Starr A, Picton T W, Sininger Y, Hood L J, Berlin C I
Department Neurology, University of California, Irvine 92717, USA.
Brain. 1996 Jun;119 ( Pt 3):741-53. doi: 10.1093/brain/119.3.741.
Ten patients presented as children or young adults with hearing impairments that, by behavioural and physiological testing, were compatible with a disorder of the auditory portion of the VIII cranial nerve. Evidence of normal cochlear outer hair cell function was provided by preservation of otoacoustic emissions and cochlear microphonics in all of the patients. Auditory brainstem potentials showed evidence of abnormal auditory pathway function beginning with the VIII nerve: the potentials were absent in nine patients and severely distorted in one patient. Auditory brainstem reflexes (middle ear muscles; crossed suppression of otoacoustic emissions) were absent in all of the tested patients. Behavioural audiometric testing showed a mild to moderate elevation of pure tone threshold in nine patients. The extent of the hearing loss, if due to cochlear receptor damage, should not have resulted in the loss of auditory brainstem potentials. The shape of the pure tone loss varied, being predominantly low frequency in five patients, flat across all frequencies in three patients and predominantly high frequency in two patients. Speech intelligibility was tested in eight patients, and in six was affected out of proportion to what would have been expected if the pure tone loss were of cochlear origin. The patients were otherwise neurologically normal when the hearing impairment was first manifest. Subsequently, eight of these patients developed evidence for a peripheral neuropathy. The neuropathy was hereditary in three and sporadic in five. We suggest that this type of hearing impairment is due to a disorder of auditory nerve function and may have, as one of its causes, a neuropathy of the auditory nerve, occurring either in isolation or as part of a generalized neuropathic process.
10名患者在儿童期或青年期出现听力障碍，通过行为学和生理学测试，这些障碍与第八颅神经听觉部分的疾病相符。所有患者均保留耳声发射和耳蜗微音电位，证明耳蜗外毛细胞功能正常。听性脑干电位显示从第八神经开始听觉通路功能异常：9名患者电位缺失，1名患者电位严重畸变。所有受试患者的听性脑干反射（中耳肌肉；耳声发射的交叉抑制）均缺失。行为测听测试显示9名患者纯音阈值轻度至中度升高。如果听力损失是由于耳蜗感受器损伤所致，其程度不应导致听性脑干电位丧失。纯音损失的形态各异，5名患者以低频为主，3名患者各频率平坦，2名患者以高频为主。对8名患者进行了言语清晰度测试，其中6名患者的言语清晰度受到的影响与纯音损失源于耳蜗时预期的情况不成比例。听力障碍首次出现时，这些患者在其他方面神经功能正常。随后，其中8名患者出现了周围神经病变的证据。3名患者的神经病变为遗传性，5名患者为散发性。我们认为，这种类型的听力障碍是由于听觉神经功能障碍所致，其原因之一可能是听觉神经病变，可单独发生或作为全身性神经病变过程的一部分。
