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Human Cortical Motor Representation of the Larynx as Assessed by Transcranial Magnetic Stimulation (TMS)
Author(s) -
Rödel Ralph M.W.,
Olthoff Arno,
Tergau Frithjof,
Simonyan Kristina,
Kraemer Dorit,
Markus Holger,
Kruse Eberhard
Publication year - 2004
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200405000-00026
Subject(s) - transcranial magnetic stimulation , anatomy , larynx , stimulus (psychology) , medicine , stimulation , psychology , psychotherapist
Objectives: To analyze characteristic features and details on motor‐evoked potentials (MEPs) of the cricothyroid and vocalis muscles from single‐pulse cortical transcranial magnetic stimulation (TMS) in normal subjects to characterize cortical motor representation of laryngeal muscles. Study Design: Prospective, experimental investigation on healthy volunteers. Method: MEPs of the cricothyroid and vocalis muscles elicited by cortical TMS with a figure–8‐shaped coil were investigated in two groups of six healthy subjects each, with special regard to MEP amplitude as a function of the coil position on the head surface along the interaural line. Results: Bilateral reproducible responses of the cricothyroid and the vocalis muscles could be observed in all subjects. For the cricothyroid muscle, maximal responses were obtained at mean stimulus positions of 7.5 ± 1.4 cm (contralateral) and of 7.3 ± 1.3 cm (ipsilateral), respectively. For the vocalis muscle, we found maximal responses at mean stimulus positions of 10.3 ± 1.9 cm (contralateral) and of 9.6 ± 1.6 cm (ipsilateral), respectively. Despite a considerable overlap of these coil positions, from which reproducible MEPs could be elicited in both groups of the laryngeal muscles, statistically significant separation of the cricothyroid‐and vocalis‐associated cortical representation areas was possible. Conclusions: Our observations point to two different cortical motor representation areas, with the cricothyroid muscle‐related area being located more medially.