IRCCS Ospedale San Camillo, via Alberoni 70, 30126 Venice, Italy.
Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy.
Brain Lang. 2020 Jun;205:104774. doi: 10.1016/j.bandl.2020.104774. Epub 2020 Mar 2.
Previous studies regarding developmental stuttering (DS) suggest that motor neural networks are strongly affected. Transcranial magnetic stimulation (TMS) was used to investigate neural activation of the primary motor cortex in DS during movement execution, and the influence of muscle representations involved in movements on "surrounding" ones. TMS was applied over the contralateral abductor digiti minimi (ADM) motor representation, at rest and during the movement of homologue first dorsal interosseous muscles (tonic contraction, phasic movements cued by acoustic signalling, and "self-paced" movements). Results highlighted a lower cortico-spinal excitability of ADM in the left hemisphere of stutterers, and an enhanced intracortical inhibition in their right motor cortex (in comparison to fluent speakers). Abnormal intracortical functioning was especially evident during phasic contractions cued by "external" acoustic signals. An exaggerated inhibition of muscles not directly involved in intended movements, in stuttering, may be useful to obtain more efficient motor control. This was stronger during contractions cued by "external" signals, highlighting mechanisms likely used by stutterers during fluency-evoking conditions.
先前关于发展性口吃（DS）的研究表明，运动神经网络受到强烈影响。经颅磁刺激（TMS）用于研究 DS 患者在执行运动时初级运动皮层的神经激活，以及参与运动的肌肉表象对“周围”肌肉表象的影响。TMS 应用于对侧小指展肌（ADM）运动表象，在休息时和同源第一背侧骨间肌（紧张收缩、声信号提示的相位运动和“自我调节”运动）运动时。结果表明，口吃者左半球 ADM 的皮质脊髓兴奋性较低，其右侧运动皮层的皮质内抑制增强（与流利说话者相比）。在“外部”声信号提示的相位收缩过程中，皮质内功能异常尤为明显。口吃者在不直接参与意向运动的肌肉中存在过度抑制，这可能有助于获得更有效的运动控制。在“外部”信号提示的收缩过程中，这种抑制作用更强，突出了口吃者在引发流畅性条件下可能使用的机制。
