Cut-points of the 6-min walk test, the six spot step test, and the timed-25-foot walk test discriminating impaired from non-impaired walking capacity in persons with Multiple sclerosis.

Background: Assessing and interpreting walking capacity in persons with Multiple sclerosis (PwMS) is essential in clinical practice and research - and thus for PwMS themselves - yet research evaluating cut-points is limited. The present study aims to establish cut-points for 6-min walk test (6MWT), six spot step test (SSST), and timed 25-foot walk test (T25FWT) in PwMS.

Methods: Classification of PwMS having walking impairments and PwMS having limited or no walking impairments was based on distinct benchmarks for each walking test, as derived from the 12-item Multiple Sclerosis Walking Scale (MSWS-12) on a 5-point Likert scale. Cut-points, area under the curve (AUC), sensitivity (Se), and specificity (Sp) were established using receiver operating characteristic curve analyses.

Results: A total of n = 211 ambulatory PwMS were enrolled (68% females, 54 ± 11 years, patient-determined disease step 2.9 ± 1.9 [range; 0-7], 65.1% relapse-remitting Multiple sclerosis). The following cut-points between the two groups were established: 6MWT (446 m; AUC = 0.82, Se = 0.87, Sp = 0.78), SSST (0.121 rounds/s (corresponding to 8.3 s); AUC = 0.80, Se = 0.84, Sp = 0.75), and T25FWT (1.39 m/s (corresponding to 5.5 s); AUC = 0.79, Se = 0.89, Sp = 0.69).

Conclusion: Cut-points discriminating PwMS having walking impairments vs. PwMS having limited or no walking impairments were identified for 6MWT (446 m), SSST (8.3 s), and T25FWT (5.5 s).