Tadros Sherif F, Frisina Susan T, Mapes Frances, Kim SungHee, Frisina D Robert, Frisina Robert D
International Center for Hearing and Speech Research, National Technical Institute for the Deaf, Rochester Institute of Technology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Audiol Neurootol. 2005 Jan-Feb;10(1):44-52. doi: 10.1159/000082307.
In young adults with normal hearing, the right ear is more sensitive than the left to simple sounds (peripheral right-ear advantage) and to processing complex sounds such as speech (central right-ear advantage). In the present investigation, the effects of hearing loss and aging on this auditory asymmetry were examined at both peripheral and central levels. Audiograms and transient evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission amplitudes were used to assess cochlear function. The contralateral suppression of TEOAEs was measured to assess the medial olivocochlear efferent system. The Hearing in Noise Test (HINT; binaural speech) was conducted to assess higher central auditory function. A group of aged subjects with normal hearing (flat audiograms) were compared to a group of aged subjects with sloping audiograms (presbycusis). At the cochlear (peripheral) level, the normal hearing group showed significantly higher otoacoustic emission amplitudes for the right ear compared to the left ear, which is consistent with the right-ear dominance normally seen in young adults. However, this finding was reversed in the presbycusic group that showed higher left-ear emission amplitudes. At the brainstem level, the amplitudes of TEOAE contralateral suppression were small and no significant difference was found between the right and left ears in both groups. On the contrary, HINT results showed a continuous dominance of the right ear (left hemisphere) in both groups, which was consistent with previous reports showing that the right hemisphere is more affected by age than the left hemisphere.
在听力正常的年轻人中，右耳对简单声音（外周右耳优势）以及对诸如语音等复杂声音的处理（中枢右耳优势）比左耳更敏感。在本研究中，在周围和中枢水平上研究了听力损失和衰老对这种听觉不对称性的影响。听力图、瞬态诱发耳声发射（TEOAE）和畸变产物耳声发射幅度用于评估耳蜗功能。测量TEOAE的对侧抑制以评估内侧橄榄耳蜗传出系统。进行噪声环境下言语听力测试（HINT；双耳言语）以评估更高水平的中枢听觉功能。将一组听力正常的老年受试者（听力图平坦）与一组听力图呈斜坡状的老年受试者（老年性耳聋）进行比较。在耳蜗（外周）水平，听力正常组右耳的耳声发射幅度明显高于左耳，这与年轻人中常见的右耳优势一致。然而，在老年性耳聋组中这一发现相反，该组左耳发射幅度更高。在脑干水平，两组的TEOAE对侧抑制幅度都很小，且左右耳之间未发现显著差异。相反，HINT结果显示两组中右耳（左半球）持续占优势，这与先前的报告一致，即右半球比左半球受年龄影响更大。
