Portmann M, Harrison R V, Negrevergne M, Dauman R, Aran J M
Acta Otolaryngol. 1983 May-Jun;95(5-6):657-63. doi: 10.3109/00016488309139459.
One of the basic functions of the cochlea is to separate out the frequency components which are present in complex sounds. This frequency selectivity can be measured objectively in the clinic from the compound action potential (AP) during transtympanic electrocochleography, using a two-tone masking paradigm. An AP is evoked by a test tone near to threshold, and a measure is made of the frequency bandwidth over which this AP can be suppressed by a continuous pure tone masker. In normal-hearing subjects, this frequency range is 0.17-0.39 octaves (test tone pip at 4 or 8 kHz). In patients with cochlear deafness, this bandwidth is greatly enlarged, ranging from 0.42-2.2 octaves. Some observations suggest that a deterioration in frequency selectivity can occur before any important threshold elevation. The early detection of this could be a warning sign of potential cochlear susceptibility. In the clinic the measure is already of use: a deterioration is a positive indication of cochlear involvement in a hearing loss.
耳蜗的基本功能之一是分离复杂声音中存在的频率成分。这种频率选择性可以在临床上通过经鼓膜电耳蜗图期间的复合动作电位（AP），使用双音掩蔽范式进行客观测量。接近阈值的测试音诱发AP，并测量该AP可被连续纯音掩蔽器抑制的频率带宽。在听力正常的受试者中，该频率范围为0.17 - 0.39倍频程（测试音短声在4或8kHz）。在耳蜗性耳聋患者中，该带宽大大扩大，范围为0.42 - 2.2倍频程。一些观察结果表明，在任何重要的阈值升高之前，频率选择性可能会恶化。对此的早期检测可能是潜在耳蜗易感性的一个警示信号。在临床上，该测量方法已经在使用：恶化是耳蜗参与听力损失的一个阳性指标。
