engleski

Contralateral and ipsilateral corticobulbar pathway projections for laryngeal muscles in healthy subjects and patients

Introduction: Here we present assessment of excitability of contralateral and ipsilateral corticobulbar pathways, using the methodologies of navigated transcranial magnetic stimulation (nTMS) and transcranial electrical stimulation (TES). Methods: In the present study we applied event- related nTMS generating modified patterned nTMS protocol to the primary motor cortex for laryngeal muscle representation of the left and right hemisphere, respectively, and recorded contralateral (left hemisphere stimulation) and ipsilateral (right hemisphere stimulation) corticobulbar motor evoked potentials (CoMEPs) from the right cricothyroid muscle in the group of 11 healthy subjects. In the group of 15 patients under undergoing craniotomy, CoMEPs were recorded from bilateral cricothyroid muscles by applying TES over C3/Cz and C4/Cz. Results: In 5 out of 11 healthy subjects both contralateral and ipsilateral CoMEPs were recorded from right cricothyroid muscle. In 8 out of 15 patients contralateral and ipsilateral CoMEPs were elicited with TES over C3/Cz, while in 5 out of 15 patients contralateral and ipsilateral CoMEPs were elicited with TES over C4/Cz. Contralateral CoMEP amplitude responses were significantly larger compared to ipsilateral CoMEP amplitudes in both groups. Discussions: We obtained significantly larger amplitude responses of contralateral CoMEPs from laryngeal muscles compared to ipsilateral CoMEPs amplitude using nTMS in healthy subjects and TES in patients. This confirms bilateral nature of corticobulbar pathways projections for laryngeal muscles, with contralateral domination. These findings will influence preoperative and intraoperative CoMEPs monitoring and mapping of primary motor cortex for laryngeal muscles, and facilitate neurophysiologic research of motor speech disorders

corticobulbar pathway; laryngeal muscles; cortical excitabilty

nije evidentirano