【作者】 张新安；

【导师】 刘技辉；

【作者基本信息】 中国医科大学 ， 法医学， 2007， 硕士

【摘要】 中、短潜伏期听觉诱发电位及其法医学应用价值的研究前言在临床法医学鉴定中，对听力(Auditory)损害等级的划分标准主要以言语频率(500Hz、1000Hz、2000Hz)听阈均值的分贝数为标准。听觉脑干诱发电位(auditory brainstem potentials，ABR)是目前听觉诱发电位(auditory evoked potentials，AEP)检查中应用最广、技术也最为成熟的客观测听方法。但是由于短声反映的主要是2000Hz以上的高频听阈的情况，不能很好反映中低频率的听阈。因此，客观测听方法的研究是临床法医学的一个重要课题。目前国内有关瞬态中潜伏期听觉诱发电位(middle latency response，MLR)在听功能评定测试中应用的研究较少，在法医学上应用短纯音诱发的瞬态MLR客观评定听功能的研究尚无相关报道。本研究对59名(其中听力正常组40名80正常耳，耳聋组19名28只聋耳)受试者依次测试纯音听阈、短纯音诱发的瞬态MLR及40Hz AERP和短声诱发的ABR，对它们的频率特异性、低中高频声音刺激的敏感性以及测试中的影响因素等进行分析和评价，旨在达到评价中、短潜伏期听觉诱发电位的法医学应用价值之目的。受试对象与方法受试对象：听力受试者59名，其中正常听力受试组40名80耳均为在校大学生，其听力正常的判定标准为各频率的纯音气导听阈均＜25dBHL。耳聋组19名28只聋耳。耳聋的确认：自诉耳聋，ABR检查结果异常，通过纯音气导听阈测听确定其不同频率听力状况，并通过同频音掩蔽试验验证。试验方法：受试者躺在隔音室检查床上，首先依次测试受试者1000Hz、500Hz、2000Hz和4000Hz的纯音气导听阈，然后再测试短纯音诱发的瞬态MLR和40Hz AERP反应阈、短声诱发的ABR反应阈。纯音听阈测试采用FONMXFA—12型纯音听力计，频率范围：125Hz～8000Hz，最小输出：—10dBHL，最大输出：110dBHL。测试瞬态MLR、40Hz AERP、ABR反应阈时，采用Nicolet Compact Four多功能电生理记录仪做为描记系统，由TDH—39P型耳机给声，采用银盘电极记录各诱发电位，记录电极置于头顶正中，参考电极位于同侧乳突，前额正中发际下1cm处置接地电极，电极阻抗＜5kΩ，极间电阻相差＜3kΩ。描记各反应波时，正常听力组由80dB，耳聋组由110dB开始，然后以每10dB nHL为一档递减，直至反应波形消失。测试结果用X—Y记录仪记录。结果1、正常听力组的短纯音诱发瞬态MLR测试，在四个测试频率上，均可诱发出三个正相波、三个负相波，分别为NO、PO、Na、Pa、Nb、Pb。2、不同频率瞬态MLR各波的潜伏期不同，随着刺激声频率的升高，各波的潜伏期缩短。睡眠对瞬态MLR和40Hz AERP测试有一定的影响。3、在500Hz、1000Hz、2000Hz和4000Hz四个频率上，正常听力组主观纯音听阈的均值和标准分别为14.13±4.48dB、9.31±4.39dB、6.44±5.11dB、7.56±7.20dB，瞬态MLR反应阈的均值和标准差分别为20.31±4.99dB、15.81±4.61dB、18.06±6.33dB、19.63±7.24dB、40Hz AERP反应阈均值和标准差分别为19.50±5.00dB、15.68±5.08dB、15.56±6.00dB、19.68±8.28dB，ABR反应阈的均值和标准差为22.31±5.03dB。4、在500Hz、1000Hz、2000Hz和4000Hz四个频率上，正常听力组的瞬态MLR反应阈与纯音听阈之差的均值和标准差分别为6.19±2.14dB、6.50±2.57dB、11.63±9.80dB、12.06±3.25dB、40Hz AERP反应阈与纯音听阈之差的均值和标准差分别为5.38±2.61dB、6.38±3.08dB、9.13±3.35dB、12.13±3.35dB。500Hz、1000Hz、2000Hz和4000Hz四个频率上，瞬态MLR反应阈与主观听阈的回归方程分别是Y=0.81x-2.36、Y=0.79x-3.17、Y=0.63x-4.99、Y=0.90x-10.11；40Hz AERP反应阈与主观听阈的回归方程分别是Y=0.77x-0.80、Y=0.68x-1.37、Y=0.71x-4.54、Y=0.80x-8.21。5、在500Hz、1000Hz、2000Hz、4000Hz四个频率上，耳聋组瞬态MLR反应阈与纯音听阈之差的均值和标准差分别为6.79±2.43 dB、6.60±2.74 dB、11.07±3.15 dB、11.78±2.43 dB；40Hz AERP反应阈与纯音听阈之差的均值和标准差分别为5.00±2.36 dB、5.89±4.52 dB、8.75±3.23 dB、12.68±3.96 dB。对耳聋组与正常听力组的瞬态MLR、40Hz AERP反应阈与纯音听阈的差值进行总体均数t检验，二者均无显著性差异(P＞0.05)。高频听力损失组(高频听力损失为主)和低频听力损失组(低频听力损失为主)的纯音听力曲线图中，ABR反应阈与纯音主观听阈在低频声音的差值不同。结论1、用短纯音可以诱发出稳定的瞬态MLR和40Hz AERP，瞬态MLR主要由三个正相波，三个负相波组成，分别为N0、P0、Na、Pa、Nb、Pb波，潜伏期在7～65ms之间。40Hz AERP为一组正弦融合波。2、ABR对中低频声音不能很好的反应、而对高频声音反应较好，可用于评价高频声音的听阈状况。中潜伏期听觉诱发电位反应阈接近纯音主观听阈，特别40Hz AERP反应阈更接近纯音主观听阈，可用于各个频率尤其是中低频听阈的客观评定。睡眠对瞬态MLR和40Hz AERP反应阈有一定影响，尤其对瞬态MLR影响更大。3、随着刺激声频率的增高，短纯音诱发的瞬态MLR反应的潜伏期缩短。根据同一声强、不同频率瞬态MLR各波潜伏期变化特点，可以推断高频性耳聋或低频性耳聋。4、在法医学鉴定中，应用短纯音诱发瞬态MLR时应注意选择合适的带通滤波、扫描时间、适当的叠加次数及适宜的声音进行刺激，以获得稳定的瞬态MLR波形、用于法医学鉴定听功能客观评定。更多还原

