Article

Two simultaneously performed tasks may compete for common brain
network resources in patients with multiple sclerosis (MS), suggesting the
occurrence of a cognitive-motor interference. While this phenomenon has been well
described for walking and gait, data on static balance are scarce. METHODS: In
this cross-sectional study, 92 patients and 46 sex/age-matched healthy controls
(HCs) were tested by means of static posturography under eyes opened (single-task
condition) and while performing the Stroop word-colour task (dual-task
condition), to estimate the dual-task cost (DTC) of standing balance. The patient
group also underwent the Expanded Disability Status Scale, 25-foot walking test,
12-item MS walking scale, Modified Fatigue Impact Scale, and Symbol Digit
Modalities Test. RESULTS: Patients had larger postural sway under both
single-task and dual-task conditions (p<0.001), as well as greater DTC of
standing balance (p=0.021) than HCs. Although secondary progressive (SP) patients
had larger sway in both conditions than relapsing-remitting (RR) patients
(p<0.05), these latter ones exhibited a greater DTC of postural balance
(p=0.045). Deficits in sustained attention and information processing speed, as
assessed by the SDMT, were also independently associated with the magnitude of
DTC of standing balance (p=0.005). CONCLUSIONS: The phenomenon of cognitive-motor
interference might be unmasked by a dual-task posturography and was associated
with impaired sustained attention and information processing speed, especially in
RR patients. The smaller DTC of standing balance observed in SP patients may be
due to the ceiling effect of postural sway, or alternatively to the lack of
postural reserve which constrained the more disabled patients to prioritize the
balance over the cognitive task.
CI - Copyright (c) 2015 Elsevier B.V. All rights reserved.

Langue : ANGLAIS