The Six Spot Step Test: Evaluating the Benefits of an Understudied Ambulation Test in Multiple Sclerosis

Background: The Six Spot Step Test (SSST) is a quantitative test of ambulation with components of coordination, dynamic balance, and lower limb function in individuals with multiple sclerosis (MS). The SSST has unique characteristics that are not replicated in other tests; it requires individuals to stop and start while ambulating, shift weight, and kick weighted objects from six “spot” targets. The SSST is clinically feasible because it is easy to systematically administer and requires only a small amount of space to perform. The SSST was initially validated with the Timed 25 foot Walk (T25W) and found to have less of a floor effect than the T25W, but its relationship to clinical walking measures that include turning and longer distances has not been examined. 

Objectives: To explore the relationship and potential concurrent validity of the SSST with the Timed Up and Go (TUG) and the Two Minute Walk Test (2MWT) in MS.

Methods: Sixteen individuals with relapsing remitting MS (average age: 51.2±9.5 years; symptom duration: 14±9.7 years; EDSS: 3.9±1.4; 9 females, 7 males) participated in the study.  In a single session, individuals performed the TUG, T25W, 2MWT and ZenoMat gait assessment.  Pearson’s correlation coefficients were used to assess statistical significance.

Results: The SSST is strongly related to both the TUG (r=0.7518) and 2MWT (r=0.8051) and less so with the T25W (r=0.6991). The TUG includes a functional transfer (sit to stand) and turning, while the 2MWT includes turning and walking endurance. Both of these tests require more challenging and real-world elements than walking alone, as on the T25W. 

Conclusions: The SSST demonstrates concurrent validity with both the TUG and the 2MWT in our cohort of individuals with MS. The SSST captures an important element of MS disability by examining walking in a more comprehensive manner than the other three walking tests. Furthermore, the SSST requires minimal training to administer and may be a time-efficient measure of real-life functional activities that would be useful in large clinical trials. The SSST may be a relevant alternative to the TUG and 2MWT in outcome measure assessment for individuals with MS. This data is part of a larger study and data collection is ongoing; future analysis will examine the relationship of the SSST to falls and spatiotemporal measures of walking.