Basic and clinical research on speech perception and production

本研究利用正电子发射断层扫描（PET）等脑功能图像，对听力障碍、语言障碍和正常受试者的语言感知和产生的中央处理机制进行了研究。失聪受试者与正常受试者表现出完全相同的听觉关联区激活。但在失聪受试者中，扣带区和辅助运动区被观察到更多的激活。语前失聪受试者的脑成像表现出完全不同的模式。大多数病例通过人工耳蜗听语音时，其听觉关联区几乎没有被激活。另一方面，一些语前失聪的受试者通过唇读激活了听觉关联区。这些结果表明，在语言习得期间，大脑分化应根据语言环境的不同而有所不同。发声方面，布洛卡*区、运动区、辅助运动区、小脑对言语输出有重要作用。然而，在发声过程中，听觉关联区没有被激活，这表明听觉反馈系统不需要进行日常对话发声。相反，当一个语音被扭曲时，听觉关联区域开始被激活，这意味着反馈系统在修复发声。这种情况与语言习得时期的情况类似。综上所述，我们可以根据语言环境的不同观察到不同的皮层加工机制模式。

We examined central processing mechanism for speech perception and production using functional brain image such as positron emission tomography (PET) in subjects of hearing impairment and speech disorder as well as normal subjects. Postlingu ally deafened subjects indicated rather identical activation of auditory association areas with normal subjects. But, more activation was observed in cingulate gyms and supplementary motor area in deaf subjects. The brain imaging of prelingually deafened subjects showed quite different pattern. Most cases showed little activation in the auditory association areas by listening to speech sounds via cochlear implant. On the other hand, the auditory association areas were activated by lipreading in some prelingually deafened subjects. These results imply that the brain differentiation should differ according to verbal environment during speech acquisition period.As for vocalization, Broca* area, motor area, supplementary motor area, the cerebellum were important for output of speech. However, the auditory association areas were not activated during vocalization, which indicated that auditory feedback system was not needed to perform daily conversational vocalization. In contrast, when one* speech was distorted, the auditory association areas became to be activated, which implied the feedback system to repair vocalization. This situation is similar to that during speech acquisition period.In conclusion, we can observe various patterns of cortical processing mechanisms according to the situation of verbal environment.