Prospective clinical and electrophysiological follow-up on a multiple sclerosis population treated with interferon...

To analyse transcranial magnetic stimulation (TMS) variables in a prospective six-month follow-up pilot study on patients suffering from relapsing-remitting multiple sclerosis (RRMS), satisfying inclusion criteria for interferon (IFN) beta-1a treatment.

So far, no predictive factors are available as to the course of RRMS treated with IFN beta-1 a.

Fifteen RRMS patients were studied before (month 0 (M0)) and after IFN beta-1a onset (M3, M6). The parameters analysed were motor functional score (mFS), Expanded Disability Status Scale (EDSS), and TMS variables - central motor conduction time (CMCT) and amplitude ratio (AR).

Four of the six patients with no motor signs at inclusion, subsequently showed signs of pyramidal dysfunction. All had abnormal M0_TMS variables. The number of M0_TMS abnormalities per patient was greatest in the group that showed mFS worsening, and was significantly correlated with M6_EDSS. The M0_CMCT was significantly correlated with M6_EDSS. During follow-up, the number of patients with abnormal TMS variables decreased from 12/15 to 4/15, and the total number of abnormalities decreased from 33.3 to 16.7%.

TMS variables might be predictive of disease progression. The improvement observed here in the TMS variables may reflect an improvement in MS patients undergoing IFN beta treatment.