Harris F P, Probst R, Xu L
Department of Otorhinolaryngology, Kantonsspital Basel, Switzerland.
Hear Res. 1992 Dec;64(1):133-41. doi: 10.1016/0378-5955(92)90175-m.
Suppression of the 2f1-f2 distortion-product otoacoustic emission (DPOAE), stimulated with primaries, f1 and f2, in the frequency regions of 1, 2, and 4 kHz was measured in one ear of 14 human subjects with normal hearing. Suppression rate functions were generated with a suppressor at either 1, 2, or 4 kHz increasing in level from 30 to 76 dB SPL for the corresponding f1 and f2 combinations. Stimulus levels for DPOAEs were L1 = 70 dB SPL and L2 adjusted to produce the highest amplitude DPOAE for each ear (range, 0 to 6 dB below L1). Results indicated that DPOAEs were reduced 3 dB in amplitude for a mean suppressor level of 61 dB SPL. Maximum amplitude reduction occurred at a mean suppressor level of 69 dB SPL. These levels varied little for the three stimulus frequency regions. Mean slopes of the rate functions decreased as stimulus frequency region increased. Suppression tuning curves (STCs) were generated in the same three frequency regions and with L1 at either 70 or 55 dB SPL and L2 adjusted individually for each ear. The tips of the STCs were at frequencies associated with f1 and f2. The tip regions of the STCs for the 4-kHz stimulus condition were more complex in that they contained more multiple minima than did those for the 1- and 2-kHz regions. Results confirm that optimal suppression of the 2f1-f2 DPOAE occurs for frequencies in the vicinity of f1 and f2 rather than at 2f1-f2.
在14名听力正常的人类受试者的一只耳朵中，测量了在1、2和4kHz频率区域用初级频率f1和f2刺激时2f1 - f2畸变产物耳声发射（DPOAE）的抑制情况。对于相应的f1和f2组合，当抑制器在1、2或4kHz，声压级从30dB SPL增加到76dB SPL时，生成抑制率函数。DPOAE的刺激声压级为L1 = 70dB SPL，L2进行调整以使每只耳朵的DPOAE振幅最高（范围为比L1低0至6dB）。结果表明，对于平均抑制器声压级为61dB SPL时，DPOAE的振幅降低了3dB。最大振幅降低发生在平均抑制器声压级为69dB SPL时。这三个刺激频率区域的这些水平变化很小。随着刺激频率区域增加，率函数的平均斜率降低。在相同的三个频率区域中生成抑制调谐曲线（STC），L1为70dB SPL或55dB SPL，L2针对每只耳朵单独调整。STC的尖端位于与f1和f2相关的频率处。4kHz刺激条件下STC的尖端区域更复杂，因为它们比1kHz和2kHz区域包含更多的多个极小值。结果证实，2f1 - f2 DPOAE的最佳抑制发生在f1和f2附近的频率，而不是在2f1 - f2处。
