Storey L, Dillon H, Yeend I, Wigney D
National Acoustic Laboratories, Chatswood, Australia.
Ear Hear. 1998 Aug;19(4):267-79. doi: 10.1097/00003446-199808000-00002.
The primary aim of this study is to evaluate the accuracy of a new procedure for selecting the saturation sound pressure level (SSPL) of hearing aids. Secondary aims are to investigate what limits the minimum SSPL that is acceptable to clients and whether the type of limiting (peak clipping or compression limiting) affects the SSPL required.
The study comprised two experiments. In the first, subjects increased the SSPL of a laboratory master hearing aid until they experienced loudness discomfort and decreased it until the sound became less acceptable in some way. In the second study, subjects wore multi-memory programmable hearing aids in their own environments and reported which of the two programs, differing only in SSPL setting, provided the more acceptable sound quality and comfort.
The theoretical procedure being investigated prescribed SSPLs that were within the acceptable range for 86% of the subjects in the laboratory study and for 63% of the subjects in the field experiment. On average, the theoretical predictions were neither too high nor too low. Incorporating individual measurements of loudness discomfort level into the prescription formula increased accuracy by such a small amount that it was not considered worthwhile. For a compression limiting hearing aid, the first thing that subjects noticed as SSPL was reduced was inadequate loudness. For the peak clipping hearing aid, however, both inadequate loudness and perception of distortion limited the acceptable SSPL range.
The theoretical procedure provides a good initial prescription of three frequency average SSPL, but it is still essential to evaluate the fitting and, if necessary, fine tune the individual's hearing aid. Compression limiting hearing aids can have slightly lower SSPL settings than peak clipping hearing aids for the same acceptability.
本研究的主要目的是评估一种选择助听器饱和声压级（SSPL）的新程序的准确性。次要目的是调查限制客户可接受的最小SSPL的因素，以及限制类型（峰值削波或压缩限制）是否会影响所需的SSPL。
该研究包括两个实验。在第一个实验中，受试者提高实验室主助听器的SSPL，直到他们感到响度不适，然后再降低它，直到声音在某种程度上变得不那么可接受。在第二个研究中，受试者在自己的环境中佩戴多记忆可编程助听器，并报告仅在SSPL设置上不同的两个程序中哪一个提供了更可接受的音质和舒适度。
在实验室研究中，被研究的理论程序规定的SSPL在86%的受试者可接受范围内，在现场实验中这一比例为63%。平均而言，理论预测既不过高也不过低。将响度不适水平的个体测量纳入处方公式，准确性提高的幅度很小，因此认为不值得。对于压缩限制助听器，随着SSPL降低，受试者首先注意到的是响度不足。然而，对于峰值削波助听器，响度不足和失真感都限制了可接受的SSPL范围。
该理论程序为三个频率的平均SSPL提供了一个良好的初始处方，但评估助听器的适配情况并在必要时对个体助听器进行微调仍然至关重要。对于相同的可接受性，压缩限制助听器的SSPL设置可能比峰值削波助听器略低。
