Assessment of the interest of inhibitory repetitive transcranial magnetic stimulation (rTMS) on unaffected motor cortex in balance disorders in chronic stroke patients

Abstract

To compare the evolution of posturographic and functional balance parameters after Inhibitory rTMS versus Sham stimulation in subjects with chronic stroke. Pilot and feasibility study, randomized, controlled versus Sham (inactive coil), blind (patient, physician applying the stimulation and evaluator), prospective, cross-over, conducted on hemiplegic adults, more than 6 months after stroke documented by imaging, with balance disorders. Subjects received 10 sessions of 1 Hz rTMS and sham stimulation according to randomization, applied on the motor cortex of the unaffected hemisphere. The assessment included posturographic settings (mean centre of pressure trajectory, sway area, centre of pressure velocity) recorded eyes open, eyes closed and in cognitive task conditions, and the balance section of Fugl Meyer score. Of the nine subjects included, we measured a significant improvement in the mean centre of pressure trajectory in medio-lateral axis measured eyes open (10.89 mm ± 10.27 reduction) and eyes closed (8.73 mm ± 10.46 reduction) with a superiority compared to sham stimulation in eyes open condition (7.69 ± 7.20 mm reduction). Other outcome measures were not significantly improved. No adverse effects were reported. This study demonstrated the interest (feasibility and safety) of inhibitory rTMS in chronic hemiparetic subjects with balance disorders and could be a basis for a study on a larger sample with long-term follow-up, completed with electrophysiological assessment and balance functional scales. Such studies are needed to better understand the mechanisms underlying the effects of rTMS in a perspective of application in current practice in the field of neurological rehabilitation.