A multi-site evaluation of a proposed test for verifying hearing aid maximum output

The aim of this study was to evaluate a clinical test proposed to verify the output setting of hearing aids. Across three test sites, 56 bilaterally fitted hearing aid users were recruited. They answered questions about real-life loudness discomfort experiences and then completed the output verification test. Using an ascending method, a 1,500 kHz narrowband noise and a selection of broadband environmental noises were presented in 5 dB steps from 80 to 90 dB SPL. Response options included 'acceptably loud', and 'uncomfortably loud'. A swept pure tone presented at 90 dB SPL was also administered. Some loudness discomfort was reportedly experienced in real life by 82% of the participants. Generally, the test noises produced low specificity, with the 1,500 kHz narrowband noise being the best predictor of loudness discomfort experiences in real life, while the swept pure tone showed low sensitivity. Individual reactions to specific sounds and the test equipment and environment used are argued to affect the laboratory performance. A better understanding of these factors is needed before the test can be improved.