Pyramidal function and disability in patients with multiple sclerosis

Abstract

Introduction: Multiple sclerosis (MS) is an immune-mediated inflammatory disease that attacks myelinated axons in CNS and causes physical disability. Transcranial magnetical stimulation (TMS) gives us a possibility to activate cortical motor cortex and detect pathological changes in pyramidal tract even in subclinical presentations. Methods: TMS of motor cortex was performed on 30 healthy controls and 20 patients with relapsing-remitting multiple sclerosis. Central motor conduction time (CMCT) and amplitude ratio were investigated. Motor functional score (mFS) and the expanded disability status scale (EDSS) score were determined for each patient. Results: CMCT of all limbs was prolonged in patients with relapsing-remitting multiple sclerosis (p<0.001). Whereas the amplitude ratio of all limbs was reduced in patients with MS (p<0.05). All interside asymmetries for CMCT and amplitude ratio were prolonged in patients comparing to healthy controls (p<0.05). The number of pathological parameters moderately correlated with mFS score (r=0.69, p=0.002) as well as with the EDSS score (r=0.52, p=0.034). Conclusions: All neurophysiological parameters were significantly pathological in patients comparing to healthy controls. The number of pathological parameters correlated with mFS and EDSS score. Motor functional score correlated with the level of demyelination of central motor neuron.