Comparison of Speech Perception in Background Noise With Acceptance of Background Noise in Aided and Unaided Conditions

Abstract

Background noise is a significant factor influencing hearing-aid satisfaction and is a major reason for rejection of hearing aids. Attempts have been made by previous researchers to relate the use of hearing aids to speech perception in noise (SPIN), with an expectation of improved speech perception followed by an increased acceptance of hearing aids. Unfortunately, SPIN was not related to hearing-aid use or satisfaction. A new measure of listener reaction to background noise has been proposed. The acceptable noise level (ANL), expressed in decibels, is defined as a difference between the most comfortable listening level for speech and the highest background noise level that is acceptable when listening to and following a story. The ANL measure assumes that speech understanding in noise may not be as important as is the willingness to listen in the presence of noise. It has been established that people who accept background noise have smaller ANLs and tend to be "good" users of hearing aids. Conversely, people who cannot accept background noise have larger ANLs and may only use hearing aids occasionally or reject them altogether. Because this is a new measure, it was important to determine the reliability of the ANL over time with and without hearing aids, to determine the effect of acclimatization to hearing aids, and to compare the ANL to well-established measures such as speech perception scores collected with the SPIN test. Results from 50 listeners indicate that for both good and occasional hearing aid users, the ANL is comparable in reliability to the SPIN test and that both measures do not change with acclimatization. The ANLs and SPIN scores are unrelated. Although the SPIN scores improve with amplification, the ANLs are unaffected by amplification, suggesting that the ANL is inherent to an individual and can be established prior to hearing aid fitting as a possible predictor of hearing-aid use.

Acceptable noise level: Repeatability with Danish and non-semantic speech materials for adults with normal hearing

“…Previous studies concluded that ANL is an individual inherent feature, unaffected by factors like age and degree of hearing loss (Nabelek et al, 2004;Nabelek et al, 2007). In the present study no systematic differences were seen between the ANL on right and left ear.…”

“…That would imply that the ANL test has too poor repeatability to predict individual patterns of future hearing aid use. In the already mentioned letter to the editor, Nabelek et al (2007) also reported that in a study (Nabelek et al, 2004), the test-retest difference for individual hearing-impaired listeners was approximately 2 dB. This value was not directly reported in the original paper (Nabelek et al, 2004), but figure 1 in the paper shows testretest differences of about 0-4 dB.…”

“…In the already mentioned letter to the editor, Nabelek et al (2007) also reported that in a study (Nabelek et al, 2004), the test-retest difference for individual hearing-impaired listeners was approximately 2 dB. This value was not directly reported in the original paper (Nabelek et al, 2004), but figure 1 in the paper shows testretest differences of about 0-4 dB. These differences are much smaller than the individual differences found in the present study, and it seems that this paper would have demonstrated a strong CR.…”

“…Earlier studies of normal-hearing and hearing-impaired adult subjects have shown a high correlation between ANL measurements obtained at three different sessions (Nabelek et al, 2004;Freyaldenhoven et al, 2006). In the study by Nabelek et al (2004) the time between the first and the second session was one month and between the second and the third session it was two months. In the study by Freyaldenhoven et al (2006) the intersession time was approximately 1 week.…”

“…The ANL in dB is the difference between the MCL for running speech and the highest background noise level (BNL) that is acceptable when following the running speech (Nabelek et al, 2004). ANL has been used for prediction of individual hearing aid use patterns (full time use or occasional use/no use at all), and has also been used to assess the benefit of hearing aid algorithms for reduction of background noise (Freyaldenhoven et al, 2005a;Mueller et al, 2006).…”