Laryngeal activity accompanying the moment of stuttering: a preliminary report of EMG investigations

Abstract

The existence of a laryngeal component in the stuttering block has long been a subject of speculation. In this investigation, one adult male stutterer and two normally fluent adults served as subjects. Electromyographic recordings were taken from five intrinsic laryngeal muscles and four upper-tract articulators. Comparisons were made of the stuttering subjects' fluent and stuttered utterances of the same words. Similar comparisons were made of the two normal subjects' fluent and “faked” stuttered utterances. Results indicate that fluent utterance is characterized by precise balance and timing of laryngeal abductor and adductor forces. In fluent utterance abductor and adductor forces act reciprocally, whereas, in stuttered utterance, this reciprocity is disrupted. In many stuttered utterances the lateral cricoarytenoid—generally presumed to be an adductor, with the specific function of medial compression—achieved abnormally high levels of activity. Stuttered utterances involving prolongations of vocalic segments were typically characterized by activity of the laryngeal abductor, the posterior cricoarytenoid. These patterns did not occur in normal fluent utterance. [Supported by the National Institute of Dental Research, Grant DE01774.]