Aided Acceptable Noise Levels (ANL): A Comparison across Degree of Hearing Loss, Noise Reduction in Hearing Aid and Personality Type

Abstract

Acceptable Noise Level (ANL) is a measure of the willingness to accept the background noise while listening to speech and is defined as the difference between the most comfortable listening level (MCL) for running speech and the maximum background noise level (BNL) that a listener is willing to accept. The present study aimed to evaluate the relationship between the unaided and aided Acceptable Noise Levels, effect of degree of hearing loss , digital hearing aid with and without the noise reduction scheme, effect of presentation level and effect of personality type on Aided Acceptable Noise Levels. Three groups of participants based on the degree of hearing loss were assessed in unaided and two aided conditions. The two aided conditions included fitting of an appropriate digital hearing aid with noise-reduction feature turned-off and turned-on. To assess the effect of presentation level, only participants with the moderate degree were considered. The ANLs were obtained at three presentation levels, at 5 dB SL, mid-value of DR and 10 dB below the UCL. Eysenck Personality Questionnaire (EPQ) was administered to assess personality of the participant. The results indicated that: 1. ANLs obtained in the unaided and aided conditions were not significantly different. 2. The difference in ANLs across the severity of hearing loss was non-significant, indicating that ANLs are not affected by the peripheral hearing loss. 3. Digital noise-reduction feature significantly decreased the ANL by increasing the amount of tolerance to background noise. 4. When ANL was measured at different presentation levels of speech, there was a gradual increment in the ANL with increase in the presentation level. 5. On personality assessment, the higher extroverted personality obtained a lower ANL while the participant high on neuroticism obtained a higher ANL.