成对短声不同间隔对单、双耳听觉脑干反应的影响——衍生听觉脑干反应方法的应用

INFLUENCE OF DIFFERENT INTERVALS OF MONAURAL AND BINAURAL PAIRED-CLICK STIMULI ON AUDITORY BRAIN STEM RESPONSE: THE USE OF DERIVED ABR

采用具有不同间隔(0～32ms)的65dB nHL(正常听力水平)的成对短声刺激,记录20名正常人的单侧耳和两耳交替刺激的听觉脑干反应(ABR)。用计算机从成对短声反应中减去单一短声反应以提取衍生ABR。结果表明,单、双耳的衍生ABR V波振幅在成对短声间隔为0.2～1.5ms时,受到明显影响。单耳的减小54％～65％(P<0.01),两耳的减少46％～53％(P<0.01),但单、双耳的衍生ABR I波振幅未显示显著差异(P>0.05)。该结果说明,高位脑干通路在成对短声间隔为0.2～1.5ms时,不但对同侧耳的第2个短声反应能力降低,而且对来自对侧耳的第2个短声也如此。从而推断,在两耳交替刺激的耳间短声间隔小于2ms范围时,在下丘部位可能存在两耳交互作用。结果还提示,临床检查ABR时,采用的短声刺激间隔至少不应小于30ms。

Auditory brain stem responses (ABR) to 65-dB nHL click and paired click were recorded in 20 adults with normal hearing. Paired-click interval ranged from 0 to 32 ms. Derived ABR were obtained by subtraction of single-click from paired-click responses with computer. The results showed that the amplitudes of wave-V of monaural and binaural derived ABR were apparently affected at paired-click interval ranged from 0.2 to 1.5 ms. The amplitude of wave-V of monaural derived ABR decreased by 54%-65% (P<0.01) and that of binaural derived ABR decreased by 46%-53% (P<0.01). But the amplitudes of wave-I of the derived ABR were not significantly affected. The results suggested that the high brain stem pathway could not fully respond to the second click of the paired-click with an interval ranged from 0.2 to 1.5 ms or to the second click from the contralateral ear at the same interval. In consequence, it can be inferred that a binaural interaction takes place in the region around the inferior colliculus when the interaural interval of paired-click is shorter than 2ms. The results also suggest that the stimulus interval should not be shorter than 30ms in examination of ABR.