Development of Automatic Objective Audiometry Device

通过相位相干以特定频率检测睡眠儿童的80 hz振幅调制响应（80 hz AMFR），可以评估听力阈值。但是，这种方法比较耗时。本项目的目的是开发一种使用多重刺激技术和自动阈值检测技术的客观测听装置，该装置仅通过AMFR阈值即可获得听力图。利用个人计算机（NEC PC9821Xa7e）和编程软件（LabVIEW）产生由多个载波频率和多个同时刺激的调制频率组成的混合正弦调幅音。当混合正弦调幅音调制频率之差小于10 Hz时，采用相位相干作为阈值自动检测的分析方法，同时清晰地检测到两种响应。然而，使用相位相干和幅度平方的分析技术在检测响应时并不节省时间。因此，我们开发了一种新的阈值检测分析方法，以节省检测时间。同时记录头皮记录电位和调制波形。调制波形上同相位（90度）连续10个点作为触发器。每个触发器得到10个平均波形，由512个头皮记录电位点组成，并进行相位相干分析。与Fridman的传统分析方法相比，采用该分析技术可将检测时间缩短30%左右。利用该技术，研究了掩模频率和掩模强度对80 hz AMFR阈值的影响。结果表明，音暴对80hz AMFR的掩蔽效应和80hz AMFR的频率特异性足够高。应用该技术的自动客观测听仪目前已在临床上用于校正多重刺激技术的频率特异性和有用性的估计数据。少

Hearing threshold can be evaluated by 80-Hz amplitude-modulation following response (80-Hz AMFR) detected by phase coherence in a frequency specific manner in sleeping children. However, this method is time consuming. The aim of this project was to develop a objective audiometry device using multiple stimulation technique and automatic threshold detection techniques, by which audiogram can be obtained only by AMFR thresholds.Mixed sinusoidally amplitude modulated tone consisted of several carrier frequencies and modulation frequencies for multiple simultaneous stimuli was produced using personal computer (NEC PC9821Xa7e) and programming software (LabVIEW). When the difference of modulation frequencies of mixed sinusoidally amplitude modulated tone was less than 10 Hz, two responses were detected clearly and simultaneously using phase coherence as a analyzing method for the automatic detection of threshold. However, the analyzing technique using phase coherence and magnitude-squared coh … More erence was not so time saving in the detection of responses. Therefore, we developed a new analyzing method for the detection of threshold for examination time saving. Scalp-recorded potential and modulation waveform were recorded simultaneously. Succeeding 10 points in the same phase (90 deg) on modulation waveform were used as triggers. Ten averaging waveforms consisted of 512 points of scalp-recorded potentials were obtained using each trigger and were analyzed by phase coherence.Using this analyzing technique, examination time was shortened to about 30% comparing with conventional method developed by Fridman. Using this technique, the effect of masker frequency and intensity produced by a tone burst on AMER threshold was investigated for the estimation of frequency specificity of 80-Hz AMFR.The results suggested masking effect by tone burst on 80-Hz AMFR and frequency specificity of 80-Hz AMFR to be high enough.Automatic objective audiometry device using this technique is now using clinically to correct the data for the estimation of frequency specificity and usefulness of multiple stimulation technique. Less