B D Burke | PubMed Health

PubMed1975

Variables affecting stutterer's initial reactions to delayed auditory feedback.

Twenty male stutterers (7-18 years) described pictures under delayed auditory feedback (DAF). Delay was varied from 0 to 300 msec in 50 msec steps. There was a significant interaction between delay time, age and initial disfluency in terms of disfluent words but not speech rate. Young stutterers (7-12 years) were generally more affected by DAF than older stutterers (13-18 years). Under DAF high disfluent stutterers showed reduced disfluency, whereas low disfluent stutterers either showed little or no change or became more disfluent. Delays of 50-150 msec tended to have an ameliorative effect on stuttering. Conflicting results were obtained when the same subjects repeated short sentences under DAF. The majority of stutterers were fluent when repeating the sentences under no delay, but stuttering increased under DAF. Current explanations of the DAF effect and feedback theories of stuttering do not readily account for these results.

Adolescent↗

PubMed1975

Susceptibility to delayed auditory feedback and dependence on auditory or oral sensory feedback.

Studies of the delayed auditory feedback (DAF) effect have consistently reported marked individual differences in susceptibility to DAF among normal speakers. It has been suggested that speakers showing extreme susceptibility to DAF may be differentially dependent on auditory feedback in regulating their speech production. Assuming this is the case, then a reduction in sensory feedback would also be expected to produce differential effects on these speakers. To test this hypothesis, normative data on the actual range of susceptibility to 180 msec DAF were first obtained from a group of 400 normal male speakers. Subjects from the extremes of this distribution were then tested under conditions that selectively reduces sensory feedback. Auditory masking, whispering and local anaesthesia were used separately and in combination to achieve a reduction in one or more feedback channels (air-conducted, bone-conducted and oral sensory feedback). The results obtained did not support the feedback dependence hypothesis. Measures of reading duration, disfluency and correct syllabel rate revealed similar changes in the speech of high and low susceptible speakers when auditory and/or oral feedback was reduced. Alternative explanations of individual differences in DAF susceptibility are considered.

Adult↗