【Abstract】 In clinical forensic medicine expertise, the standard for the degree of the auditory loss by the language frequency for the average value of 0.5kHz, lkHz and 2kHz. The auditory brainstem response (ABR) has been developed as the most widely application for the objective assessment. However, the ABR evoked by clicks has some limitations, as it evaluates hearing sensitivity only at higher frequencies above 2000Hz but can not be sensitive for the thresholds for lower and middle frequencies.These studies for objective method of hearing thresholds were important questions in clinical forensic medicine. At present,in our country, there is little study for transience MLR on hearing thresholds. In the forensic medicine, there were no related study report about transience middle latency response (MLR) evoked by tone brust on hearing thresholds.In this study, the subjects for 59 volunteers,40(80 ears) and 19(28 deaf ears) were included. We tested for the pure tone threshold audiometry(PTA), transience MLR,40Hz auditory evoked response potential evoked by tone trust, then thested auditory brain-stem potentials evoked by click. Comparing and analysising their frequency-specific stimuli, sensitive, and influence factors in the test, the aim is toevaluate their their application value in the forensic medicine.Subjects and methodsThe subjects for 59 volunteers , forty normal hearing undergraduate (80 ears) volunteers at China Medical University and 19 deaf volunteers (28 ears) participated in our experiment. Forty normal hearing undergraduate (80 ears) volunteers had normal hearing sensitivity at all frequencies from 500 to 8000 Hz (＜25dBHL). For the deaf group, the following is the diagnosis standard of the deaf, deaf is from private prosecution, the test of ABR is abnormal, hearing thresholds in all frequencies from 500 to 8000 Hz testd by pure tone threshold audiometry, to affirm them by the the Same Frequency Tone Masking Test.The subjects reclined comfortably on an examination couch in an audiometric room. After pure tone auditory thresholds had been obtained at 1000, 500, 2000 and 4000Hz, 40Hz AERP and transience MLR thresholds to tone burst, ABR by click. Tone pips were determined. The response to tone burst was recorded with a Nicolet Compact Four Electrodiagnostic System. The earphone (TDH-39P) produced tone pips. The electrodes were placed at the vertex (positive input), ipsilateral mastoid (negative input) and forehead (ground). Individual impedances were less than 5kΩand inter-electrode impedance was below 3kΩ. The subjects reclined comfortably on an examination couch in an audiometric room. AEP to tone pips testing was started at 80dB nHL for normal group, 110dBnHL for deaf group. The stimulus level was decreased with 10dBnHL until no AEP waveforms could be detected. The responses were written out on a X-Y plotter at last.Results1. For the normal group, when the transience MLR evoked by tone trust, Three positive waves and three nagative waves were obtained from all the subjects for each frequency, So we called them NO、P0、Na、Pa、Nb、Pb.2. As the frequency of tone pips increases, the latency of each transience MLR waves decreases. The transience MLR and 40 Hz AERP threshold can be influenced by sleep.3. Mean differences and standard deviations for PTA at 500, 1000, 2000 and 4000Hz were 14.13±4.48 dB、9.314±4.39 dB、6.444±5.11 