中枢掩蔽与耳声发射对侧抑制相关性研究

目的：探讨中枢掩蔽与耳发射对侧抑制的相关性。方法：通过对一组耳科正常青年人及4例蜗后聋患者同时进行相同条件下中枢掩蔽及耳声发射对侧抑制的测试，观察中枢掩蔽与耳声发射对侧抑制在同一实验对象的表现。结果：在正常人组中，当对侧掩蔽声小于60 d BHL时，中枢掩蔽效应及耳声发射的对侧抑制均随对侧掩蔽声增加而增大，掩蔽强度大于60 d BHL时，则出现过度掩蔽。耳声发射记录过程中，本底噪声明显升高。当对侧掩蔽声固定为60 d BHL时，中频1.0、2.0kHz中枢掩蔽效应及耳声发射对侧抑制明显高于低频及高频，2.0kHz处最为明显；在蜗后聋组中，健耳或听力损伤较轻耳，中枢掩蔽及耳声发射对侧抑制接近正常人耳，而患者或听力损失较重耳，中枢掩蔽效应为负值或零，对侧抑制表现为反抑制或不抑制。结论：中枢掩蔽与对侧抑制存在相同的发生机理，表现出相同的频率特异性及强度特异性，无论在正常人耳还是病变耳，均表现出高度的相关性。

Investigation of Identity Between Central Masking Effect and Contralateral Suppression of OAEs

Objective To probe into the correlation between central masking effect and contralateral suppression of OAEs.Methods A group of normal young volunteers (20 cases, 40 ears, 10 men and 10 women) and 4 cases with sensory hearing loss were tested to observe the central masking effect (CME) and the contralateral suppression of OAEs (CS of OAE) at the same time under the same conditions int order to investigate the appearance of CME and CS of OAEs in the same subjects.Results In the normal group, when the masker was lower than 60 dB HL, the CME and the CS of OAEs become higher as the masker was tuned higher,when the masker was higher than 60 dB HL,came the overmasking and the OAEs noise floor became higher. When the subjects were given a steady contralateral masker of 60 dB HL, the CME and the CS of OAEs appeared apparetly at 1.0 kHz and 2.0 kHz, especially at 2.0 kHz. In the group of sensory hearing loss, the healthy ears of the ears with slight hearing loss, the CME and the CS of OAEs were close to the normal, but at the other ear of the same subjects, the CME and the CS of OAEs were negative of zero. Conclusion The CME and the CS of OAEs owned the same mechanism, appeared the same frequency-selective properities and sound level-selective properities. Not only at the normal, but also at sensory hearing loss cases, the CME and the CS of OAEs appeared high correlated.