Song Jae-Jin, Vanneste Sven, Lazard Diane S, Van de Heyning Paul, Park Joo Hyun, Oh Seung Ha, De Ridder Dirk
Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
Hum Brain Mapp. 2015 May;36(5):1982-94. doi: 10.1002/hbm.22750. Epub 2015 Jan 24.
Previous positron emission tomography (PET) studies have shown that various cortical areas are activated to process speech signal in cochlear implant (CI) users. Nonetheless, differences in task dimension among studies and low statistical power preclude from understanding sound processing mechanism in CI users. Hence, we performed activation likelihood estimation meta-analysis of PET studies in CI users and normal hearing (NH) controls to compare the two groups. Eight studies (58 CI subjects/92 peak coordinates; 45 NH subjects/40 peak coordinates) were included and analyzed, retrieving areas significantly activated by lexical and nonlexical stimuli. For lexical and nonlexical stimuli, both groups showed activations in the components of the dual-stream model such as bilateral superior temporal gyrus/sulcus, middle temporal gyrus, left posterior inferior frontal gyrus, and left insula. However, CI users displayed additional unique activation patterns by lexical and nonlexical stimuli. That is, for the lexical stimuli, significant activations were observed in areas comprising salience network (SN), also known as the intrinsic alertness network, such as the left dorsal anterior cingulate cortex (dACC), left insula, and right supplementary motor area in the CI user group. Also, for the nonlexical stimuli, CI users activated areas comprising SN such as the right insula and left dACC. Previous episodic observations on lexical stimuli processing using the dual auditory stream in CI users were reconfirmed in this study. However, this study also suggests that dual-stream auditory processing in CI users may need supports from the SN. In other words, CI users need to pay extra attention to cope with degraded auditory signal provided by the implant.
以往的正电子发射断层扫描（PET）研究表明，人工耳蜗（CI）使用者在处理语音信号时，多个皮质区域会被激活。尽管如此，研究之间任务维度的差异以及低统计效力阻碍了我们对CI使用者声音处理机制的理解。因此，我们对CI使用者和正常听力（NH）对照者的PET研究进行了激活可能性估计荟萃分析，以比较两组。纳入并分析了八项研究（58名CI受试者/92个峰值坐标；45名NH受试者/40个峰值坐标），检索出由词汇和非词汇刺激显著激活的区域。对于词汇和非词汇刺激，两组在双流模型的组成部分中均表现出激活，如双侧颞上回/沟、颞中回、左侧额下回后部和左侧脑岛。然而，CI使用者在词汇和非词汇刺激下表现出额外独特的激活模式。也就是说，对于词汇刺激，在CI使用者组中，包括突显网络（SN）（也称为内在警觉网络）的区域观察到显著激活，如左侧背侧前扣带回皮质（dACC）、左侧脑岛和右侧辅助运动区。此外，对于非词汇刺激，CI使用者激活了包括SN的区域，如右侧脑岛和左侧dACC。本研究再次证实了以往关于CI使用者使用双听觉流处理词汇刺激的情景观察。然而，本研究还表明，CI使用者的双流听觉处理可能需要突显网络的支持。换句话说，CI使用者需要格外注意以应对植入物提供的退化听觉信号。
