Calibration and Working Condition of 100 Audiometers

Abstract

A CCURACY in determining auditory thresholds is crucial for identifying persons with decreased hearing acuity, particularly in view oif the ever-expaniding growth of hearing conservatio,n programs, diagno,stic clinics, and the increased. use of industrial and military audiometry. The results of hearing tests are important in determining the necessity for medical treatment, educational pla,cement, acceptability for employment or militaryservice, and the advisibility of a hearing aid. The accuracy of hearing te,sts is directly related to a number of factors, such as the training and experience of the operator, environrmental noise, and the cooperation and attention of the subject. Of equal importance is the state of calibration of the audiometer. Calibration is particularly relevant as the accuracy of an audiometer, like all electronic equipment, is subject to damage, aging, component malfunction, and change due to normal use. It is generally agreed that the calibration of audiometers should be checked periodically, although there is no agreement as to how frequently they should be checked. Two, sets of specifications', developed in the 1950's, describe the characteristics that are considered essential fo,r audiometers,. The specifications adopted by the Council on Physical Medicine and Rehabilitation of the, American Medical Association (AMA) and the Americaan Standards Association (ASA) were completed at iapproximately the same time, and several members of each association served concurrently oln both conunittees. The two sets, olf specifications do not differ appreciably except that those of the ASA are slightly more detailed. The two organizations have adopted specifications for pure tone audiometers for screening purposes (1), audiometers for general diagnostic purposes (2), and speech audiometers (3). (Standards approved as ASA standards are now designated as USA standards; there is no change in the index identification or technical content.) In December 1963 the committee on conserva,tion of hearing of the American Academy of Ophthalmology and Otolaryngolo,gy voted to adopt the International Organization of StandDr. Thomas is director of the hearing and speech center, and Mr. Preslar is research associate, department of surgery, University of North Carolina, Chapel Hill. Dr. Summers is assistant chief, training grants and awards branch, National Institute of Neurological Diseases and Stroke, and Dr. Stewart is consultant in audiology and speech pathology, Neurological and Sensory Disease Control Program, Division of Chronic Disease Programs, Public Health Service. This study was supported by a cooperative agreement between the Public Health Service and the University of North Carolina.