A study on the development of a high-performance digital hearing aid and the method of its fitting

在为这项研究定制的便携式数字助听器中安装了补偿响度重新招募的算法，并在日常生活中对其性能进行了评估。对于较低的输入电平，响度补偿函数被设置为线性，从而实现了谱减法以抑制环境或背景噪声。虽然数字助听器的特点是灵活，但试戴往往需要相对较长的时间。因此，还研究了准确有效地估计响度补偿函数的方法。在此基础上，对100多名听障者的响度补偿函数进行了测量，并对其进行了拟合。配戴的数字助听器在日常生活中由受损者进行长期的现场测试。听众对助听器的性能进行了七个类别的评分，包括在安静的情况下听收音机/电视，在安静和嘈杂的环境中几个人之间交谈，在很多人之间交谈，在街上听演讲，评价自己说话的质量等。结果表明，在所有情况下，新型助听器的性能都明显优于传统助听器。

The algorithm compensating for loudness recruitment was installed in portable digital hearing aids that were custom-made for this study, and its performance was evaluated in daily lives. The loudness compensation function was set to be linear for lower input levels, so that spectral subtraction was achieved to suppress environmental or background noise. Though digital hearing aids have the merit of flexibility in their characteristics, it often takes relatively long time for fitting. Thus, methods for estimating accurate loudness-compensation function efficiently were also studied. As the result of the study, it has been shown that the subdivided one-step categorical scaling method is the best method for the present purpose.On the basis of these results, loudness compensation functions were measured for more than one hundred impaired-listeners, and the fitting procedure was carried out with those functions to the impaired. Long-time field tests with the fitted digital hearing aids were conducted by the impaired in their daily lives. The listeners evaluated performance of the hearing aids in a scale of seven categories for some situations such like listening to radio/television in quiet, conversation among a few persons in quiet and in noisy environment, conversation among great numbers of people, listening to speech on the street, appraisal of the quality of self-uttered voice, and so on. The results show that the performance of the new hearing aids are significantly better than those achieved by conventional hearing aids in all the situations.