Objective audiometry using positive slow wave of auditory brainstem response

本研究从1986年至1987年对ABR顶点正性慢波（PSW）的应用潜力进行了探讨，为评价PSW的频率特异性，进行了两个实验。1)一个音对音同时掩蔽范式被用来确定调谐曲线在大鼠。调谐曲线被构建以定义导致探针引起的PSW振幅减少50%的掩蔽强度。Q_<10>值分布在1.0和1.6之间。调谐曲线的最大掩蔽频率不一定等于没有2kHz的探头的频率。2)同样的范例也用于人类受试者。Q<10>值随频率的增加而逐渐增大。它们分布在1.0和5.3之间。Tueing曲线的最大掩蔽频率不一定等于探测频率。这些结果表明，短纯音刺激可以在不同的频率下评估特定的听觉功能，并且它们在刺激频率附近具有更宽的耳蜗区频率分布。1)从长持续时间和相同升降时间的短纯音刺激诱发的波中减去短纯音诱发的波。其结果表明，在人类受试者记录的PSW也延长了短纯音的持续时间增加。2)采用非头侧参考电极法记录头皮PSW。结果表明，PSW在C_z处振幅最大。A_1、A_2为主动电极，正性慢波振幅高于标准耳尖-耳垂差，在临床应用中存在一定的困难。然而，该项目的结果表明，它有潜力作为客观测听的工具。

Through the present ressearch project from 1986 to 1987, the potential of application of vertex-positive slow wave ( PSW ) of the ABR was investigated.In order to evaluate frequency specificity of the PSW, two experiments were performed. 1) A tone on tone simultaneous masking paradigm was used to determine tuning curves in rats. Tuning curves were constructed to define masker intensity that resulted in a 50% reduction in probe elicited PSW amplitude. Q_<10> values were distributed between 1.0 and 1.6. Maximum masker frequencies of the tuning curves were not necessarily equal to the frequency of probe without 2-kHz. 2) The same paradigm was used in human subjects. Q_<10> values were gradually increased with the increase in frequency. They were distributed between 1.0 and 5.3. Maximum masker frequencies of the tueing curves were not necessarily equal to the frequency of probe. These results indicate that the short tone burst stimuli may enable to assess certain auditory function at different frequencies, and they have wider frequencies' spread of the cochlear area around stimulus frequencies.In order to get stabilized PSW in human subjects, two experiments were performed. 1) The wave evoked by short tone burst was subtracted from the the wave evoked by the stimulus which consists long duration and same rise-fall time as the short tone burst. Its results showed that the PSW recorded in human subjects were also elongated as the duration of a tone burst was increased. 2) The PSW were recorded from the scalp using non-cephalic reference electrode method. The study led us to the conclusion that the PSW were of maximal amplitude at the resion of C_z. A_1 and A_2 are active electrode, thus, amplitude of positive slow wave is higher than that from standard vertex-earlobe deviation.There are some difficult problems in the clinical application of the positive slow weve of ABR. However, the results of the project indicate that it has potential as a tool for objective audiometry.