声诱发反应的时变滤波处理

由听觉电生理与电子计算机技术的结合而诞生的电反应测听术,是听力学近十余年的一个重要发展,目前在耳科临床及生理学研究中已得到了广泛的应用。此类方法最大的缺点是速度慢:通常需要百次甚至千次的重复采样和叠加,才能得到一个反应的结果。对叠加效率的提高,不同作者提出了不同的方案,其中有所谓选择性叠加,互相关叠加,计权叠加,潜伏期校准叠加等等,而时变滤波(Time varying filtering)叠加则是较值得探索的技术之一1—3] 通用的平均叠加仪器或设备都有按诱发电位类型而异的固定通带滤波选择,以期得到降低噪声、使信号清晰的效果。此种…

TIME-VARYING FILTERING PROCESS OF SOUND-EVOKED RESPONSES

Different evoked potentials from the auditory system in response to acoustic stimulation were recorded in guinea pigs, monkeys and human subjects.The evoked responses were processed by a computer with the application of the time-varying filtering(TVF) technique which in essence is a time-varying output weighting of the signal after passing through a set of band-Pass filters in correspondence to the time-vary-lug signal/noise ratio of each response.Comparison revealed that the brain stem responses, the cochlear action potentials, the primary responses of the auditory cortex,the periaural responses as well as the slow cortical responses in both animals and hvmans, the response waveform is much clearer in results of the TVF p prdoessing than in those of the ordinary averaging with the TVF processing, the background noise may be markedly suppressed in some cases even to a flat line. The TVF technique hence may serve as a useful means in evoked response recording and its application seems especially efficient in response threshold determination.