Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
Hear Res. 2021 Mar 15;402:107991. doi: 10.1016/j.heares.2020.107991. Epub 2020 May 11.
Within the cochlea, broadband sounds like speech and music are filtered into a series of narrowband signals, each with a relatively slowly varying envelope (ENV) imposed on a rapidly oscillating carrier (the temporal fine structure, TFS). Information about ENV is conveyed by the timing and short-term rate of action potentials in the auditory nerve while information about TFS is conveyed by synchronization of action potentials to a specific phase of the waveform in the cochlea (phase locking). This paper describes the effects of age and hearing loss on the binaural processing of ENV and TFS information, i.e. on the processing of differences in ENV and TFS at the two ears. The binaural processing of TFS information is adversely affected by both hearing loss and increasing age. The binaural processing of ENV information deteriorates somewhat with increasing age but is only slightly affected by hearing loss. The reduced TFS processing abilities found for older/hearing-impaired subjects may partially account for the difficulties that such subjects experience in complex listening situations when the target speech and interfering sounds come from different directions in space.
在耳蜗内，宽带声音（如语音和音乐）被过滤成一系列窄带信号，每个信号都有一个相对缓慢变化的包络（ENV）施加在快速振荡载波（时频精细结构，TFS）上。听觉神经中动作电位的时间和短期发放率传递关于 ENV 的信息，而动作电位对耳蜗中波形特定相位的同步（相位锁定）传递关于 TFS 的信息。本文描述了年龄和听力损失对 ENV 和 TFS 信息的双耳处理的影响，即对两耳之间 ENV 和 TFS 差异的处理的影响。TFS 信息的双耳处理受到听力损失和年龄增长的不利影响。随着年龄的增长，ENV 信息的双耳处理会略有恶化，但受听力损失的影响很小。对于年龄较大/听力受损的受试者，发现 TFS 处理能力降低，这可能部分解释了这些受试者在目标语音和干扰声音来自空间不同方向的复杂聆听情况下所遇到的困难。
