The challenge of detecting minimal hearing loss in audiometric surveys

Purpose: This tutorial provides framework and context for understanding the complex interaction of hearing measurement methodology and cohort social factors, as well as their relation to approaches to data interpretation and identification of minimal hearing loss (HL) in audiometric surveys. Method: Pertinent archival studies were reviewed, and an original analysis on U.S. Centers for Disease Control and Prevention (CDC) audiometric survey data from children (ages 6-19) was performed. Conclusion: The definition of an otologically normal individual, the pass-fail criterion representing the upper limit of the range of normal hearing, and the quality of the audiometry affect the percentage of persons who are falsely identified as having a minimal HL. An upper limit of normal hearing of 15 dB HL yields an unacceptably high false-positive rate, particularly when the more variable higher audiometric frequencies are examined. When air-conduction thresholds are assessed in isolation to estimate potential noise damage, the failure to exclude persons who have possible middle and external ear problems, including earwax, results in high false-positive rates. When these factors and other limitations are considered, audiograms from teens from a recent CDC survey do not show evidence consistent with widespread noise-induced HL. Suggestions are made to improve the effectiveness of pure-tone audiometry and the identification of minimal HL.