Impact of cognitive fatigue on balance in individuals with multiple sclerosis without cognitive impairment

This study aims to examine the impact of cognitive fatigue on balance among individuals with multiple sclerosis (MS) without cognitive impairment.

A total 50 individuals with MS aged 20-50 years, without cognitive impairment and with an Expanded Disability Status Scale (EDSS) score of 0-4, participated in the study. Participants were randomly assigned to either a control group (CG) or a study group (SG). The CG rested for 30 minutes, while the SG engaged in cognitive activities lasting 30-45 minutes to induce cognitive fatigue. Cognitive fatigue was assessed using the Visual Analog Scale (VAS) before and after the tasks. Balance was evaluated using clinical tests: the Functional Reach Test (FRT) and the Single Leg Stance Test (SLST), as well as laboratory assessments including the Modified Clinical Test of Sensory Integration and Balance (mCTSIB) and Limits of Stability (LOS) with static posturography.

Within-group analyses showed a significant increase in cognitive fatigue on the VAS in the SG (p < 0.001). In the mCTSIB, the SG showed significant changes in firm/eyes open, foam/eyes open, and composite scores, while between-group differences were observed only in firm/eyes open and foam/eyes open conditions (p < 0.005). No significant differences were found between groups in LOS, FRT, or SLST outcomes (p > 0.05).

In individuals with MS, the impact observed only in the eyes-open static balance condition suggests that dynamic balance and eyes-closed static balance parameters rely more on automatic mechanisms compared to the eyes-open condition and are not influenced by cognitive fatigue.