Basic and clinical investigation of speech processing mechanism for the improvement of cochlear implant

1)语言知觉(1)语言在内耳的加工(耳蜗图)：正常受试者在元音和CV音节发音的头部以及元音的连续部分出现大写现象，而在CV音节的元音起始处没有大写现象。在一些感音神经性耳聋患者中，这些帽子缺失。(2)口语皮层加工机制(PET、MEG、MRI)：PET研究表明，正常受试者两侧大脑半球的听觉关联区主要处理来自对侧耳的语言输入，语音激活听觉关联区，而噪声引起的rCBF仅在人工耳蜗者初级听区增加。在语前聋患者中，甚至在…中也不存在听觉关联区的激活更多的是语音刺激，这表明没有语音刺激，语言的大脑皮层网络就不会发育。利用脑磁图，我们发现在正常受试者中，语音比噪声更能激活听觉皮质，并证实了改变语音和噪声的皮层机制。我们还发现，在正常受试者中，对侧大脑半球的反应潜伏期早于声音输入的同侧大脑半球。相反，在单侧耳聋患者中，没有观察到这种偏侧性。这些结果表明单侧听力丧失后皮层网络的重组。2)皮层的语音产生机制我们发现，正常成人受试者发出熟悉的语音时，没有在听觉关联区监测自己的声音，但当自己的声音听起来与发音的声音不同时，听觉言语反馈变得活跃。这些结果表明，大脑皮质存在完全的后天语音输出机制，以及利用听觉言语反馈系统矫正发声和发音的机制。在这项研究中，我们确认了辅助运动区对编程发音运动的重要性，以及小脑对发声调节的重要性。Wa还证明了大脑皮质处理语音产生的时间过程是连续的和平行的，这证明了大脑的合理功能。较少

1) Perception of language(1) processing of language in inner ear (Electrocochleography) : In normal subjects, CAPs were observed at the head of vowel and CV syllable sounds as well as at the continuous part of vowels, while CAPs were absent at the onset of vowel in CV syllable. These CAPs were lack in some sensorineural hearing loss patients. We confirmed the importance of temporal information made in inner ear for perception of language, and developed digital hearing aid based on amplification with flexible time window.(2) cortical processing mechnism for spoken language (PET,MEG,MRI) : PET studies showed that the auditory association areas in each hemisphere mainly processed language input from the contrlateral ear in normal subjects, and that speech sounds activated the auditory association areas while noise induced rCBF increase only in the primary auditory area in cochlear implant users. In prelingual deaf patiente, the activation of the auditory association areas was absent even … More with speech sounds stimulation, which indicated that the cortical network for language was not developed without speech sound stimuli. Using MEG, we found that the auditory cortices were more activated by speech sound than by noise in normal subjects, and confirmed the cortical mechanism to alter speech and noise. We also found that the response in the contralateral hemisphere appeared earlier in latency than that in the ipsilateral one to the ear where sounds were input in normal subjects. On the contrary, in unilateral deaf patients, this laterality was not observed. These results showed the reorganization of cortical network after unilateral hearing loss.2) cortical mechanisms for speech productionWe found that normal adult subjects vocalized familiar speech without monitoring their own voices in the auditory association areas, but that when the own voice sounded different to the articulated one, the auditory verbal feedback became active. These results indicate that there exist fully acquired speech output mechanism in cortex as well as the mechanism for correction of vocalization and articulation using auditory verbal feedback system. In this study, we confirmed the importance of the supplementary motor area for programing the articulatory movement and the cerebellum for the adjustment of vocalization. Wa also proved the time course of cortical processing for speech production to be sequential and parallel, which demonstrated the reasonable function of brain. Less