Effect of monaural and binaural altered auditory feedback on stuttering frequency.

The effect of monaural and binaural alterations in auditory feedback on stuttering frequency was investigated. Eleven participants who stutter read aloud under nonaltered auditory feedback (NAF) and monaural and binaural conditions of frequency altered feedback [(FAF), on-quarter octave shift upward] and delayed auditory feedback [(DAF), 50-ms delay] at a normal speech rate. Relative to the NAF condition, reductions in stuttering frequency of approximately 60%-75% were found with the altered auditory feedback conditions. Post hoc single-df comparisons revealed a reduction in stuttering frequency with altered auditory feedback versus NAF (p < 0.0001), a greater reduction in stuttering frequency for binaural compared to monaural altered auditory feedback (p = 0.028), and nonsignificant differences in stuttering frequencies for right versus left monaural conditions (p = 0.54) and DAF versus FAF (p = 0.70).