This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.
HE PRESENT reference level "O db" on American audiometers was derived from studying "normal" individuals in a national hearing survey in 1936. Since this was an average value, some subjects had better than average normal hearing, causing some otologists to complain that it was awkward to express a hearing loss as − 5 or −10 db. It was also cumbersome to have to speak in terms of hearing loss rather than residual hearing. In view of these complaints and because the reference hearing level used in some European countries was lower (or better) than the American standard, the International Standards Organization, of which the American Standards Organization is the US member body, undertook to study the problem. It proposed recently that the American standard be changed to conform to the European standard.
In order to change an American standard, various member organizations in this country must approve the proposed modifications.