Visual Feedback and Postural Control in Multiple Sclerosis

Abstract: As people with multiple sclerosis (pwMS) manifest heterogeneous demyelinating lesions
that could affect somatosensory or vestibular ways, visual stimulus as feedback could be especially
relevant to achieve postural control. This has clinical importance for the development of preventive
measures and rehabilitation therapies in order to avoid falls and accidents in this group. In our study,
we objectively evaluated the influence of visual feedback on the stabilization of balance in pwMS
versus healthy controls (HC) and its potential utility in clinical evaluation. Static posturography tests
were performed in 99 pwMS and 30 HC. Subjects stood on a force platform with open and closed
eyes. During this procedure, three balance parameters were obtained for both vision conditions:
average sway, average speed, and average speed of sway. Neurostatus-Expanded Disease Disability
Score (EDSS) and Multiple Sclerosis Functional Composite (MSFC) were performed in parallel as
well. A two-way mixed repeated measures ANCOVA, controlling for sex and age, was performed
to evaluate the effect of vision, MS diagnosis, and the interaction of both in static posturography
parameters. The difference between both closed and open eyes conditions was calculated for each
parameter and further analyzed according to MS-relevant clinical variables. The magnitude of the
vision effect differed between pwMS and HC as a significant interaction between the vision and the
MS diagnosis in the delineated area (p < 0.001) and average speed of sway (p = 0.001) was seen.
These parameters had a greater increase in pwMS than in HC after closing eyes. For the average
sway, a significant main effect of vision was present (p = 0.047). Additionally, the differences obtained
between open and closed eyes conditions assessed with the delineated area and average speed of sway
were moderately correlated to the assessed clinical tests EDSS (r = 0.405 and r = 0.329, respectively)
and the MSFC (r = −0.385 and r = −0.259, respectively). In our study, pwMS were more dependent
of visual feedback than HC to maintain postural control. This easy and short evaluation by static
posturography could support the development of targeted preventive measures and interventions
in pwMS