Jedrzejczak W Wiktor, Lorens Artur, Piotrowska Anna, Kochanek Krzysztof, Skarzynski Henryk
Institute of Physiology and Pathology of Hearing, ul. Zgrupowania AK Kampinos 1, 01-943 Warszawa, Poland.
J Acoust Soc Am. 2009 May;125(5):3158-65. doi: 10.1121/1.3097464.
The aim of this research is to extend previous studies of the time-frequency features of otoacoustic emissions (OAEs) using information about the properties of the signals at low frequencies. Responses to 0.5 kHz tone bursts were compared to OAEs that were evoked by click stimuli and by 1, 2, and 4 kHz tone burst stimuli. The OAEs were measured using 20 and 30 ms intervals between stimuli. The analysis revealed no differences in the time-frequency properties of 1, 2, and 4 kHz bursts measured using these two different acquisition windows. However, at 0.5 kHz the latency of the response was affected significantly if a shorter time window was used. This was caused by the fact that the response reached a maximum after an average time of 15.4 ms, and lasted a few milliseconds longer. Therefore, for this particular stimulus, the use of a 30 ms time window seems more appropriate. In addition, as an example of the possible application of low-frequency OAEs, signals were measured in patients suffering from partial deafness, characterized by steep audiograms with normal thresholds up to 0.5 kHz and almost total deafness above this frequency. Although no response to clicks was observed in these subjects, the use of 0.5 kHz tone bursts did produce OAEs.
本研究的目的是利用低频信号特性的信息，扩展以往关于耳声发射（OAEs）时频特征的研究。将对0.5kHz短音刺激的反应与由短声刺激以及1kHz、2kHz和4kHz短音刺激诱发的耳声发射进行比较。耳声发射采用刺激间隔为20ms和30ms进行测量。分析表明，使用这两种不同采集窗口测量的1kHz、2kHz和4kHz短音的时频特性没有差异。然而，在0.5kHz时，如果使用较短的时间窗口，反应潜伏期会受到显著影响。这是因为反应在平均15.4ms后达到最大值，并持续几毫秒更长时间。因此，对于这种特定的刺激，使用30ms的时间窗口似乎更合适。此外，作为低频耳声发射可能应用的一个例子，对部分耳聋患者的信号进行了测量，这些患者的听力图特征是在0.5kHz以下阈值正常，在此频率以上几乎完全耳聋。尽管在这些受试者中未观察到对短声的反应，但使用0.5kHz短音刺激确实产生了耳声发射。
