Forster D C, Webster W G
Department of Psychology, Carleton University.
Dev Neuropsychol. 2001;19(2):125-45. doi: 10.1207/S15326942DN1902_1.
The neurological basis of stuttering is associated with anomalies of interhemispheric relations and of the neural mechanisms of speech-motor control, specifically those involving the supplementary motor area (SMA). Stuttering typically develops through childhood and adolescence but many children will recover without formal treatment or intervention. The hypothesis that such spontaneous recovery is related to a maturation of the SMA is explored. Four experimental tasks were performed by adults whose stuttering has persisted, adults who reported having stuttered as children, and a control group of adults who reported never having stuttered. A Sequence Reproduction Finger Tapping task (Webster, 1986) and a Bimanual Crank Turning task (Preilowski, 1972) examined the functioning of the SMA, and 2 Divided Visual Field tasks examined asymmetries of hemispheric activation. The overall pattern of results for persistent stutterers compared to nonstutterers was consistent with motor-perceptual anomalies previously reported in the literature. The Bimanual Crank Turning task revealed additionally that the bimanual coordination deficits reported in adults who stutter are kinesthetically based and mediated through anterior callosal systems, including the SMA. Ex-stutterers were similar to nonstutterers in their performance of the motor control tasks, but similar to persistent stutterers in perceptual asymmetries associated with Divided Visual Field tasks. Taken together, the results from the four experimental tasks support the general hypothesis that an anomaly in interhemispheric relations and a deficit in the mechanisms of speech-motor control are each a necessary but not sufficient condition for stuttering and that recovery from childhood stuttering reflects a maturation of the mechanisms of speech-motor control.
口吃的神经学基础与半球间关系异常以及言语运动控制的神经机制异常有关，特别是那些涉及辅助运动区（SMA）的机制。口吃通常在儿童期和青少年期出现，但许多儿童无需正规治疗或干预就能康复。本文探讨了这种自发康复与辅助运动区成熟有关的假说。让成年口吃者、曾在儿童期口吃的成年人以及从未口吃的成年对照组完成四项实验任务。一项序列再现手指敲击任务（Webster，1986）和一项双手曲柄转动任务（Preilowski，1972）用于检测辅助运动区的功能，两项视野分割任务用于检测半球激活的不对称性。与非口吃者相比，持续性口吃者的总体结果模式与文献中先前报道的运动感知异常一致。双手曲柄转动任务还显示，口吃成年人中报告的双手协调缺陷是基于动觉的，并通过包括辅助运动区在内的胼胝体前系统介导。曾经口吃者在运动控制任务的表现上与非口吃者相似，但在与视野分割任务相关的感知不对称方面与持续性口吃者相似。综合来看，四项实验任务的结果支持了这一总体假说，即半球间关系异常和言语运动控制机制缺陷各自都是口吃的必要但非充分条件，并且儿童口吃的康复反映了言语运动控制机制的成熟。
