Institute of Sound and Vibration Research, University of Southampton, UK.
Int J Audiol. 2010 Mar;49(3):238-46. doi: 10.3109/14992020903280146.
Due to individual characteristics such as head size, earmould type, and earmould venting, the directional benefit that an individual will obtain from a hearing aid cannot be predicted from average data. It is therefore desirable to measure real ear directional benefit. This paper demonstrates a method to measure real ear hearing aid directivity based on a general approach to measure the broadband output signal-to-noise ratio of a hearing aid. Errors arising from non-linearity were tested in simulation and found to be low for typical hearing aid compression ratios. Next, the efficacy of the method to estimate directional benefit was demonstrated on KEMAR. Finally the variability of directional benefit was explored in real-ears. Significant differences in signal-to-noise ratio between directional and omnidirectional microphone settings were demonstrated at most azimuths. Articulation-Index-weighted directional benefit varied by more than 7 dB across ears at some azimuths. Such individual variation in directional benefit has implications when fitting hearing aids: it should not be assumed that all users will receive similar directional benefit from the same hearing aid.
由于头型、耳模类型和耳模通气孔等个体特征，个体从助听器中获得的方向性益处不能从平均数据中预测。因此，测量实际耳助听器方向性益处是理想的。本文展示了一种基于测量助听器宽带输出信噪比的通用方法来测量实际耳助听器方向性的方法。在仿真中测试了由非线性引起的误差，发现对于典型的助听器压缩比，误差很小。接下来，在 KEMAR 上演示了该方法估计方向性益处的效果。最后，在实际耳朵中探索了方向性益处的可变性。在大多数方位上，方向性和全向麦克风设置之间的信噪比存在显著差异。在一些方位上，加权定向增益的清晰度指数在耳朵之间变化超过 7 dB。当适配助听器时，这种方向性益处的个体差异具有重要意义：不应假设所有用户都会从同一助听器中获得类似的方向性益处。
