The Two-Minute Walk Test in Persons with Multiple Sclerosis: Correlations of Cadence with Free-Living Walking Do Not Support Ecological Validity

Abstract

The two-minute walk test (2MWT) is a frequently used walking capacity test in persons with multiple sclerosis (pwMS). However, less is known about its relevance with regards to walking capacity during free-living walking performance. Therefore, the ecological validity of the 2MWT was tested by 1. computing free-living minutes with the same intensity (cadence) as during the 2MWT and 2. investigating the relationship between 2MWT cadence and minutes with the same cadence during free-living walking. 20 pwMS aged 44.2 ± 12.2 (Expanded Disability Status Scale (EDSS) score of 3.1 ± 1.4) performed a 2MWT and wore an accelerometer for seven days. The number of pwMS reaching 100%, 90%, 80% or 70% of 2MWT cadence for at least one minute a day and minutes/day with at least 100%, 90%, 80% and 70% of 2MWT cadence during free-living walking was calculated. Six participants reached 100% of the 2MWT cadence for at least one minute/day during free-living walking. A total of 80% 2MWT cadence was the first intensity category that was reached by all participants during free-living walking. No significant correlation was found between cadence in the 2MWT and minutes in which this cadence was reached during free-living walking. Ecological validity with regard to walking intensity could not be confirmed in our study sample.

Open-source dataset reveals relationship between walking bout duration and fall risk classification performance in persons with multiple sclerosis

“…These results are consistent with Storm et al, who found that gait pace significantly increased and variability significantly decreased with increasing bout length [ 24 ]. Karle et al found little correlation between an in-lab 2-minute walk test and free-living walking [ 25 ]. In older adults, Najafi et.…”

“…However, deploying these models remotely comes with additional challenges that may impact model performance. For example, it is well established in PwMS [24][25][26] and other populations [27][28][29] that gait observed in the clinic differs from gait observed remotely (especially for gait speed-dependent variables). Similarly, studies in older adults [30] and PwMS [24] have also discovered that gait parameters change with walking bout duration.…”

Automated Analysis of the Two-Minute Walk Test in Clinical Practice Using Accelerometer Data

“…Walk endurance tests are important to quantify walking parameters accurately [47,48]. Therefore, we applied two novel algorithm-based approaches using accelerator sensors in comparison to the current standard measurement using the odometer in the walking assessment of pwMS.…”

“…For this, the average cadences were processed from the raw acceleration data of an activity monitor. An average cadence between a clinical environment and an outside environment was compared [48]. Unfortunately, both studies did not include a gold standard of measurement to verify the respective measurement system.…”

Pedometers and Accelerometers in Multiple Sclerosis: Current and New Applications

“…For example, researchers and clinicians have typically adopted performance tests to assess physical function and mobility in MS [ 24 ]. However, there is evidence that performance-based tests may not present ecological validity [ 47 ]—these tests and outcomes may not totally reflect free-living performance, which entails unsupervised monitoring in the wild [ 48 ]. Conversely, wearable sensor technology in MS allows for the collection of free-living data that may serve as biomarkers of disease severity and progression.…”