Frequency compression on speech recognition in elderly people with possible cochlear dead regions

PURPOSE: to evaluate and compare the performance of elderly people with and without cochlear dead regions in speech recognition tests, in silence and in noise, using hearing aids with and without the activation of the nonlinear frequency compression algorithm. METHODS: 38 elderly people with mild to moderate hearing loss and descending configuration, distributed based on the results of the white noise masking technique, in: Group A - 24 elderly people without evidence of cochlear dead regions; Group B - 14 elderly people with evidence of cochlear dead regions. The Lists of Sentences in Portuguese test was applied, seeking the Percentage Index of Sentence Recognition in silence and in noise. The measurements were obtained using the hearing aids without and with nonlinear frequency compression. RESULTS: both Group A and Group B showed statistically significant improvement in silence with the hearing aids with the algorithm; in noise no group presented significant difference without and with frequency compression. Comparing the groups, there was no significant difference in silence without and with frequency compression. In noise without the algorithm there was significant difference, Group B being the better of the two. In noise without frequency compression there was no significant difference. CONCLUSION: in silence, both groups presented significant improvement in performance using hearing aids with frequency compression. In noise, there was no difference between the results without or with frequency compression. Comparing the groups, the measurement obtained in noise with hearing aids without the algorithm was the only one that presented a significant difference, in which the group with cochlear dead regions presented a better performance.

研究目的：评估并比较伴与不伴耳蜗死区（cochlear dead regions）的老年受试者，在安静与噪声环境下，分别使用启用/未启用非线性频率压缩（nonlinear frequency compression）算法的助听器时的言语识别表现。研究方法：招募38名存在轻度至中度听力损失且听力图呈下降型构型的老年受试者，依据白噪声掩蔽技术（white noise masking technique）的检测结果分为两组：A组——24名未检出耳蜗死区的老年受试者；B组——14名检出耳蜗死区的老年受试者。采用葡萄牙语语句表测试（Lists of Sentences in Portuguese test），采集安静与噪声环境下的语句识别百分比指数（Percentage Index of Sentence Recognition）。所有测量均分别在助听器未启用与启用非线性频率压缩算法的条件下完成。研究结果：A组与B组在使用搭载该算法的助听器时，安静环境下的言语识别表现均出现统计学意义上的显著提升；噪声环境下，无论是否启用频率压缩算法，两组自身的测试结果均未出现显著差异。组间比较显示，无论助听器是否启用频率压缩算法，安静环境下两组的测试结果均无显著差异。未启用算法的噪声环境测试中，两组间存在显著差异，B组表现更优；而启用频率压缩算法的噪声环境测试中，组间无显著差异。研究结论：安静环境下，两组受试者使用搭载非线性频率压缩算法的助听器时，言语识别表现均出现显著提升。噪声环境下，无论是否启用该算法，两组的测试结果均无显著差异。组间比较显示，仅在未启用算法的噪声环境测试中，两组间存在显著差异，其中伴耳蜗死区的B组表现更优。