Preminger J E, Neuman A C, Bakke M H, Walters D, Levitt H
Rehabilitation Engineering Research Center on Hearing Enhancement and Assistive Devices, Graduate School, City University of New York, New York, USA.
Ear Hear. 2000 Jun;21(3):177-93. doi: 10.1097/00003446-200006000-00001.
The practical importance of the simplex procedure, a subjective technique used to refine the frequency gain characteristic (FGC) of a hearing aid according to listener preference, was determined for individual listeners by measuring hearing aid benefit using both laboratory studies and field studies.
A digital research hearing aid with two memories was used as the test hearing aid. The modified simplex procedure was used to select the FGC judged to yield the best speech clarity in the presence of low-level vent noise and again in higher-level cafeteria noise by 10 experienced hearing aid users. The FGCs assessed by the listeners varied systematically from The National Acoustic Laboratories Revised (NAL-R) response in the amount of low-frequency or high-frequency amplification. The benefit obtained with these two simplex-selected settings was compared with that obtained using the NAL-R FGC. Measures of benefit included speech recognition testing in the laboratory and ratings of speech intelligibility in the field. In the first field study, the two simplex settings were compared. In the second field study, the simplex-selected setting for higher level noise and the NAL-R setting were compared.
In the laboratory, the majority of listeners selected an increase in the low-frequency channel gain compared with the NAL-R. Desired high-frequency channel gain was correlated with degree of hearing loss and type of background noise. The benefit as measured using nonsense syllables did not differ significantly among the three fittings, but differences in benefit were measurable with the rating procedure. Five of eight participants noticed a significant difference in their speech understanding in the real world for the FGCs selected in different background noises. Two of seven participants reported significantly better speech intelligibility with a simplex-selected FGC compared with the NAL-R FGC in the real world. The remaining subjects reported similar speech understanding capabilities with both hearing aid settings.
The majority of subjects included in this study selected an FGC with real ear insertion gain different than the NAL-R prescription to improve subjective speech understanding in the laboratory. A small number of these listeners rated the selected FGC as providing improved speech intelligibility over the NAL-R FGC in the real world. This finding indicates that the simplex procedure should be used selectively to modify the NAL-R prescription. A screening technique would be useful in selecting those who might benefit from a modified fitting. The simplex procedure may also prove to be useful in selecting listeners who would benefit from multiple memory hearing aids.
通过实验室研究和实地研究测量助听器益处，确定单纯形法（一种根据听众偏好来优化助听器频率增益特性（FGC）的主观技术）对个体听众的实际重要性。
使用具有两个记忆功能的数字研究型助听器作为测试助听器。10名经验丰富的助听器使用者采用改良单纯形法，在低水平通气噪声以及更高水平的自助餐厅噪声环境下，选择被认为能产生最佳言语清晰度的FGC。听众评估的FGC在低频或高频放大程度上与澳大利亚国家声学实验室修订版（NAL-R）响应存在系统性差异。将这两种通过单纯形法选择的设置所获得的益处与使用NAL-R FGC所获得的益处进行比较。益处的衡量指标包括实验室中的言语识别测试以及实地的言语可懂度评分。在第一项实地研究中，对两种单纯形设置进行比较。在第二项实地研究中，对针对更高水平噪声的单纯形法选择设置与NAL-R设置进行比较。
在实验室中，与NAL-R相比，大多数听众选择增加低频通道增益。期望的高频通道增益与听力损失程度和背景噪声类型相关。使用无意义音节测量的益处在三种适配设置之间没有显著差异，但通过评分程序可以测量到益处的差异。八名参与者中有五人注意到，在现实世界中，针对不同背景噪声选择的FGC在言语理解方面存在显著差异。七名参与者中有两名报告称，在现实世界中，与NAL-R FGC相比，单纯形法选择的FGC的言语可懂度明显更好。其余受试者报告称，两种助听器设置下的言语理解能力相似。
本研究中的大多数受试者选择了实际耳插入增益与NAL-R处方不同的FGC，以改善实验室中的主观言语理解。其中少数听众认为，在现实世界中，所选FGC比NAL-R FGC提供了更好的言语可懂度。这一发现表明，应选择性地使用单纯形法来修改NAL-R处方。一种筛选技术将有助于选择那些可能从修改后的适配中受益的人。单纯形法在选择可能从多记忆功能助听器中受益的听众方面可能也很有用。
