Physiological factors related to delayed auditory feedback and stuttering: a review.

Delayed auditory feedback (DAF) generally produces speech disturbances in normal speakers and improved fluency in stutterers. Several theorists have proposed that the speech disruptions of normal persons under such delayed feedback are an analog of stuttering. Related research has linked delayed auditory feedback and stuttering to several physiological factors. A review of familial relationship, age, sex, stress, speech characteristics, and sound conduction is presented. A brief integration of the factors and directions for research is presented.