PP705 - Noise Acceptance and Preferred Listening Level Under Different Noise Conditions

Abstract:
This study assessed individuals' acceptable noise levels (ANL) and preferred listening levels (PLL) in various noise conditions. Fifty-seven subjects with normal hearing and who were native English speakers participated. The ANL was measured with both speech and music targets under four different noise conditions: multi-talker background, vehicle noise, indoor activity, and echoing crowd noise. Preliminary results indicated that ANL and PLL for speech and music targets significantly differed across the varying noise conditions. These results suggest different mechanisms may underlie the ANL and PLL depending on the target and noise stimuli used to measure the responses.

Summary:
Rationale/Purpose
Individuals have varying tolerances and preferences for noise when listening to speech and music as measured on the Acceptable Noise Level (ANL) test. Previous ANL studies have typically relied on limited noise samples, though, which may not fully cover an individual's noise tolerance and preferred listening level (PLL) for different noises that listeners often encounter in daily life. Therefore, this study addresses this gap by measuring ANL and PLL to speech and music targets in the presence of varying noises that reflect everyday listening conditions. The first aim was to examine whether an individual’s ANL is related to their PLL and hidden hearing loss (HHL). The second aim was to identify if ANL and PLL differ across the different noise conditions. Understanding an individual's noise tolerance and preference levels in various noise situations can help identify patterns that may contribute to an individual's vulnerability to noise-induced hearing loss (NIHL) and HHL.

Methods
Fifty-seven subjects with normal hearing, all native English speakers, participated in the study. The ANL was measured using two targets: speech (Arizona Travelogue) and music (the song Flowers), and four different types of noise: multi-talker babble, vehicle, indoor activity, and echoing crowd noise. These noises were selected because individuals commonly encounter them in everyday life. For ANL, subjects first selected their most comfortable level (MCL) for the targets. Then, the varying noises were added. The subject changed the noise level until the maximum tolerated noise level was reached while listening to the target sounds. For PLL, subjects listened to background noise at fixed levels of 60 and 70 dBA and adjusted the preferred listening level of each target. ANL and PLL were calculated as the difference between the MCL (or PLL) and the background noise level (BNL). Extended high frequency (EHF) was measured from 9-kHz to 16-kHz for both ears. Pearson correlation coefficient was used to investigate the relationship between ANL, PLL, and HHL, and a mixed ANOVA was used to investigate the effect of different noise conditions on ANL and PLL.

Results
Preliminary results indicate that the ANL for speech and music targets significantly differed across the four noise conditions (p < 0.05). The PLL for speech and music targets differed significantly across the four noise conditions (p < 0.05). ANL did not correlate with the PLL and HHL.

Conclusion
ANL for both targets was highest when listening to babble noise, while ANL was lowest when listening to non-speech noise, indicating that individuals have a lower tolerance for noise that contains speech sounds. The lack of correlation between ANL and PLL may be attributed to methodological variations and applying different mechanisms depending on the targets and particular noise types.

Future goals
This study is ongoing, and data collection (target: 90 subjects) will be complete by February 2025. This study aims to identify people at risk for NIHL and HHL in real-world settings by using a larger sample and expanding the previously limited range of noise types.