Campbell Julia, Bean Connor, LaBrec Alison
Department of Communication Sciences and Disorders; Central Sensory Processes Laboratory, University of Texas at Austin, Austin, Texas, USA.
Audiol Res. 2018 Oct 2;8(2):214. doi: 10.4081/audiores.2018.214.
Decreased central inhibition, possibly related to hearing loss, may contribute to chronic tinnitus. However, many individuals with normal hearing thresholds report tinnitus, suggesting that the percept in this population may arise from sources other than peripheral deafferentation. One measure of inhibition is sensory gating. Sensory gating involves the suppression of non-novel input, and is measured through cortical auditory evoked potential (CAEP) responses to paired stimuli. In typical gating function, amplitude suppression is observed in the second CAEP response when compared to the first CAEP response, illustrating inhibitory activity. Using this measure, we investigated central inhibitory processes in normal hearing young adults with and without mild tinnitus to determine whether inhibition may be a contributing factor to the tinnitus percept. Results showed that gating function was impaired in the tinnitus group, with the CAEP Pa component significantly correlated with tinnitus severity. Further exploratory analyses were conducted to evaluate variability in gating function within the tinnitus group, and findings showed that high CAEP amplitude suppressors demonstrated gating performance comparable to adults without tinnitus, while low amplitude suppressors exhibited atypical gating function.
中枢抑制的降低可能与听力损失有关，可能会导致慢性耳鸣。然而，许多听力阈值正常的人也报告有耳鸣，这表明该人群中的耳鸣感知可能源于外周去传入以外的其他来源。抑制的一种测量方法是感觉门控。感觉门控涉及对非新颖输入的抑制，并通过对配对刺激的皮质听觉诱发电位（CAEP）反应来测量。在典型的门控功能中，与第一个CAEP反应相比，在第二个CAEP反应中观察到幅度抑制，这说明了抑制活动。利用这一测量方法，我们研究了有和没有轻度耳鸣的听力正常的年轻成年人的中枢抑制过程，以确定抑制是否可能是耳鸣感知的一个促成因素。结果显示，耳鸣组的门控功能受损，CAEP的Pa成分与耳鸣严重程度显著相关。我们进行了进一步的探索性分析，以评估耳鸣组内门控功能的变异性，结果显示，高CAEP幅度抑制者的门控表现与没有耳鸣的成年人相当，而低幅度抑制者则表现出非典型的门控功能。
