Preibisch Christine, Neumann Katrin, Raab Peter, Euler Harald A, von Gudenberg Alexander W, Lanfermann Heinrich, Giraud Anne-Lise
Department of Neuroradiology, University of Frankfurt, Frankfurt, Germany.
Neuroimage. 2003 Oct;20(2):1356-64. doi: 10.1016/S1053-8119(03)00376-8.
There is recent evidence of focal alteration in fibre tracts underlying the left sensorimotor cortex in persistent developmental stuttering (PDS) [Lancet 360 (2002) 380]. If, as proposed, this anatomical abnormality is the cause of PDS, then overactivation in the right hemisphere seen with functional neuroimaging in stutterers may reflect a compensatory mechanism. To investigate this hypothesis, we performed two functional magnetic resonance imaging (fMRI) experiments. The first showed systematic activation of a single focus in the right frontal operculum (RFO) in PDS subjects during reading, which was not observed in controls. Responses in this region were negatively correlated with the severity of stuttering, suggesting compensation rather than primary dysfunction. Negative correlation was also observed during the baseline task that consisted in passive viewing of meaningless signs, indicating that RFO compensation acts independently of specific demands on motor speech output. The second experiment, that involved a covert semantic decision task, confirmed that RFO activation does not require overt utterances or motor output. In combination these findings suggest that the RFO serves a nonspecific compensatory role rather than one restricted to the final stages of speech production.
近期有证据表明，持续性发育性口吃（PDS）患者左感觉运动皮层下的纤维束存在局灶性改变[《柳叶刀》360卷（2002年）第380页]。如果如所提出的那样，这种解剖学异常是PDS的病因，那么口吃者功能性神经成像显示的右半球过度激活可能反映了一种代偿机制。为了研究这一假设，我们进行了两项功能磁共振成像（fMRI）实验。第一项实验显示，PDS受试者在阅读过程中，右侧额盖（RFO）的单个焦点有系统性激活，而在对照组中未观察到这种情况。该区域的反应与口吃严重程度呈负相关，表明是代偿而非原发性功能障碍。在由被动观看无意义符号组成的基线任务期间也观察到了负相关，这表明RFO代偿的作用独立于对言语运动输出的特定要求。第二项实验涉及一项隐蔽的语义决策任务，证实RFO激活不需要明显的发声或运动输出。综合这些发现表明，RFO发挥的是一种非特异性代偿作用，而不是仅限于言语产生的最后阶段的作用。
