Table 1.
Baseline characteristics of people with MS and healthy control volunteers.
Figure 1.
Mean walking speed (MWS) in healthy volunteers and in different subgroups of the pMS population.
The same general pattern of MWS differences across the different walking paradigms is observed in every group (T25FW+>T100MW>T25FW>T500MW). In the 4 walking tests, the MWS was significantly slower for each subset of the pMS population compared to healthy volunteers (all p<0,0001), including pMS with a low level of disability according to their EDSS status (EDSS≤2.0, A) or an apparently unlimited MrWD (MrWD≥4000 m, B).
Table 2.
Timed performances1 of respective populations in the different walking tests.
Figure 2.
MWS over five successive 100 m interval laps along the T500MW.
Subgroup analysis are presented in healthy volunteers and in different subgroups of the pMS population, stratified according to their EDSS (A), their maximum reported walking distance (MrWD) (B), and their pyramidal (C), cerebellar (D) and sensitive (E) functional scores (FS). The dashed lines represent the comparison between the “baseline” MWS of the first 100 m (T0–100MW) and the “final” MWS of the last 100 m (T400–500MW) for all subgroups. t-test values were *p<0.05, **p<0.01, ***p<0.0001.
Figure 3.
Quantification of ambulation fatigability through the Deceleration Index (DI).
Ambulation fatigability was evaluated through the integration of the fastest (T25FW+) and the lowest (T400–500MW) measurable WS, which were obviously highly statistically different in all pMS subgroups and healthy volunteers (A, all p<0,0001). Absolute WS differences were however very similar between all groups (ranging from 0.22 m/s for FS S = 3 to 0.31 m/s for EDSS 2.5–3.5 and Controls). This is why further comparisons between groups were focused on relative WS changes. No significant correlation could be found between the individual values of relative deceleration evaluated by the difference of MWS on the T25FW+ and on the T400–500MW (expressed as percentage of the T25FW+ MWS) and the level of walking impairment according to the T25FW (B) or the EDSS status (C). Deceleration Index (DI) calculated as the ratio between MWS of the T400–500MW divided by MWS of the T25FW+ (D) in healthy volunteers and in different subgroups of the MS population.