自发性耳声发射随时间变化的稳定性分析

摘要

目的 评估自发性耳声发射(spontaneous otoacoustic emissions,SOAE)信号随时间变化的稳定性.方法 通过对1名听力正常的26岁女性为期18周的SOAE检测,测试间隔为1周,观察其SOAE信号的重复出现率,SOAE的频率及强度随时间的变化情况.结果 ①18周(18次)的测试中共记录到256个SOAE信号 (左耳160个,右耳96个),依据SOAE信号重复出现率将其分为3类:A.稳定信号,占85.2%(右耳83.1%,左耳88.5%);B.欠稳定信号(仅在右耳记录到,占右耳SOAE信号数的7.5%);C.偶发信号,占10.1%(右耳9.4%,左耳11.5%).②稳定SOAE信号的重复出现率为93.2%(右耳92.4%,左耳94.4%),其中22%的SOAE信号出现了信号内的频率变异,而且89.6%频率变异只是增减了一个最小刻度(12.3 Hz).③右耳SOAE强度变异系数在10.5%～25.6%之间,左耳在17.0%～41.2%之间.右耳SOAE强度的极差为15.3 dB,左耳为16.2 dB.④偶发SOAE的出现率最高为22%,69.2%(18/26)位于2 kHz以下频率区,30.8%(8/26)多位于2 kHz以上频率区.偶发SOAE信号的平均强度为(-20.30±7.13) dB,在1 kHz以下的平均强度为(-12.48±2.60)dB,显著高于1kHz以上区的平均强度(-26.03±1.69 dB),差异有统计学意义(t=15.10;P＜0.05).结论 SOAE信号峰具有很高的重复出现率,出现后的频率具有很高的稳定性,但是强度波动较大.%Objective The aims of this study were to investigate the long-term variations in amplitude and frequency of spontaneous otoacoustic emissions(SOAE). Methods SOAE were measured in a 26 years old woman with normal hearing. Eighteen repeated measurements were recorded over time periods of eighteen weeks. Interval between two tests was one week. Variations in amplitude and frequency of SOAE were assessed. Results ① Totally 256 SOAE signals were recorded in both ears during the eighteen measurements, 160 SOAE in right ear and 96 SOAE in left ear. Basing on the probability of repetitive appearance of SOAE in eighteen repeated measurement, SOAE were classified into three types: stable SOAE, less stable SOAE and unstable SOAE. The probability of SOAE appearance in total measurements were higher than 75％ were defined as stable SOAE. The probability of SOAE appearance between 25％ and 75％ were defined as less stable SOAE; The probability of SOAE appearance less than 25％ were unstable SOAE.Eighty-five point two percent SOAE(84.7％ in right ear, 85.9％ in left ear) were stable signal in total 256 SOAE signals, less stable SOAE was only recorded in right ears, accounting for 7.5％ in right ear, 10.1％ SOAE (9.4％ in right ear, 11.5％ in left ear) were unstable SOAE. ② The probability of repetitive appearance of stable SOAE were 93.2％ (92.4％ ％ in right ear, 94.4％ in left ear).Only to have 22％ of the stable SOAE signal appeared the frequency variation, those frequency variations were still within the original signal. Eighty-nine point six percent of it was only appeared that the peak frequency of SOAE signal declined or raised one minimum scale of ILO 9 6 ( 12.3 Hz ) . ③ Amplitude of the stable SOAE shows wide fluctuations. Coefficient of variability of the stable SOAE amplitude fluctuated between 10.5％ and 25.6％ in right ear, and between 17.0％ and 41.2％ in left ear. The range of maximum fluctuation of SOAE level was 15.3 dB in right ear and 16.2 dB in left ear over a time interval of one week. ④ The maximum probability of repetitive appearance of unstable SOAE was only 22％. Sixty-nine point two percent (18/26) of unstable SOAE occurred in lower than 2 kHz, only 30.8％ (8/26) of unstable SOAE occurred in higher than 2 kHz. The mean of unstable SOAE level was( - 20.30 ± 7.13 ) dB. The mean level for unstable SOAE occurred in lower than 1 kHz was( -12.48 ±2.60) dB, which was significantly higher than the mean level for unstable SOAE occurred in higher than 1 kHz( - 26.03 ± 1.69dB) ( t = 15.10, P ＜ 0.05 ). Conclusion SOAE shows a high probability of repetitive appearance and high stability in frequency. However, amplitude of the SOAE shows wide fluctuations.