Further construct validity of the Timed Up-and-Go Test as a measure of ambulation in multiple sclerosis patients

BACKGROUND: The importance of mobility impairments in people with multiple sclerosis (PwMS) denotes a need for valid, reliable, sensitive and feasible clinical measuring tools. The Timed Up-and-Go (TUG) test is a unique mobility measure as it captures other functions apart from walking, i.e., rising out of a chair or turning around an object. AIM: To expand the construct validity of the TUG test in PwMS and determine the ability of the TUG score to discriminate between four levels of disability between fallers, recurrent fallers and non-fallers. DESIGN: Cross-sectional. SETTING: Multiple SCenter, SCenter, Israel. POPULATIO N: A total of 285 PwMS (176 women) with a mean disease duration of 8.1±8.1 years. METHODS: We retrospectively evaluated and analyzed computerized data of the TUG test, Four Square Step Test (FSST), posturography measures, 2-minute Walk Test (2mWT), Timed 25-foot Walk Test, fall status, Falls Efficacy Scale - International, Modified Fatigue Impact Scale, instrumented cognitive assessment, and the Multiple Sclerosis Walking Scale self-reported questionnaire. RESULTS: The TUG score of the total sample was 9.3±5.1. In terms of the disability subgroups, significant differences were observed between the four groups with the exception of "very mild" to "mild" groups. In terms of fall status, the MS recurrent fallers demonstrated a significantly slower TUG compared to the MS non-fallers. Strong-modest significant correlation scores were found between the TUG and ambulation tests. The strongest scores were found for the FSST and 2MWT; Pearson's r=0.740, -0.731, respectively. CONCLUSIONS: The current study broadens the evidence supporting the usage of the TUG test to assess walking and balance performance in PwMS regardless of the patient's cognitive status. Furthermore, the test can aid in identifying PwMS who are at a high risk of falling. CLINICAL REHABILITATIO N IMPACT : The TUG test is an excellent tool used to assess mobility capabilities in PwMS, monitor disease progression and identify potential MS fallers.