The ability of the instrumented tandem walking tests to discriminate fully ambulatory people with MS from healthy adults.

BACKGROUND: People with multiple sclerosis (PwMS) experience walking and balance deficits at the initial phases of the disease, even when classified as only minimally disabled. Complex balance tasks, such as tandem walking, are probably more sensitive in detecting mild balance difficulties compared to the standard traditional tests in this population. RESEARCH QUESTION: The aim was to investigate different types of 3-meter tandem walking tests in fully ambulatory PwMS. METHODS: This observational case-control study included 50 participants; 25 PwMS, 17 women and 8 men, aged 35.2 (S.D = 8.6) and 25 healthy subjects, 18 women and 7 men, aged 34.3 (S.D = 6.1). The 3-meter tandem walk tests were performed during a single session. Each subject completed a sequence of 3 consecutive tests under 3 different task conditions: normal tandem walking, backward tandem walking and cognitive tandem walking. Tandem walking tests were evaluated via three small, lightweight axial wearable accelerometers (APDM, Oregon, USA). RESULTS: The mean EDSS for the MS group was 1.6 (S.D = 0.6) indicating minimal disability. PwMS walked slower and at a slower pace, with a prolonged double support and decreased swing phase compared to healthy subjects in normal and backward conditions. In contrast, during the cognitive task, non-significant differences were found in gait measures between the PwMS and the healthy controls. Significant differences were found between task conditions for all participants. All reduced their walking speed and walked at a slower pace in both the cognitive and backward conditions compared to the normal tandem walk condition. However, non-significant scores were found for the condition X group factor. SIGNIFICANCE: The study provides new insights into the 3-meter tandem walk test. Findings should improve evaluation and training of dynamic balance in fully ambulatory PwMS.

The contribution of the instrumented Timed-Up-and-Go test to detect falls and fear of falling in people with multiple sclerosis.

Fear of falling (FoF) and actual falling typifies two common complaints in people with MS (PwMS). The objective of our study was to examine the Instrumented Timed-Up-and-Go test (ITUG) in relation to falls and FoF in PwMS. This case-control study comprised 75 participants; 50 PwMS (33 women), aged 44.2 (S.D = 7.2) and 25 healthy subjects (18 women) aged 44.4 (S.D = 8.6). The ITUG test was evaluated by the APDM Mobility lab (Portland, OR, USA) and was completed under two task conditions, normal and while performing a cognitive test (ITUG-cog). FoF was evaluated by the FES-I questionnaire. PwMS were divided into subgroups of fallers and non-fallers based on their fall history. Total duration to complete the ITUG and ITUG-cog was higher in the PwMS group compared to the healthy controls. Total duration to complete the ITUG-cog was higher compared to the normal ITUG in both groups. However, non-significant differences were found for the condition x group factor. The total duration to complete the ITUG was increased in the MS fallers compared to the non-fallers. No other differences in ITUG measures were found between MS subgroups. According to the regression analysis, the sit-to-stand phase explained 22.7% of the variance relating to FoF in PwMS (R2 = 0.227). The study provides new insights into the TUG test in PwMS. The sit-to-stand transition appears to be a major component associated with FoF. Furthermore, the cognitive-motor interference in conjunction with the ITUG is probably not unique in PwMS.

Cognitive-motor interference in multiple sclerosis: What happens when the gait speed is fixed?

During the last decade, numerous studies have confirmed a coupling between walking performance and cognition in people with multiple sclerosis (PwMS). Our aim was to provide new insights into a walking-cognitive dual-task (DT) in PwMS. We tested the DT phenomenon by controlling the walking speed using an instrumented treadmill. Thirty PwMS (20 women) with a mean age 40.1 (SD=12.0) participated in the study. Twenty-one healthy subjects served as controls. Each subject completed a sequence of tests: a) Normal walking (ST) - the participant walked on the instrumented treadmill at a comfortable walking speed for 1min; b) Cognitive evaluation (ST) - subjects performed two cognitive tests while seated; c) DT cognitive tests performed while walking on the treadmill at the identical speed performed during normal walking. Outcome measures were spatio-temporal parameters of gait (mean and variability), the Word List Generation Test (WLG) and the Serial-3 Subtraction Test. MS participants significantly decreased their cadence while increasing their stride length during the DT condition compared to the ST condition. Non-significant differences were observed for the WLG and Serial-3 Subtraction Cognitive Tests between the ST condition and the DT condition in both the MS and healthy groups. In terms of gait variability parameters, MS subjects demonstrated a 2 to 3-fold greater gait variability compared to the healthy controls. Non-significant differences in gait variability parameters were observed between the ST and DT conditions in both the MS and control groups. This study provides new insights into the DT phenomenon in the MS population.