Transcranial magnetic stimulation (TMS) studies reported consistent and substantial impairments in the central nervous system (CNS) in multiple sclerosis (MS). Studies of peripheral nervous system (PNS) function comprising electromyoneurography (EMNG) reported impairments of the PNS in MS that were less pronounced and inconsistent. Neurophysiological studies are generally small and cross-sectional and with the poor grouping of MS patients according to MS type. The objective of the study is to investigate clinical, neurophysiological, and immunological markers in relapsing-remitting MS patients, and in patients with relapsing-remitting MS treated with immunomodulation. The results of the study may contribute to a better understanding of the pathophysiology of multiple sclerosis and can provide guidance in the diagnosis and treatment of patients with relapsing-remitting MS.