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
Camilla Juhl, Kasper Byskov, Lars G. Hvid, Ulrik Dalgas, Uwe M. Pommerich, Anders G. SkjerbækBackground
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).