Widex A/S, Lynge, Denmark.
Ear Hear. 2022;43(6):1771-1782. doi: 10.1097/AUD.0000000000001239. Epub 2022 Jun 23.
Today, approximately 70 to 80% of hearing aid fittings are made with silicone instant ear tips rather than custom earmolds. Nevertheless, little is known about the impact of instant ear tips on the acoustic coupling between the hearing aid receiver and the individual ear canal, even though it can have a major impact on the overall sound of the hearing aids. This study aimed to investigate the acoustic properties of different instant ear tip types and their across-subject variability, the within-subject reliability of those properties, and the influence of the users' level of experience with ear-tip insertion on the acoustics. Furthermore, subjective ratings of occlusion produced by the ear tips were considered.
Five types of instant ear tips (Open, Tulip, Round [2-vent], Round [1-vent], Double Domes) provided by the hearing aid manufacturer Widex were considered in this study. Probe-microphone measurements were performed at the eardrums of 30 participants (60 ears). In the first experiment, the real ear occluded insertion gain and the vent effect (VE) were measured, and the listeners rated the subjective occlusion experienced with each ear tip. In the second experiment, the same measurements were repeated six times per participant. The within-subject variability of the acoustic ear tip properties was investigated as well as the impact of the degree of users' experience with ear tip insertion on the resulting real ear measurements.
All tested ear tips were, on average, acoustically transparent up to 1 kHz except Double Domes, which were only transparent up to 600 Hz. Distinct VE profiles were found for each ear tip type, but a large across-subject variability was observed for both real ear occluded insertion gain and VE. However, the within-subject reliability was high. The measured VE was highly correlated with the perceived occlusion. Finally, no significant effect of the level of experience in ear tip insertion on the acoustic properties of the ear tips was found, but the within-subject variability was larger in the less experienced group.
These results suggest that the acoustic properties of instant ear tips and their coupling to the individual ear canal impact the resulting hearing aid fitting and should be considered by the hearing care professionals and reflected in the fitting software. The high within-subject reliability indicates that the ear tip acoustics remain stable for the individual in daily use. Finally, real ear measurements should be considered an essential part of the hearing aid fitting process in clinical practice to ensure an optimal fit for the individual hearing aid user.
如今，大约有 70%到 80%的助听器适配采用的是硅酮即时耳塞，而非定制耳模。然而，尽管即时耳塞对助听器接收器和个体耳道之间的声耦合有重大影响，但人们对其知之甚少。本研究旨在探究不同即时耳塞类型的声学特性及其个体间变异性、这些特性的个体内可重复性，以及使用者在耳塞插入方面的经验水平对声学的影响。此外，还考虑了耳塞产生的封闭感的主观评价。
本研究考虑了助听器制造商 Widex 提供的 5 种即时耳塞（Open、Tulip、Round [2-vent]、Round [1-vent]、Double Domes）。在第一个实验中，对 30 名参与者（60 只耳朵）的鼓膜进行了探管麦克风测量，测量了真耳封闭插入增益和通气效应（VE），并让听众对每种耳塞的主观封闭感进行了评价。在第二个实验中，每个参与者重复了六次相同的测量。研究了声学耳塞特性的个体内可变性，以及使用者在耳塞插入方面的经验水平对真耳测量结果的影响。
除了 Double Domes 之外，所有测试的耳塞在 1kHz 以下的平均声学传输率都很高，在 600Hz 以下只有 Double Domes 是透明的。每种耳塞类型都有明显的 VE 曲线，但真耳封闭插入增益和 VE 的个体间变异性都很大。然而，个体内可重复性很高。测量的 VE 与感知的封闭感高度相关。最后，没有发现使用者在耳塞插入方面的经验水平对耳塞的声学特性有显著影响，但在经验较少的组中，个体内变异性更大。
这些结果表明，即时耳塞的声学特性及其与个体耳道的耦合会影响最终的助听器适配，应引起听力保健专业人员的重视，并反映在适配软件中。个体内可重复性高表明，在日常使用中，耳塞的声学特性对个体保持稳定。最后，真耳测量应被视为临床实践中助听器适配过程的一个重要组成部分，以确保为个体助听器使用者提供最佳适配。
