Beattie R C, Boyd R L
Audiology. 1985;24(6):406-19. doi: 10.3109/00206098509078360.
Early/middle auditory-evoked potentials were recorded on 10 normal-hearing adults using 500-, 1 000, and 2 000-Hz tone bursts having 4-ms rise-fall and 1-ms plateau times. The stimuli were presented in quiet, white noise and notched noise at 50, 40, 30, 20 and 10 dB nHL. The noises were selected to improve frequency specificity by masking those regions of the cochlea that do not correspond to the test stimulus. The recording-amplifier system had a bandpass of 55-1 500 Hz; electric activity was measured during the 25-ms post-stimulus interval. The three waves observed during this time interval (P10, N15, and P20) were labeled to reflect polarity and latency. The results revealed no differences among stimulus conditions (quiet, white noise, notched noise) in the number of identifiable responses for any wave at any intensity. Moreover, no P10, N15 or P20 latency differences were observed among conditions at 40 dB nHL and below. When 500-Hz tone bursts were presented at 50 dB nHL, however, significantly shorter response latencies were observed in quiet than when the tone bursts were mixed with white noise or notched noise. It was concluded that frequency specificity can be improved when tone bursts are mixed with notched noise or white noise. White noise is preferred, however, because it can be implemented with less complex instrumentation and calibration than notched noise.
对10名听力正常的成年人记录早期/中期听觉诱发电位，使用上升-下降时间为4毫秒、平台期为1毫秒的500赫兹、1000赫兹和2000赫兹的短纯音。刺激声分别在安静环境、白噪声以及50、40、30、20和10分贝正常听力级（dB nHL）的窄带噪声中呈现。选择这些噪声是为了通过掩蔽耳蜗中与测试刺激不对应的区域来提高频率特异性。记录放大器系统的带通为55 - 1500赫兹；在刺激后25毫秒的时间间隔内测量电活动。在此时间间隔内观察到的三个波（P10、N15和P20）根据极性和潜伏期进行标记。结果显示，在任何强度下，任何波的可识别反应数量在不同刺激条件（安静、白噪声、窄带噪声）之间均无差异。此外，在40 dB nHL及以下的条件下，未观察到P10、N15或P20潜伏期的差异。然而，当以50 dB nHL呈现500赫兹短纯音时，与短纯音与白噪声或窄带噪声混合时相比，在安静环境中观察到的反应潜伏期明显更短。得出的结论是，当短纯音与窄带噪声或白噪声混合时，频率特异性可以提高。然而，白噪声更受青睐，因为与窄带噪声相比，它可以用更简单的仪器和校准来实现。
