Objective: The primary objective of this study was to develop a quantitative test to assess ambulation in multiple sclerosis (MS) patients that is more accurate and sensitive than the Timed 25-foot walk (T25FW). For this purpose, we developed the Six Spot Step Test (SSST), which besides speed includes co-ordination and balance, to be a lower limb counterpart to the 9-Hole Peg Test (9HPT).
Background: The T25FW, which is the ambulation test of the MS Functional Composite (MSFC), reflects only the speed component of walking. The lack of sensitivity to other components of gait adds to the floor effect.
Methods and patients: In the SSST, the patient is instructed to walk as quickly as possible from one end to the other of a rectangular field measuring 1 x 5 m, while kicking five cylinder blocks out of five circles marked on the floor. Some 151 MS patients with the Expanded Disability Status Scale (EDSS) score 0-6.5 and 64 normal controls performed the SSST and the T25FW. In addition, 41 patients performed the tests twice.
Results: The range of the SSST (4.7-35.1 seconds) was wider than that of the T25FW (3.5-22.6 seconds). Using control mean + 2 SD as cut off, 107 patients had abnormal SSST, while 100 patients had abnormal T25FW. The T25FW (mean) increased 2.1 seconds over the EDSS range of 0-4.0, while the SSST increased 4.9 seconds. The intra-class correlation between repeated tests (r) was 0.95 for the SSST and 0.96 for the T25FW. The correlation between the SSST and the T25FW was high (r=0.92).
Conclusion: The SSST seems to be superior to the T25FW in terms of dynamic range, floor effect and discriminatory power. The SSST is a relevant alternative for the T25FW as the ambulation component of the MSFC.