Interhemispheric disconnection of the motor system in early relapsing remitting multiple sclerosis (RRMS)

Aims: RRMS starts as a focal inflammatory disease but typically progresses to diffuse demyelination and axonal loss. The Corpus Callosum (CC) is often affected in the earliest stages of the disease. Here we employed measures of effective interhemispheric connectivity and microstructural integrity to investigate the role of the motor CC as an early focus of pre-macrostructural disease activity. We then related these measures to the expanded disability status scale (EDSS), disease duration and T2-weighted MRI lesion load. Methods: 33 right-handed early RRMS patients (mean age: 35±8 years; 23 female; median EDSS: 1…