EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF FREQUENCY-ALTERED AUDITORY-FEEDBACK ON THE SPEECH OF ADULTS WHO STUTTER

A series of single-subject experiments evaluated the effects of Freque ncy-altered auditory feedback (FAF) on the speech performance of Four adult males who stutter. Using alterations of plus or minus one octave , FAF was compared with normal auditory feedback (NAF) in oral reading and spontaneous speech with measurements made of stuttered intervals, stutter-free speech rate, and speech naturalness. The effects of exte nded FAF conditions on spontaneous speech were also evaluated For two subjects who demonstrated a positive response to FAF. Results showed n o consistencies across subjects in responses to FAF: One subject showe d no response, another produced an initial temporary response, a third showed a deterioration in speech quality with minimal reductions in s tuttering, and a Fourth displayed substantial and sustained improvemen ts in speech performance. Some implications of these findings For curr ent research and theory about the relationship between stuttering and FAF are discussed.