■人工耳蜗(CIs)是治疗严重至深度听力损失的首选方法。尽管技术进步,但CI结果的变异性仍然存在,部分归因于皮质处理的差异。研究CI用户的这些差异在技术上具有挑战性。呈现给正常听力个体的光谱退化刺激接近CI用户对中枢听觉系统的输入。这项研究使用颅内脑电图(iEEG)来研究频谱退化语音的皮层处理。
■参与者是成人神经外科癫痫患者。刺激是话语/aba/和/ada/,使用噪声声码器(1-4个频带)或在没有声编码的情况下呈现频谱降级。刺激是在两种选择的强制选择任务中呈现的。使用深度和硬膜下iEEG电极记录皮质活动。电极覆盖包括后内侧Heschl回(HGPM)的听觉核心,颞上回(STG),腹侧和背侧听觉相关区域,前额叶和感觉运动皮层。分析集中在高伽马(70-150Hz)功率增强和α(8-14Hz)抑制上。
■机会任务表现发生在1-2个光谱带中,并且对于明确的刺激接近上限。3-4个波段的性能是可变的,允许识别好的和差的表演者。任务绩效和参与者人口统计之间没有关系,听力测量,神经心理学,或临床资料。根据刺激条件之间的大小和差异确定了几种响应模式。HGPM对所有刺激反应强烈。在非核心听觉皮层中出现了对清晰语音的偏好。优秀的表演者通常对背部的所有刺激都有强烈的反应,包括后部STG,超边际,和中央前回;STG和上回的少数部位偏爱语音编码刺激。在糟糕的表演者中,反应通常仅限于清晰的言语。在表现良好的国家,阿尔法抑制更为明显。相比之下,表现不佳的人在听清晰的讲话时表现出更大的颞中后回受累。
■对噪声语音编码的响应提供了对CI结果变异性的潜在因素的见解。结果强调了表现良好和表现较差的背侧和腹侧神经处理平衡的差异,确定可能具有诊断和预后效用的特定皮质区域,并提出了基于神经调节的CI康复策略的潜在目标。
UNASSIGNED: Cochlear implants (CIs) are the treatment of choice for severe to profound hearing loss. Variability in CI outcomes remains despite advances in technology and is attributed in part to differences in cortical processing. Studying these differences in CI users is technically challenging. Spectrally degraded stimuli presented to normal-hearing individuals approximate input to the central auditory system in CI users. This study used intracranial electroencephalography (
iEEG) to investigate cortical processing of spectrally degraded speech.
UNASSIGNED: Participants were adult neurosurgical epilepsy patients. Stimuli were utterances /aba/ and /ada/, spectrally degraded using a noise vocoder (1-4 bands) or presented without vocoding. The stimuli were presented in a two-alternative forced choice task. Cortical activity was recorded using depth and subdural
iEEG electrodes. Electrode coverage included auditory core in posteromedial Heschl\'s gyrus (HGPM), superior temporal gyrus (STG), ventral and dorsal auditory-related areas, and prefrontal and sensorimotor cortex. Analysis focused on high gamma (70-150 Hz) power augmentation and alpha (8-14 Hz) suppression.
UNASSIGNED: Chance task performance occurred with 1-2 spectral bands and was near-ceiling for clear stimuli. Performance was variable with 3-4 bands, permitting identification of good and poor performers. There was no relationship between task performance and participants demographic, audiometric, neuropsychological, or clinical profiles. Several response patterns were identified based on magnitude and differences between stimulus conditions. HGPM responded strongly to all stimuli. A preference for clear speech emerged within non-core auditory cortex. Good performers typically had strong responses to all stimuli along the dorsal stream, including posterior STG, supramarginal, and precentral gyrus; a minority of sites in STG and supramarginal gyrus had a preference for vocoded stimuli. In poor performers, responses were typically restricted to clear speech. Alpha suppression was more pronounced in good performers. In contrast, poor performers exhibited a greater involvement of posterior middle temporal gyrus when listening to clear speech.
UNASSIGNED: Responses to noise-vocoded speech provide insights into potential factors underlying CI outcome variability. The results emphasize differences in the balance of neural processing along the dorsal and ventral stream between good and poor performers, identify specific cortical regions that may have diagnostic and prognostic utility, and suggest potential targets for neuromodulation-based CI rehabilitation strategies.