Persons with Multiple Sclerosis Exhibit Strength Asymmetries in both Upper and Lower Extremities

To characterize strength asymmetries in the upper and lower extremities in persons with multiple sclerosis (PwMS) with severe disability, and examine associations between asymmetries and functional, symptomatic, and participatory outcomes.

Cross-sectional.

University research laboratory.

25 PwMS with Expanded Disability Status Scale scores between 6.0-8.0.

Bilateral strength and asymmetry scores for muscle groups at the ankle, knee, and shoulder joints in addition to grip strength.

Significant differences were observed between all contralateral strength measures, with asymmetry scores ranging between 20-32%. A high prevalence of asymmetry (i.e., score>10%) was observed for all strength measures, with 92% of participants having four or more affected measures. Significant associations were observed between dorsiflexion asymmetry and physical health-related quality of life (ρ= -0.69; p<0.001), and between shoulder flexion asymmetry and lower extremity function (ρ= -0.62; p=0.001). Plantarflexion (ρ= 0.61; p=0.003) and knee flexion (ρ= 0.63; p=0.002) asymmetry were significantly associated with lower extremity functional asymmetry.

A high prevalence of asymmetry in the upper and lower extremities was observed, with asymmetry scores exceeding those previously reported in PwMS with mild-to-moderate disability. Rehabilitation strategies should consider a full body approach to address strength asymmetries.