The University of Melbourne, Department of Audiology & Speech Pathology, Parkville, Melbourne, Australia.
Neuroscience. 2012 Dec 13;226:227-35. doi: 10.1016/j.neuroscience.2012.08.054. Epub 2012 Sep 13.
Auditory neuropathy disrupts the neural representation of sound and may therefore impair processes contingent upon inter-aural integration. The aims of this study were to investigate binaural auditory processing in individuals with axonal (Friedreich ataxia) and demyelinating (Charcot-Marie-Tooth disease type 1A) auditory neuropathy and to evaluate the relationship between the degree of auditory deficit and overall clinical severity in patients with neuropathic disorders. Twenty-three subjects with genetically confirmed Friedreich ataxia and 12 subjects with Charcot-Marie-Tooth disease type 1A underwent psychophysical evaluation of basic auditory processing (intensity discrimination/temporal resolution) and binaural speech perception assessment using the Listening in Spatialized Noise test. Age, gender and hearing-level-matched controls were also tested. Speech perception in noise for individuals with auditory neuropathy was abnormal for each listening condition, but was particularly affected in circumstances where binaural processing might have improved perception through spatial segregation. Ability to use spatial cues was correlated with temporal resolution suggesting that the binaural-processing deficit was the result of disordered representation of timing cues in the left and right auditory nerves. Spatial processing was also related to overall disease severity (as measured by the Friedreich Ataxia Rating Scale and Charcot-Marie-Tooth Neuropathy Score) suggesting that the degree of neural dysfunction in the auditory system accurately reflects generalized neuropathic changes. Measures of binaural speech processing show promise for application in the neurology clinic. In individuals with auditory neuropathy due to both axonal and demyelinating mechanisms the assessment provides a measure of functional hearing ability, a biomarker capable of tracking the natural history of progressive disease and a potential means of evaluating the effectiveness of interventions.
听觉神经病变会破坏声音的神经表示，因此可能会损害依赖于两耳间整合的过程。本研究的目的是研究具有轴索性（弗里德里希共济失调）和脱髓鞘性（Charcot-Marie-Tooth 病 1A 型）听觉神经病的个体的双耳听觉处理，并评估听觉缺陷程度与神经病变患者的整体临床严重程度之间的关系。 23 名经基因证实的弗里德里希共济失调患者和 12 名 Charcot-Marie-Tooth 病 1A 型患者接受了基本听觉处理（强度辨别/时间分辨率）和双耳言语感知评估的心理物理学评估，使用 Listening in Spatialized Noise 测试。还测试了年龄、性别和听力匹配的对照组。对于听觉神经病患者，噪声中的言语感知在每种听力条件下均异常，但在双耳处理可能通过空间分离改善感知的情况下尤其受到影响。使用空间线索的能力与时间分辨率相关，这表明双耳处理缺陷是由于左右听神经中计时线索的表示紊乱所致。空间处理也与整体疾病严重程度（通过弗里德里希共济失调评定量表和 Charcot-Marie-Tooth 神经病评分测量）相关，这表明听觉系统中神经功能障碍的程度准确反映了广义的神经病变变化。双耳言语处理的测量具有在神经病学临床应用的潜力。在由于轴索和脱髓鞘机制引起的听觉神经病患者中，该评估提供了功能听力能力的衡量标准，是能够跟踪疾病自然史的生物标志物，也是评估干预措施有效性的潜在手段。
