Role of surface EMG in diagnostics and treatment of muscle tension dysphonia.
In muscle tension dysphonia (MTD) excessive tension of both the internal and external laryngeal muscles is observed. In the present pilot study, 9 pairs of surface electrodes were used to determine the electromyographic (EMG) characteristics of different muscles in the perioral area and anterior neck before and during phonation. Eleven patients with MTD and 5 normal speakers were included within the study. The results show a 6-8-fold increase of EMG activity and/or an alternation of the EMG activity level in the perioral and supralaryngeal muscles before and during phonation in most of the patients with MTD. It is not clear whether these muscles are activated as compensation for excessive tension of internal laryngeal muscles, or whether they are responsible for some of the voice disorders.