Effects of Frequency Compression and Frequency Transposition on Fricative and Affricate Perception in Listeners With Normal Hearing and Mild to Moderate Hearing Loss
Effects of Frequency Compression and Frequency Transposition on Fricative and Affricate Perception in Listeners With Normal Hearing and Mild to Moderate Hearing Loss
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DOI：
10.1097/aud.0000000000000040
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发表时间：
2014-09-01
期刊：
影响因子：
3.7
通讯作者：
Stelmachowicz, Patricia G.
中科院分区：
文献类型：
--
作者：
Alexander, Joshua M.;Kopun, Judy G.;Stelmachowicz, Patricia G.
目的：作者已经证明，与传统助听器放大相关的有限带宽阻止了有用的高频语音信息的传输。本研究的目的是研究两种流行的频率降低算法和一种新的算法（频谱包络抽取）在轻度至中度感音神经性听力损失的成年人和正常的听力controls.Design：参与者单耳通过耳机听录音的9个摩擦音和破擦音由三名妇女在一个元音，辅音背景。将刺激与10 dB SNR的语音形状噪声混合，并通过Widex Inteo IN-9和Phonak Naida UP V耳后（BTE）助听器记录。频率变换（FT）用于Inteo，非线性频率压缩（NFC）用于Naida。两种器械均被程控为低于4 kHz的频率，但两种器械均不能低于6至7 kHz的频率。每个设备都在四种条件下进行测试：频率降低停用（FT关闭和NFC关闭），频率降低激活（FT和NFC），宽带（WB）和每个助听器特有的第四种条件。WB条件是通过将来自第一条件的记录与源刺激的高通滤波版本混合来构建的。对于Inteo，第四个条件包括使用与第一个条件相同的设置进行的记录，但激活了降噪功能（FT关闭）。对于Naida，第四个条件与第一个条件相同，不同之处在于源刺激由一种新颖的频率压缩算法（在MATLAB中设计的频谱包络抽取（SED））进行预处理，该算法允许更完全地降低4至10 kHz的输入频带。NFC的后续实验使用峰力的Naida SP V BTE，这也可以降低更大范围的输入frequency.Results：对于正常听力和听力受损的听众，与FT的性能显着恶化相比，在其他条件。与以前的研究结果一致，听力受损的听众在WB条件下的性能显着优于FT关闭条件。此外，SED和WB条件下的性能均显著优于NFC关闭条件和NFC条件（输入带宽为6 kHz）。SED和WB之间没有显著差异，表明通过增加带宽获得的摩擦音识别的改善也可以使用这种形式的频率压缩来获得。大多数条件之间的显着差异可能主要归因于音素/s/和/z/混淆的增加或减少。在后续实验中，在NFC条件下，10 kHz输入带宽的性能明显优于NFC关闭，复制了SED获得的结果。此外，听众谁表现不佳与NFC关闭往往表现出最大的改善与nfc.Conclusions：改善识别的刺激选择敏感的频率降低的影响已被证明使用两种形式的频率压缩（NFC和SED）在个人轻度至中度高频感音神经性听力损失。然而，阴性结果警告不要对该人群使用FT。结果还表明，当起始频率>= 4 kHz时，此处和其他地方报告的扩展带宽的优点适用于频率压缩（NFC/SED）的输入带宽。
Objectives: The authors have demonstrated that the limited bandwidth associated with conventional hearing aid amplification prevents useful high-frequency speech information from being transmitted. The purpose of this study was to examine the efficacy of two popular frequency-lowering algorithms and one novel algorithm (spectral envelope decimation) in adults with mild to moderate sensorineural hearing loss and in normal-hearing controls.Design: Participants listened monaurally through headphones to recordings of nine fricatives and affricates spoken by three women in a vowel-consonant context. Stimuli were mixed with speech-shaped noise at 10 dB SNR and recorded through a Widex Inteo IN-9 and a Phonak Naida UP V behind-the-ear (BTE) hearing aid. Frequency transposition (FT) is used in the Inteo and nonlinear frequency compression (NFC) used in the Naida. Both devices were programmed to lower frequencies above 4 kHz, but neither device could lower frequencies above 6 to 7 kHz. Each device was tested under four conditions: frequency lowering deactivated (FT-off and NFC-off), frequency lowering activated (FT and NFC), wide-band (WB), and a fourth condition unique to each hearing aid. The WB condition was constructed by mixing recordings from the first condition with high-pass filtered versions of the source stimuli. For the Inteo, the fourth condition consisted of recordings made with the same settings as the first, but with the noise-reduction feature activated (FT-off). For the Naida, the fourth condition was the same as the first condition except that source stimuli were preprocessed by a novel frequency compression algorithm, spectral envelope decimation (SED), designed in MATLAB, which allowed for a more complete lowering of the 4 to 10 kHz input band. A follow-up experiment with NFC used Phonak's Naida SP V BTE, which could also lower a greater range of input frequencies.Results: For normal-hearing and hearing-impaired listeners, performance with FT was significantly worse compared with that in the other conditions. Consistent with previous findings, performance for the hearing-impaired listeners in the WB condition was significantly better than in the FT-off condition. In addition, performance in the SED and WB conditions were both significantly better than in the NFC-off condition and the NFC condition with 6 kHz input bandwidth. There were no significant differences between SED and WB, indicating that improvements in fricative identification obtained by increasing bandwidth can also be obtained using this form of frequency compression. Significant differences between most conditions could be largely attributed to an increase or decrease in confusions for the phonemes /s/ and /z/. In the follow-up experiment, performance in the NFC condition with 10 kHz input bandwidth was significantly better than NFC-off, replicating the results obtained with SED. Furthermore, listeners who performed poorly with NFC-off tended to show the most improvement with NFC.Conclusions: Improvements in the identification of stimuli chosen to be sensitive to the effects of frequency lowering have been demonstrated using two forms of frequency compression (NFC and SED) in individuals with mild to moderate high-frequency sensorineural hearing loss. However, negative results caution against using FT for this population. Results also indicate that the advantage of an extended bandwidth as reported here and elsewhere applies to the input bandwidth for frequency compression (NFC/SED) when the start frequency is >= 4 kHz.