Self-adjustment of Hearing Aid Amplification: Listener Preferences and Speech Recognition Performance

Abstract

Self-adjustment of amplification parameters is a potential method for improving satisfaction with hearing aids, particularly in noisy environments. People with mild-to-moderate hearing loss adjusted gain parameters in quiet and in several types of noise by using a simple touchscreen interface to control a research device which emulated the basic functionality of a digital hearing aid in real time. Results of self-adjustment indicated reliable individual preferences but a great deal of between-listener variability, indicating that people have stable preferences for amplification and are able to select preferred parameters consistently. The large individual differences suggest that preferred gain configurations can differ greatly from prescriptive settings in both quiet and in noise and underscore the need for an efficient method of customizing amplification parameters beyond prescribed settings. Audiological listener factors such as age, hearing loss, and experience using hearing aids, predicted little of the between-listener variability. It is unlikely that modifications to prescriptive fitting formulae based on the factors examined here would result in amplification parameters that are similar to user-customized settings. Most self-adjustments were completed in only a minute or two, demonstrating that self-adjustment is a rapid and efficient method for matching hearing aid output to preferred settings. When self-adjustments were made with speech presented at average conversational levels, gain adjustments did not strongly affect speech recognition within the range of signal-to-noise ratios tested. For speech at a lower presentation level, preferences for amplification were related to speech recognition performance, suggesting that listeners include their subjective sense of speech clarity among their criteria for selecting amplification parameters during self-adjustment. Self-adjusted amplification was overwhelmingly rated as satisfactory or very satisfactory and as producing a comfortable loudness. Taken together, the results of these experiments support the conclusion that for people with mild-to-moderate hearing loss, self-adjustment is likely to produce satisfactory and comfortable amplification that provides speech recognition comparable to that of hearing aids fit according to current clinical best practices.