McCullagh Jennifer, Shinn Jennifer B
Southern Connecticut State University, New Haven, CT.
University of Kentucky Medical Center, Lexington, KY.
J Am Acad Audiol. 2018 Nov/Dec;29(10):909-916. doi: 10.3766/jaaa.17077.
Older adults often report difficulty hearing in background noise which is not completely attributable to peripheral hearing loss. Although age-related declines in cognition and hearing in background noise occur, the underlying age-related changes in processing of auditory stimuli in background noise has yet to be fully understood. The auditory P300 has the potential to elucidate the effects of age on auditory and cognitive processing of stimuli in background noise, but additional research is warranted.
The purpose of this study was to investigate age-related differences in cognitive processing of auditory stimuli by evoking the auditory P300 at multiple signal-to-noise ratios (SNRs).
A two-group, repeated measures study design was used.
A convenience sample of 35 participants, 15 older adults (mean age of 66.4 yr) and 20 younger adults (mean age of 21.1 yr), participated in the study. All participants had negative otologic and neurological histories.
The auditory P300 was evoked using an oddball paradigm with 500 (frequent) and 1000 Hz (target) tonal stimuli in quiet and in the presence of background noise at +20, +10, and 0 SNRs. P300 amplitudes and latencies were measured in each condition for every participant. Repeated measures analyses of variance were conducted for the amplitude and latency measures of the P300 for each group.
Results from this study demonstrated P300 latencies were significantly longer in older adults in noise at the most challenging condition (0 SNR) compared with the quiet condition and between the +10 SNR and 0 SNR conditions. Although older adults had significantly longer P300 latencies compared with younger adults, no significant group by listening condition interaction existed. No significant P300 amplitude differences were found for group, noise, or group × listening condition interactions.
Results provide evidence that auditory cortical processing, regardless of age, is poorer at more difficult SNRs. However, results also demonstrate that older adults perform significantly poorer than younger adults. This supports the notion that some degree of age-related decline in synchronous firing and rate of transmission of the auditory cortical neurons contributing to the auditory P300 exists. Studies are needed to further understand the impact of noise on auditory cortical processing across populations.
老年人经常报告在背景噪声中听力困难，这并不完全归因于外周听力损失。尽管与年龄相关的认知和背景噪声中听力下降会发生，但在背景噪声中听觉刺激处理方面与年龄相关的潜在变化尚未完全了解。听觉P300有潜力阐明年龄对背景噪声中刺激的听觉和认知处理的影响，但仍需要更多研究。
本研究的目的是通过在多个信噪比（SNR）下诱发听觉P300来研究听觉刺激认知处理中的年龄相关差异。
采用两组重复测量研究设计。
35名参与者的便利样本，15名老年人（平均年龄66.4岁）和20名年轻人（平均年龄21.1岁）参与了研究。所有参与者均有阴性耳科和神经病史。
使用奇偶数范式，在安静环境以及存在背景噪声（信噪比分别为+20、+10和0）的情况下，用500Hz（频繁出现）和1000Hz（目标）音调刺激诱发听觉P300。测量每个参与者在每种条件下的P300波幅和潜伏期。对每组P300的波幅和潜伏期测量进行重复测量方差分析。
本研究结果表明，在最具挑战性的条件（0 SNR）下，老年人在噪声环境中的P300潜伏期明显长于安静环境，以及在+10 SNR和0 SNR条件之间。尽管老年人的P300潜伏期明显长于年轻人，但在聆听条件方面不存在显著的组间交互作用。在组、噪声或组×聆听条件交互作用方面未发现显著的P300波幅差异。
结果提供了证据，表明无论年龄大小，在更困难的信噪比下听觉皮层处理能力都会变差。然而，结果也表明老年人的表现明显比年轻人差。这支持了这样一种观点，即存在一定程度的与年龄相关的听觉皮层神经元同步放电和传输速率下降，这会影响听觉P300。需要进一步研究以了解噪声对不同人群听觉皮层处理的影响。
