Speech Recognition at the Acceptable Noise Level.

Abstract

The acceptable noise level (ANL) has been proposed as a prehearing aid fitting measure that could be used for hearing aid selection and counseling purposes. Previous work has demonstrated that a listener's ANL is unrelated to their speech recognition in noise abilities. It is unknown what criteria a listener uses when they select their ANL. To date, no research has explored the amount of speech recognized at the listener's ANL. To examine the amount of speech recognized at the listener's ANL to determine whether speech recognition in noise is utilized as a factor for setting ANL. A descriptive quasi-experimental study was completed. For all listeners, ANL was measured and speech recognition in noise was tested at ANL and at two additional signal-to-noise ratio (SNR) conditions based on the listener's ANL (ANL + 5 and ANL - 5). Forty-four older adults served as participants. Twenty-seven participants had normal hearing and seventeen participants had mild to moderately-severe, symmetrical, sensorineural hearing loss. Acceptance of noise was calculated from the measures of most comfortable listening level and background noise level. Additionally, speech recognition in noise was assessed at three SNRs using the quick speech-in-noise test materials. A significant interaction effect of SNR condition and ANL group occurred for speech recognition. At ANL, a significant difference in speech recognition in noise was found across groups. Those in the mid and high ANL groups had excellent speech recognition at their ANL. Speech recognition in noise at ANL decreased with ANL category. For listeners with mid and high ANLs, speech recognition appears to play a primary role in setting their ANL. For those with low ANLs, speech recognition may contribute to setting their ANL; however, it does not appear to be the primary determiner of ANL. For those with very low ANLs, speech recognition does not appear to be significant variable for setting their ANL.