Research Center for Advanced Technologies, Tokyo Denki University, Inzai, Chiba, Japan.
Neuroimage. 2011 Aug 15;57(4):1507-16. doi: 10.1016/j.neuroimage.2011.05.039. Epub 2011 May 23.
External auditory pacing, such as metronome sound and speaking in unison with others, has a fluency-enhancing effect in stuttering speakers. The present study investigated the neural mechanism of the fluency-enhancing effect by using functional magnetic resonance imaging (fMRI). 12 stuttering speakers and 12 nonstuttering controls were scanned while performing metronome-timed speech, choral speech, and normal speech. Compared to nonstuttering controls, stuttering speakers showed a significantly greater increase in activation in the superior temporal gyrus under both metronome-timed and choral speech conditions relative to a normal speech condition. The caudate, globus pallidus, and putamen of the basal ganglia showed clearly different patterns of signal change from rest among the different conditions and between stuttering and nonstuttering speakers. The signal change of stuttering speakers was significantly lower than that of nonstuttering controls under the normal speech condition but was raised to the level of the controls, with no intergroup difference, in metronome-timed speech. In contrast, under the chorus condition the signal change of stuttering speakers remained lower than that of the controls. Correlation analysis further showed that the signal change of the basal ganglia and motor areas was negatively correlated with stuttering severity, but it was not significantly correlated with the stuttering rate during MRI scanning. These findings shed light on the specific neural processing of stuttering speakers when they time their speech to auditory stimuli, and provide additional evidence of the efficacy of external auditory pacing.
外部听觉起搏，如节拍器声音和与他人齐声说话，对口吃者有流畅性增强的效果。本研究通过功能磁共振成像 (fMRI) 研究了这种流畅性增强效果的神经机制。12 名口吃者和 12 名非口吃者在进行节拍器定时说话、合唱说话和正常说话时进行了扫描。与非口吃者对照组相比，口吃者在节拍器定时和合唱说话条件下，与正常说话条件相比，上颞叶的激活明显增加。基底神经节的尾状核、苍白球和壳核在不同条件下和口吃者与非口吃者之间表现出明显不同的信号变化模式。与非口吃者对照组相比，口吃者在正常说话条件下的信号变化明显较低，但在节拍器定时说话条件下，信号变化升高到与对照组相同的水平，且无组间差异。相比之下，在合唱条件下，口吃者的信号变化仍然低于对照组。相关分析进一步表明，基底神经节和运动区的信号变化与口吃严重程度呈负相关，但与 MRI 扫描期间的口吃率无显著相关性。这些发现揭示了口吃者在受到听觉刺激时对言语进行定时的特定神经处理，并为外部听觉起搏的疗效提供了额外的证据。
