Division of Neuropsychology, Department of Psychology, Psychological Institute, Zürich, Switzerland; Department of Psychology, Cognition, Aging, and Psychophysiology Laboratory, Concordia University, Montreal, Québec, Canada; Centre for Research on Brain, Language, and Music (CRBLM), McGill University, Montréal, Québec, Canada.
Division of Neuropsychology, Department of Psychology, Psychological Institute, Zürich, Switzerland.
Neurobiol Aging. 2019 Aug;80:116-126. doi: 10.1016/j.neurobiolaging.2019.04.017. Epub 2019 May 3.
Age-related decline in speech perception may result in difficulties partaking in spoken conversation and potentially lead to social isolation and cognitive decline in older adults. It is therefore important to better understand how age-related differences in neurostructural factors such as cortical thickness (CT) and cortical surface area (CSA) are related to neurophysiological sensitivity to speech cues in younger and older adults. Age-related differences in CT and CSA of bilateral auditory-related areas were extracted using FreeSurfer in younger and older adults with normal peripheral hearing. Behavioral and neurophysiological sensitivity to prosodic speech cues (word stress and fundamental frequency of oscillation) was evaluated using discrimination tasks and a passive oddball paradigm, while EEG was recorded, to quantify mismatch negativity responses. Results revealed (a) higher neural sensitivity (i.e., larger mismatch negativity responses) to word stress in older adults compared to younger adults, suggesting a higher importance of prosodic speech cues in the speech processing of older adults, and (b) lower CT in auditory-related regions in older compared to younger individuals, suggesting neuronal loss associated with aging. Within the older age group, less neuronal loss (i.e., higher CT) in a right auditory-related area (i.e., the supratemporal sulcus) was related to better performance in fundamental frequency discrimination, while higher CSA in left auditory-related areas was associated with higher neural sensitivity toward prosodic speech cues as evident in the mismatch negativity patterns. Overall, our results offer evidence for neurostructural changes in aging that are associated with differences in the extent to which left and right auditory-related areas are involved in speech processing in older adults. We argue that exploring age-related differences in brain structure and function associated with decline in speech perception in older adults may help develop much needed rehabilitation strategies for older adults with central age-related hearing loss.
年龄相关的言语感知能力下降可能导致老年人参与口语交流的困难，并可能导致社交孤立和认知能力下降。因此，更好地了解神经结构因素（如皮质厚度和皮质表面积）与年轻和老年成年人对言语线索的神经生理敏感性之间的年龄相关差异是很重要的。使用 FreeSurfer 在听力正常的年轻和老年成年人中提取双侧听觉相关区域的 CT 和 CSA 的年龄相关差异。使用辨别任务和被动Oddball 范式评估对韵律言语线索（词重音和基频振荡）的行为和神经生理敏感性，同时记录 EEG 以量化失匹配负波响应。结果显示：（a）与年轻成年人相比，老年成年人对词重音的神经敏感性更高（即失匹配负波响应更大），这表明韵律言语线索在老年成年人的言语处理中更为重要；（b）与年轻成年人相比，老年成年人听觉相关区域的 CT 更低，这表明与衰老相关的神经元丢失。在老年组中，右侧听觉相关区域（即颞上回）的神经元丢失较少（即 CT 较高）与基本频率辨别能力的提高有关，而左侧听觉相关区域的 CSA 较高与对韵律言语线索的神经敏感性较高有关，这在失匹配负波模式中表现明显。总的来说，我们的结果提供了与衰老相关的神经结构变化的证据，这些变化与左右听觉相关区域在老年成年人言语处理中参与程度的差异有关。我们认为，探索与老年成年人言语感知能力下降相关的大脑结构和功能的年龄相关差异，可能有助于为中心性与年龄相关的听力损失的老年成年人开发急需的康复策略。
