Association Between Motor Pathway Damage and Motor Deficit in Upper and Lower Limb in People With MS

Corticospinal tract damage is common in people with MS, but the degree of clinical symptoms varies. We hypothesize that corticospinal tract lesions are more extensive and severe in people with MS with motor impairments in both upper and lower limbs. We compared three groups of patients: isolated hyperreflexia (A), motor deficits limited to the lower limbs (B), or in both upper and lower limbs (C).

We included 100 people with MS in a prospective cross-sectional study. Corticospinal tract lesions were segmented on 3D FLAIR (brain) and axial T2* and T2-weighted images (cervical and thoracic spinal cord). MP2RAGE quantitative T1 was used to assess microstructural damage severity in the brain and cervical spinal cord corticospinal tract.

Ninety-two people with MS were included in the analysis (A = 38, B = 31, C = 23). Lesion volume was higher in groups B and C than in group A in the brainstem and cervical corticospinal tract (all p < 0.001), and quantitative T1 was higher only in the cervical corticospinal tract (all p < 0.05). In the multivariate analysis, age, disease duration, lesion volume in the brainstem, and quantitative T1 in the cervical spinal cord distinguished group A from groups B and C, but no differentiating factors were identified between groups B and C.

Our study suggests that motor deficit in pwMS was associated with brainstem and cervical spinal cord corticospinal tract damage. Differences between pwMS with lower limb deficits and those with both lower and upper limb deficits could not be established.