Jagoda Laura, Giroud Nathalie, Neff Patrick, Kegel Andrea, Kleinjung Tobias, Meyer Martin
Division of Neuropsychology, Department of Psychology, University of Zurich, Zurich, Switzerland.
Cognition Aging and Psychophysiology Laboratory, Department of Psychology, Concordia University, Montreal, Canada.
Hear Res. 2018 Sep;367:48-58. doi: 10.1016/j.heares.2018.07.001. Epub 2018 Jul 5.
Individuals suffering from tinnitus often complain about difficulties understanding speech in noisy environments even in the absence of a peripheral hearing loss. This EEG study aimed to investigate whether aspects of phonetic perception are affected by the experience of tinnitus. We examined a sample of individuals with chronic, subjective tinnitus (n = 30, age range 30-50 yrs.), who underwent behavioural screening (standard tinnitus questionnaires) and comprehensive audiometric testing that covered peripheral and central hearing abilities (pure tone audiometry, suprathreshold audiometry (frequency selectivity and temporal compression), and speech in noise performance). In addition, participants performed a phoneme discrimination task embedded in an active oddball paradigm, while auditory evoked potentials (AEPs) were recorded. In particular, we aimed to investigate if reported speech difficulties in chronic tinnitus trace back to deficits in more elementary speech processes such as phonetic processing. Furthermore, we explored whether central hearing loss and tinnitus' psychometric profile may account for deficiencies in speech perception. The analysis of behavioural and audiometric data showed indications of mild to moderate symptoms of tinnitus distress when peripheral hearing loss was not in evidence. Nevertheless, tinnitus distress was negatively related to speech in noise performance which may be indicative of a lack of inhibitory competence. We further observed an effect of tinnitus distress on phoneme discrimination. More precisely, higher tinnitus distress was associated with higher accuracy and longer reaction times, while the effect on reaction times was mediated by the individual N2 ERP peak amplitudes. Our results suggest that tinnitus clearly interacts with the central auditory system in that responsiveness to salient input changes as a function of tinnitus-related distress, irrespective of peripheral hearing loss. Akin to individuals with higher psychological stress, persons with increased tinnitus-related distress demonstrate higher sensitivity during auditory processing. Taken together, we interpret our findings in light of a Bayesian approach (Sedley et al., 2016). According to this view, tinnitus distress-related factors (e.g., attention, stress) influence the excitability of the central auditory system and this, in turn, affects the sensory precision of inflowing auditory input, including spoken language.
患有耳鸣的人常常抱怨，即使没有外周听力损失，在嘈杂环境中理解言语也有困难。这项脑电图研究旨在调查语音感知方面是否会受到耳鸣体验的影响。我们研究了一组患有慢性主观性耳鸣的个体（n = 30，年龄范围30 - 50岁），他们接受了行为筛查（标准耳鸣问卷）以及涵盖外周和中枢听力能力的全面听力测试（纯音听力测定、阈上听力测定（频率选择性和时间压缩）以及噪声中的言语表现）。此外，参与者在主动奇偶数范式中执行音素辨别任务，同时记录听觉诱发电位（AEP）。特别是，我们旨在调查慢性耳鸣中报告的言语困难是否可追溯到更基本的言语过程（如语音处理）中的缺陷。此外，我们探讨了中枢听力损失和耳鸣的心理测量特征是否可以解释言语感知方面的缺陷。行为和听力数据的分析表明，在外周听力损失不明显时，有轻度至中度耳鸣困扰症状的迹象。然而，耳鸣困扰与噪声中的言语表现呈负相关，这可能表明缺乏抑制能力。我们还观察到耳鸣困扰对音素辨别有影响。更确切地说，较高的耳鸣困扰与较高的准确性和较长的反应时间相关，而对反应时间的影响由个体N2 ERP峰值幅度介导。我们的结果表明，耳鸣与中枢听觉系统明显相互作用，即对显著输入的反应性会随着与耳鸣相关的困扰而变化，而与外周听力损失无关。与心理压力较高的个体类似，与耳鸣相关困扰增加的人在听觉处理过程中表现出更高的敏感性。综上所述，我们根据贝叶斯方法（塞德利等人，2016年）来解释我们的发现。根据这一观点，与耳鸣困扰相关的因素（如注意力、压力）会影响中枢听觉系统的兴奋性，进而影响流入的听觉输入（包括口语）的感觉精度。
