Validation of the Italian version of the Acceptable Noise Level Test

Background: The Acceptable Noise Level (ANL) test was developed by Nabelek A. et al in the early 1990s; it is a measure of noise tolerance and has been proposed as a predictor for successful hearing aid use. Aim of this work is to validate the Italian version of ANL test in adults. Materials and methods: ANL was determined in normal hearing subjects and in hearing aid (HA) users, affected by mild to severe bilateral cochlear hearing loss. All subjects underwent otomicroscopy, pure-tone and speech audiometry with and without HA and immitance audiometry. Test-retest has been performed after 15 days in normal hearing and hearing impaired subjects. Ninety subjects with HA has been tested and divided in two groups according to the outcome at International Outcome Inventory for hearing aids. In a subgroup of 10 of “unsatisfied“ subjects, ANL was also tested with optimization of fitting with new HA. Results: Test-retest reliability was high (intraclass correlation coefficient was 0.95; interval of confidence: 0,88-0,98). ANL values were higher in hearing impaired subject (with and without HA) compared to normal hearing subjects. (p<0,001) The use of HA significantly varies the ANL values of each subject, independent by the grade of hearing loss. (p<0,001) In accordance with literature, no significant correlation was found between IOI_HA and ANL values. Conclusion: The Italian version of ANL was shown to be an accurate and sensitive tool in rehabilitation with HA and proved to give comparable results to the other languages’s data reported in literature.