Cortical Correlates of Binaural Temporal Processing Deficits in Older Adults.
Cortical Correlates of Binaural Temporal Processing Deficits in Older Adults.
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DOI：
10.1097/aud.0000000000000518
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发表时间：
2018
期刊：
影响因子：
3.7
通讯作者：
Eddins DA
中科院分区：
文献类型：
--
作者：
Eddins AC;Eddins DA
本研究采用双耳掩蔽水平差（BMLD）范式，对青年和老年人的双耳时间加工进行了评估。使用行为和电生理的措施，在同一个听众，一系列的刺激操作被用来评估双耳的时间精细结构和时间包络线索的相对贡献。我们评估了以下假设：BMLD任务中与年龄相关的下降与时间精细结构的相关性比与包络线索的相关性更强，行为测量中与年龄相关的下降与皮质听觉诱发电位（CAEP）测量相关。30名成年人参加了这项研究，其中包括10名年轻的听力正常，10名老年听力正常，10名老年听力受损，双侧对称，轻度至中度感音神经性听力损失（SNHL）。在连续性双耳（No）窄带噪声（50 Hz宽）掩蔽下，测量双耳（So）和双耳两分（Sπ）音调信号的行为和CAEP阈值。时间包络线索操纵使用两种不同的窄带掩蔽;高斯噪声（GN）与强大的包络波动和低噪声噪声（LNN）与最小的包络波动。通过改变信号频率（500 Hz或4000 Hz）来控制使用时间精细结构线索的潜力，从而依赖于锁相随频率增加而自然下降。行为和CAEP阈值在diotic条件下的各组之间相似，而在两分条件下的掩蔽释放对于年轻参与者比老年参与者更大。在所有参与者中，GN的BMLD大于LNN，500 Hz条件下的BMLD大于4000 Hz条件下的BMLD，其中包络和精细结构线索分别最突出。特定的年龄相关的差异，表现为500赫兹的双耳两分条件GN和LNN，反映减少双耳时间精细结构编码。没有显着的年龄效应，观察到4000赫兹的双耳两分条件下，在这些条件下，类似的使用双耳时间包络线索跨年龄。对于所有的群体，阈值和派生的BMLD值使用的行为和CAEP方法得到了强烈的相关性，支持的概念，CAEP措施可能是有用的年龄相关的变化双耳时间处理的客观指标。这些结果表明，在双耳时间的精细结构线索与保留的时间包络编码，是类似的，没有轻度至中度的外周听力损失的处理与年龄相关的下降。这种与年龄相关的变化可以通过年轻人和老年人的行为和CAEP测量可靠地索引。
This study was designed to evaluate binaural temporal processing in young and older adults using a binaural masking level difference (BMLD) paradigm. Using behavioral and electrophysiological measures within the same listeners, a series of stimulus manipulations was used to evaluate the relative contribution of binaural temporal fine structure and temporal envelope cues. We evaluated the hypotheses that age-related declines in the BMLD task would be more strongly associated with temporal fine structure than envelope cues and that age-related declines in behavioral measures would be correlated with cortical auditory evoked potential (CAEP) measures. Thirty adults participated in the study, including ten young normal-hearing, ten older normal-hearing, and ten older hearing-impaired with bilaterally symmetric, mild to moderate sensorineural hearing loss (SNHL). Behavioral and CAEP thresholds were measured for diotic (So) and dichotic (Sπ) tonal signals presented in continuous diotic (No) narrowband noise (50-Hz wide) maskers. Temporal envelope cues were manipulated by using two different narrowband maskers; Gaussian noise (GN) with robust envelope fluctuations and low-noise noise (LNN) with minimal envelope fluctuations. The potential to use temporal fine structure cues was controlled by varying the signal frequency (500 Hz or 4000 Hz), thereby relying on the natural decline in phase-locking with increasing frequency. Behavioral and CAEP thresholds were similar across groups for diotic conditions, while the masking release in dichotic conditions was larger for younger than older participants. Across all participants, BMLDs were larger for GN than LNN and for 500- than 4000-Hz conditions, where envelope and fine structure cues were most salient, respectively. Specific age-related differences were demonstrated for 500-Hz dichotic conditions in GN and LNN, reflecting reduced binaural temporal fine structure coding. No significant age effects were observed for 4000-Hz dichotic conditions, consistent with similar use of binaural temporal envelope cues across age in these conditions. For all groups, thresholds and derived BMLD values obtained using the behavioral and CAEP methods were strongly correlated, supporting the notion that CAEP measures may be useful as an objective index of age-related changes binaural temporal processing. These results demonstrate an age-related decline in the processing of binaural temporal fine structure cues with preserved temporal envelope coding that was similar with and without mild-to-moderate peripheral hearing loss. Such age-related changes can be reliably indexed by both behavioral and CAEP measures in young and older adults.