An investigation of the effects of a speech-restructuring treatment for stuttering on the distribution of intervals of phonation.

Purpose: The purpose of this study was to investigate whether stuttering reductions following the instatement phase of a speech-restructuring treatment for adults were accompanied by reductions in the frequency of short intervals of phonation (PIs). The study was prompted by the possibility that reductions in the frequency of short PIs is the mechanism underlying such reductions in stuttering.

Method: The distribution of PIs was determined for seven adults who stutter, before and immediately after the intensive phase of a speech-restructuring treatment program. Audiovisual recordings of conversational speech were made on both assessment occasions, with PIs recorded with an accelerometer.

Results: All seven participants had much lower levels of stuttering after treatment but these were associated with reductions in the frequency of short PIs for only four of them. For the other three participants, two showed no change in frequency of short PIs, while for the other participant the frequency of short PIs actually increased.

Conclusions: Stuttering reduction with speech-restructuring treatment can co-occur with reduction in the frequency of short PIs. However, the latter does not appear necessary for this reduction in stuttering to occur. Thus, speech-restructuring treatment must have other, or additional, treatment agents for stuttering to reduce.