4-meter walk test in patients with Parkinson's disease: A reliability and validity study.

Objective: The purpose of the study was to examine the test-retest reliability of the 4-Meter Walk Test (4-MWT), the minimum detectable change (MDC) in the 4-MWT, and the concurrent and known-group validity of the 4-MWT in patients with Parkinson Disease (PwPD).

Design: A total of 42 PwPD and 33 healthy people participated in this study. Reliability was quantified using intraclass correlation coefficients (ICC) and the MDC. The 4-MWT was administered with a fast walking protocol. Validity was assessed by correlating the 4-MWT times with the scores of the 10-Meter Walk Test (10-MWT), the Dynamic Gait Index (DGI), the Timed Up and Go (TUG) Test, the Freezing of Gait Questionnaire (FOG-Q), the Hoehn and Yahr (H&Y) Scale, and the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). The 4-MWT times were also compared between fallers and non-fallers among PwPD.

Results: The 4-MWT demonstrated excellent test-retest reliability (ICC= 0.957). The MDC was determined as 0.14 m/s. The 4-MWT had fair to excellent correlations with the other outcome measures (correlation coefficients ranged from -0.428-0.937; p < 0.05 for all). Significant differences in the 4-MWT were found between fallers and non-fallers with PwPD (p < 0.05).

Conclusion: The 4-MWT has excellent test-retest reliability, concurrent and known-group validity for PwPD. 4-MWT may be a useful test method for assessing forward walking in the absence of adequate space and equipment in order to monitor the progression of the disease and the effectiveness of the treatments applied.