The ability of stutterers and nonstutterers to initiate and terminate phonation during production of an isolated vowel.

This study tested the hypothesis that stutterers have difficulty initiating and terminating phonation independent of the acts of running speech and stuttering. Ten young adult stutterers served as the experimental group. They were matched as a group for age and sex with 10 normal speakers. Subjects from both groups were tested individually. The experimental task required that subjects start and stop phonation as quickly as possible upon hearing each member of a seried of 1000-Hz pure tones appear and then disappear. Subjects' vocalizations were permanently recorded on an optical oscillograph. Results showed that both groups improved (shortened) their voice initiation and termination times from the beginning to the end of the experiment. Typically, however, the stutterers were significantly slower than the control subjects on most of the temporal measures.