A new surface electrode for recording from the posterior cricoarytenoid muscle.

A new pharyngeal surface electrode for recording posterior cricoarytenoid muscle activity through the hypopharyngeal mucosa has been evaluated. The electrode was passed through one nasal passage into the hypopharynx. Correct electrode location was verified by increased activity during inhalation, with decreased activity during phonation. The procedure was evaluated in 45 subjects, 10 normal speakers and 35 patients with dysphonia. Accurate recordings were obtained in 25 subjects (56%). Problems encountered were lack of pharyngeal descent, electrode dysfunction, and signal interference due to phonatory vibration or interarytenoid activity. Signal validity was evaluated in four normal speakers with accurate electrode placement. Significant (p less than or equal to 0.001) increases in PCA activity occurred during tasks requiring vocal fold abduction. The electrode proved to be a useful, noninvasive clinical tool for recording PCA activity in some patients.