Use of neck strap muscle intermuscular coherence as an indicator of vocal hyperfunction.

Intermuscular coherence in the beta band was explored as a possible indicator of vocal hyperfunction, a common condition associated with many voice disorders. Surface electromyography (sEMG) was measured from two electrodes on the anterior neck surface of 18 individuals with vocal nodules and 18 individuals with healthy normal voice. Coherence was calculated from sEMG activity gathered while participants produced both read and spontaneous speech. There was no significant effect of speech type on average coherence. Individuals with vocal nodules showed significantly lower mean coherence in the beta band (15-35 Hz) when compared to controls. Results suggest that bilateral EMG-EMG beta coherence in neck strap muscle during speech production shows promise as an indicator of vocal hyperfunction.