Individual Variability in Unaided and Aided Measurement of the Acceptable Noise Level
22 April 2013 (online)
The acceptable noise level (ANL) is a measure of the maximum background noise level a person is willing to tolerate for a long period of time while listening to running speech. Previous research indicates that the ANL may be useful in predicting hearing aid usage patterns. Such predictions could be very helpful in the aural rehabilitation process. Despite early reports of strong repeatability, recent reports have questioned the utility of the ANL test based on poor test repeatability. Another hallmark of the ANL test is substantial variability across subjects both within and across studies. Variability was considered here in terms of intrasubject test repeatability and individual differences in ANL under unaided and aided conditions. To reduce variability, a fixed speech presentation level was used. Instructions were scripted and delivered in visual and auditory modes prior to testing and in a corresponding visual mode during testing. Instruction and testing was under computer control to optimize consistency. Results indicated high intrasubject, intrasession repeatability. ANL values differed widely across subjects in unaided and aided conditions, consistent with a large number of previous investigations.