clinical mobility assessments in PwMS. Better performance on STEPS was associated with information processing speed and prospective activity levels in PwMS. Conclusions Stair ambulation is a challenging task, integral for mobility and independence, therefore, having a sensitive and valid reliable assessment of stair performance is critical for PwMS. The STEPS assessment is a quick, easily administered, reliable, and valid tool for assessing stair ambulation in PwMS.