Di Nardo W, Ghirlanda G, Paludetti G, Cercone S, Saponara C, Del Ninno M, Di Girolamo S, Magnani P, Di Leo M A
Department of Otorhinolaryngology, Catholic University, Rome, Italy.
Diabetes Care. 1998 Aug;21(8):1317-21. doi: 10.2337/diacare.21.8.1317.
To provide information about possible subclinical damage of the cochlear outer hair cells (OHCs) by means of transiently evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) in subjects with IDDM.
TEOAEs and DPOAEs were recorded in 47 IDDM patients with normal hearing and in age- and sex-matched nondiabetic subjects. Peripheral neuropathy was diagnosed by nerve conduction velocity (NCV) at the peroneal and surral nerves.
A subclinical peripheral neuropathy was found in 15 diabetic patients. Mean TEOAE amplitude was found to be significantly reduced in diabetic patients with a reduced NCV (7.6 +/- 3.2 dB; Scheffé's test: P = 0.03), but not in those without neuropathy (9.5 +/- 4.3 dB), with respect to control subjects (11 +/- 3.1 dB). Neuropathic patients also showed mean reduced DPOAE amplitude values in the region of middle and high frequencies from 1,306 to 5,200 Hz (P < 0.05), whereas no difference was found at the lowest-frequency amplitudes. A frequency-selective reduction of DPOAEs was also found in non-neuropathic patients (P < 0.05) in the region of higher frequencies at 3,284, 4,126, and 5,200 Hz compared with control subjects. No correlations were found among duration of diabetes, HbA1c values, TEOAEs and DPOAEs.
Our results suggest that IDDM patients show an early abnormality of the micromechanical properties of the OHCs. In IDDM patients without a subclinical peripheral neuropathy, damage is limited to the higher frequencies and can be detected only by DPOAEs, whereas in IDDM patients with neuropathy, damage also involves the middle range of frequencies and can be detected by TEOAEs and DPOAEs. Therefore, DPOAEs seem to be able to detect the earliest cochlear selective-frequency dysfunction in IDDM patients without peripheral neuropathy. DPOAEs appear to be of greater clinical interest than TEOAEs; the former seem to be frequency specific and can be recorded at any chosen frequency, including high frequencies.
通过瞬态诱发耳声发射（TEOAEs）和畸变产物耳声发射（DPOAEs），了解糖尿病患者（IDDM）耳蜗外毛细胞（OHCs）可能存在的亚临床损伤情况。
对47例听力正常的IDDM患者以及年龄和性别匹配的非糖尿病受试者记录TEOAEs和DPOAEs。通过腓总神经和腓肠神经的神经传导速度（NCV）诊断周围神经病变。
在15例糖尿病患者中发现亚临床周围神经病变。与对照组受试者（11±3.1dB）相比，NCV降低的糖尿病患者的平均TEOAEs幅度显著降低（7.6±3.2dB；谢费检验：P = 0.03），而无神经病变的患者（9.5±4.3dB）则未出现这种情况。神经病变患者在1306至5200Hz的中高频区域DPOAE幅度平均值也降低（P < 0.05），而在最低频率幅度方面未发现差异。与对照组相比，在3284、4126和5200Hz的较高频率区域，非神经病变患者也发现DPOAEs有频率选择性降低（P < 0.05）。糖尿病病程、糖化血红蛋白（HbA1c）值、TEOAEs和DPOAEs之间未发现相关性。
我们的结果表明，IDDM患者表现出OHCs微机械特性的早期异常。在无亚临床周围神经病变的IDDM患者中，损伤仅限于较高频率，且只能通过DPOAEs检测到，而在有神经病变的IDDM患者中，损伤还涉及中频范围，可通过TEOAEs和DPOAEs检测到。因此，DPOAEs似乎能够检测出无周围神经病变的IDDM患者最早出现的耳蜗选择性频率功能障碍。DPOAEs似乎比TEOAEs具有更大的临床意义；前者似乎具有频率特异性，并且可以在任何选定的频率（包括高频）记录。
