Exploring factors contributing to fatigability in people with multiple sclerosis: A moderation model analysis

Fatigability in people with multiple sclerosis (PwMS) arises from increased perceived and performance fatigability, contributing to functional decline.

To explore factors influencing fatigability and the moderating role of fear of falling on balance confidence.

In total, 66 PwMS participated in this study. Perceived fatigability was assessed after a 10-minute walk test by dividing the tiredness rating by the distance walked. Performance fatigability was calculated as the change in walking speed (at 2.5 and 10 min) divided by the distance walked. Participants completed the International Physical Activity Questionnaire (IPAQ), Modified Falls Efficacy Scale (MFES), Fatigue Severity Scale (FSS), and Activities-specific Balance Confidence (ABC) Scale. Statistical analyses comprised correlation, linear regression, and moderation analyses.

Perceived and performance fatigability were positively correlated with the number of falls and FSS score and negatively correlated with IPAQ, MFES, and ABC scores. Regression analysis revealed that the ABC score [β = -0.41; 95 % confidence interval (CI): -0.25 to -0.02; p < 0.02] and number of falls (β = 0.37; 95 % CI: 1.76-4.67; p < 0.000) were key predictors of perceived fatigability. The MFES score (β = -0.40; 95 % CI: -0.33 to 0.00; p < 0.05) and number of falls (β = 0.29; 95 % CI: 0.09-0.50; p < 0.005) predicted performance fatigability. Fear of falling moderated the relationship between balance confidence and perceived fatigability (β = 0.040; 95 % CI: 0.008-0.072; p = 0.014).

These findings highlight the need to address fear of falling and confidence. Fall education strategies may improve fatigability and functional mobility.