The relationship between prenatal testosterone and developmental stuttering in boys

Abstract

Abstract:Stuttering is a multi-factorial speech disorder characterized by variousdysfluencies in the beginning and/or smooth flow of speech. Its incidenceis about 1% in the general population, with 80% of stuttering cases seen inchildren aged three to eight years. The etiology of developmental stutteringhas not been precisely explained. Several researchers report that neurologicalfactors, especially atypical lateralization of the speech and language processes,play an important role in the etiology of stuttering. Various hypothesessuggest that prenatal testosterone causes atypical hemispheric lateralization.The aim of this study was to investigate the role of prenatal testosterone inthe etiology of developmental stuttering by the use of the ratio of secondand fourth-digit lengths (2D:4D).Totally 133 boys (49 boys who stutter and 84 boys who do not stutter)were included in the study. The age range of children participating in thestudy was determined as 2–12 years. In the comparative evaluation conductedbetween the stuttering group and the control group in terms of their right2D:4D and left 2D:4D ratios, it was found that the left 2D:4D ratio of thepatients was significantly higher than that of the control group.We are of the opinion that prenatal testosterone may play a role in theetiology of developmental stuttering. The present study is the first studyin the literature to reveal a relationship between prenatal testosterone anddevelopmental stuttering.