Americans Hear as Well or Better Today Compared With 40 Years Ago: Hearing Threshold Levels in the Unscreened Adult Population of the United States, 1959–1962 and 1999–2004 Hoffman, Howard J.; Dobie, Robert A.; Ko, Chia-Wen; More Hoffman, Howard J.; Dobie, Robert A.; Ko, Chia-Wen; Themann, Christa L.; Murphy, William J. Less Ear and Hearing. 31(6):725-734, December 2010. Abstract Abstract In Brief In Brief Favorites PDF Get Content & Permissions Abstract: In Brief: Hearing threshold data are presented from a nationally representative survey in the United States (National Health and Nutrition Examination Survey, 1999–2004) in a format that could replace Annex B in international (ISO-1999) and national (ANSI S3.44) standards. The recent data are compared with older survey data (National Health Examination Survey I, 1959–1962) on which Annex B is based. For men and women, high-frequency hearing thresholds were lower (better) in 1999–2004 than that in 1959–1962. The prevalences of hearing impairment were also lower in the recent survey. Differences seen at 500 Hz are probably attributable in part to changes in standards for ambient noise in audiometry.