Lunner T, Hellgren J, Arlinger S, Elberling C
Department of Otorhinolaryngology, Linköping University, Sweden.
Ear Hear. 1997 Feb;18(1):12-25. doi: 10.1097/00003446-199702000-00002.
In a series of experiments with a wearable binaural digital hearing aid, two hearing aid processing algorithms were compared. Both algorithms provided individual frequency shaping via a seven-band filterbank with compression limiting in the high-frequency channel. They differed in the processing of the low-frequency channel, using dynamic range compression for one (DynEar) and linear processing with compression limiting for the other (LinEar). In a pilot field test we found that LinEar/ DynEar preference based on use time could be predicted from auditory dynamic range data. For the subjects who preferred DynEar, the mean dynamic range was broader for low and mid frequencies and narrower for high frequencies, as compared with the LinEar preference subjects. These groupings were tested as predictors of user preference and performance in a main field test.
The main study included 26 hearing aid users with symmetrical sensorineural losses. The algorithms were compared in a one-mo-long blind field test. A data logger function was included for objective recording of the total time each algorithm was used and how the volume controls were used. The preference was based on the time used for each algorithm and on subjective statements. Threshold signal-to-noise ratio (S/N-threshold) for speech was tested, and sound quality ratings were obtained through a questionnaire. We also tested the S/N-thresholds for the subjects' conventional (own) aids.
The preference was correctly predicted by the dynamic range data on 12 out of 15 new cases. S/N-thresholds were lower for the preferred fittings compared with the nonpreferred fittings and with the subjects' own aids. In the questionnaire the preferred fittings were rated significantly higher in terms of overall impression and clearness. Because of the systematic way the DynEar-preference subjects adjusted the high-frequency DynEar gain, we speculate that upward spread of masking may have been a factor in preference and performance. Additionally, LinEar-preference subjects' preference and performance might have been influenced by excessive compression ratios with the DynEar processing in these cases.
在一系列使用可穿戴双耳数字助听器的实验中，对两种助听器处理算法进行了比较。两种算法均通过一个七频段滤波器组提供个体频率整形，并在高频通道中进行压缩限制。它们在低频通道的处理上有所不同，一种使用动态范围压缩（DynEar），另一种使用带压缩限制的线性处理（LinEar）。在一项初步现场测试中，我们发现基于使用时间的LinEar/DynEar偏好可以从听觉动态范围数据中预测出来。与偏好LinEar的受试者相比，偏好DynEar的受试者在低频和中频的平均动态范围更宽，而在高频则更窄。在一项主要现场测试中，对这些分组作为用户偏好和性能的预测指标进行了测试。
主要研究纳入了26名患有对称性感音神经性听力损失的助听器用户。在一项为期一个月的盲法现场测试中对这两种算法进行了比较。包含一个数据记录功能，用于客观记录每种算法的总使用时间以及音量控制的使用方式。偏好基于每种算法的使用时间和主观陈述。测试了言语的阈值信噪比（S/N阈值），并通过问卷调查获得了音质评分。我们还测试了受试者传统（自己的）助听器的S/N阈值。
在15个新病例中的12个病例中，动态范围数据正确预测了偏好。与非偏好的助听器以及受试者自己的助听器相比，偏好的助听器的S/N阈值更低。在问卷调查中，偏好的助听器在总体印象和清晰度方面的评分显著更高。由于偏好DynEar的受试者以系统的方式调整高频DynEar增益，我们推测掩蔽效应的向上扩展可能是偏好和性能的一个因素。此外，在这些情况下，LinEar偏好受试者的偏好和性能可能受到DynEar处理中过高压缩比的影响。
