Towards assessing cortico-spinal excitability bilaterally: validation of a double-coil TMS method

Transcranial magnetic stimulation (TMS) has been used to monitor corticospinal excitability (CSE) changes in various contexts. Habitually, single- coil TMS is applied over one primary motor cortex (M1) eliciting motor-evoked potentials (MEPs) in the contralateral hand. However, in many situations, it would be useful to obtain MEPs in both hands at once, to track CSE bilaterally. Such an approach requires stimulating both M1 concurrently while avoiding interference between the two stimuli. Objective: We examined MEPs obtained using a double-coil approach where the two M1 are stimulated with a 1ms inter-pulse interval (double-coil1ms). Methods: MEPs were acquired at five different intensities using single- (MEPsingle) or double-coil1ms TMS (MEPdouble) at rest (n=32). Given the 1ms interval, MEPs either resulted from a 1st (MEPdouble-1) or 2nd (MEPdouble-2) pulse (all conditions counterbalanced). Results: MEPsingle, MEPdouble-1 and MEPdouble-2 were all comparable, whatever the intensity of stimulation. Conclusion: Double-coil1ms TMS seems appropriate to assess CSE bilaterally.Master [60] en kinésithérapie et réadaptation, Université catholique de Louvain, 201