Manchester Centre for Audiology and Deafness, School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.
Manchester Centre for Audiology and Deafness, School of Health Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.
Hear Res. 2019 Feb;372:10-16. doi: 10.1016/j.heares.2018.01.016. Epub 2018 Feb 2.
Animal studies have demonstrated that unilateral hearing loss can induce changes in neural response amplitude of the mature central auditory system (CAS). However, there is limited physiological evidence of these neural gain changes in the auditory cortex of human adults. The present study investigated the impact of chronic, unilateral conductive hearing impairment on cortical auditory evoked potentials (CAEPs) recorded from 15 adults (21-65 years old) in response to a 1 kHz tone (80 ms duration) presented to the impaired ear via a bone conduction transducer. The amplitude and latency of the main CAEP components were compared to those obtained from normal hearing age-matched control participants. Both P1-N1 and N1-P2 amplitudes were significantly larger in the hearing impaired relative to the control participants. Differences between groups in the mean latencies of P1, N1, and P2 were not statistically significant. These results are the first to provide direct evidence of increased neural response amplitude in the adult human auditory cortex in the presence of unilateral conductive hearing loss. Importantly, the study shows that central gain changes are a direct result of deprivation of sound rather than cochlear or neural pathology.
动物研究表明，单侧听力损失可引起成熟中枢听觉系统（CAS）的神经反应幅度变化。然而，在成人听觉皮层中，这些神经增益变化的生理证据有限。本研究调查了慢性单侧传导性听力障碍对 15 名成年人（21-65 岁）的皮质听觉诱发电位（CAEP）的影响，这些成年人通过骨导换能器接受受损耳的 1 kHz 音调（80 ms 时长）刺激。将主要 CAEP 成分的幅度和潜伏期与正常听力年龄匹配的对照组的结果进行了比较。与对照组相比，听力受损者的 P1-N1 和 N1-P2 幅度明显更大。组间 P1、N1 和 P2 的平均潜伏期差异无统计学意义。这些结果首次提供了直接证据，证明在存在单侧传导性听力损失的情况下，成人听觉皮层的神经反应幅度增加。重要的是，该研究表明中枢增益变化是声音剥夺的直接结果，而不是耳蜗或神经病理学的结果。