dB、7.56±7.20 dB, respectively. Mean differences and standard deviations for the transience MLR thresholds to trust tone were 20.31±4.99 dB、15.81±4.61 dB、18.06±6.33 dB、19.63±7.24 dB, respectively. Mean differences and standard deviations for 40Hz AERP thresholds to trust tone were 19.50±5.00dB、15.68±5.08 dB、15.56±6.00 dB、19.68±8.28 dB, respectively. Mean differences and standard deviations for ABR is 22.31±5.03 dB. 4. Mean differences and standard deviations between the transience MLR thresholds to trust tone and PTA were 6.19±2.14dB、6.50±2.57 dB、11.63±9.80 dB、12.06±3.25 dB, respectively. Mean differences and standard deviations between 40Hz AERP thresholds to trust tone and PTA were 5.38±2.61 dB、6.384±3.08 dB、9.13±3.35 dB、12.13±3.35 dB、respectively. At 500, 1000, 2000 and 4000Hz, the regression equation between transience MLR thresholds and PTA is Y=0.81x-2.36, Y=0.79x-3.17, Y=0.63x-4.99, Y=0.90x-10.11, respectively, the regression equation between 40Hz AERP thresholds and PTA is Y=0.77x-0.80, Y=0.68x-1.37, Y=0.71x-4.54, Y=0.80x-8.21, respectively.5. Mean differences and standard deviations between MLR thresholds to trust tone were 6.79±2.43dB, 6.60±2.74 dB, 11.07±3.15 dB, 11.78±2.43 dB, respectively. Mean differences and standard deviations between 40Hz AERP thresholds to trust tone were 5.00±2.36 dB, 5.89±4.52 dB, 8.75±3.23 dB, 12.68±3.96 dB, respectively. For the normal and deaf groups,There were no significant deviation for the mean differences of the differences between MLR,40Hz AERP thresholds to tone trust and pure tone thresholds(P＞0.05). For the pure auditory curve chart, there were exceedingly significant deviation at the high frequency losing group and the low frequency losing group.Conclusion1. For the normal group, when the transience MLR evoked by tone trust, three positive waves and three nagative waves were obtained from all the subjects for each frequency. The latency of the component was between 7 and 65 ms, so we called them NO、P0、Na、Pa、Nb、Pb. The transience MLR threshold can be influenced by sleep. 40Hz AERP is composed by some fusion waves.2. ABR can not be sensitive for middle and low frequency, but be very sensitive for high frequency, it can be used to evaluate hearing threshold in high frequency. MLR threshold is near the subject tone threshold, especially 40Hz AERP, so they can be used to evaluate hearing threshold in middle or low frequency. MLR threshold can be influenced by sleep, especially the transience MLR.3. As the frequency of tone pips increases, the latency of each transience MLR waves decreases. By the same intensity of sound, the latency diversify characteristic of different frequency transience MLR, We can inference the deaf low frequency hearing lose or high frequency hearing lose.4. In the forensic medicine expertise, only when suitable bandpass filtering, superposition number of times and eligible tone were selected, can we obtain stabile MLR waves, it can be used for hearing threshold evaluation in forensic medicine expertise.更多还原