Developmental stuttering may be caused by insufficient processing of auditory feedback

Abstract

Developmental stuttering has been scientifically researched for about a hundred years, but the cause is still unknown. Here, a comprehensive causal hypothesis is presented, from the factors contributing to a predisposition for stuttering to the mechanism underlying the core symptoms: A deficit in attention regulation and/or auditory processing abets a misallocation of attention, i.e., of perceptual and processing capacity, during speech; this results in poor processing of the auditory feedback of speech. Insufficiently processed auditory feedback causes error signals in the speech network which, by an error-induced interaction between cerebellum and basal ganglia, interrupts the speech flow against the speaker’s will. The allocation of attention during speech is hypothesized to be a variable state that forms the interface between the physiological pathomechanism of stuttering, on the one hand, and situational, cognitive, and emotional factors influencing stuttering severity, on the other hand; the interaction between both accounts for the situational variability of the disorder. The hypothesis implicates that increased attention to the auditory feedback of speech (listening to one’s voice) reduces stuttering – this opens, both, a way to test the hypothesis and to improve the therapy.