Utility of the Six-Spot Step Test as a Measure of Walking Performance in Ambulatory Individuals With Multiple Sclerosis

Objective: To examine the concurrent validity of the Six-Spot Step Test (SSST) with clinical measures of walking and spatiotemporal measures of gait in multiple sclerosis (MS), and to understand the utility of the SSST in individuals with both low and high levels of disability.

Design: Cross-sectional study.

Setting: Laboratory.

Participants: Individuals with relapsing-remitting MS (N=29).

Interventions: Not applicable.

Main outcome measures: In a single visit, demographic information (age, sex, Expanded Disability Status Scale [EDSS], symptom duration) and functional measures (SSST, timed Up and Go [TUG] test, timed 25-foot walk [T25FW] test, spatiotemporal measures of walking) were collected.

Results: The SSST demonstrates concurrent validity with the TUG test, T25FW test, and 2-minute walk test (2MWT) (P≤.0002). Both spatial and temporal measures of gait are significantly related to SSST performance (P<.004). In individuals with lower disability (EDSS score 1-3.5), the SSST remains strongly related to the TUG test and T25FW test performances, whereas it fails to relate to any other measures. However, in the higher disability group (EDSS score 4-6), the SSST is significantly related to the TUG test, T25FW test, 2MWT, walk velocity, and both temporal and spatial measures of gait.

Conclusions: The SSST is an alternative test for lower-extremity function in the clinical setting that may useful in both higher and lower EDSS groups. The SSST requires minimal training to administer and may be a time-efficient measure of real-life functional performance that would be useful in large clinical trials.