Laryngeal behavior during stuttering: a further study.

The purpose of this study was to provide detailed, objective descriptions of stutterers' laryngeal behavior during instances of stuttering within conversational speech. Subjects were 11 adult stutterers who produced stutterings (sound prolongations and sound/syllable repetitions) while their laryngeal behaviors were observed by means of a flexible fiber-optic nasolaryngoscope (fiberscope). Laryngeal behaviors during 86 of the 11 stutterers' stutterings were categorized as adducted, intermediate, or abducted. Results indicate that during sound prolongations the vocal folds were more likely to be adducted and less variable in their movement than during sound/syllable repetitions. Results further indicated that the voicing characteristics of the stuttered sound (voiceless vs. voiced) and the type of stuttering (sound prolongation vs. sound/syllable repetition) interactively influenced laryngeal behavior. It is hypothesized that a complex interaction among the laryngeal, articulatory, and respiratory systems contribute to the occurrence of the inappropriate abductory and/or adductory laryngeal behavior which characterizes prolonged or repeated (stuttered) speech segments.