to refer to the result of a pure tone audiometry hearing test. Hearing assessment Apart from testing hearing, part of the function of audiometry is in assessing or evaluating hearing from the test results. The most commonly used assessment of hearing is the determination of the threshold of audibility, i.e. the level of sound required to be just audible. This level can vary for an individual over a range of up to 5 decibels from day to day and from determination to determination, but it provides an additional and useful tool in monitoring the potential ill effects of exposure to noise. Hearing loss may be unilateral or bilateral, and bilateral hearing loss may not be symmetrical. The most common types of hearing loss, due to age and noise exposure, are usually bilateral and symmetrical. In addition to the traditional audiometry, hearing assessment can be performed using a standard set of frequencies (audiogram) with mobile applications to detect possible hearing impairments. Hearing loss classification The primary focus of audiometry is assessment of hearing status and hearing loss, including extent, type and configuration. There are four defined degrees of hearing loss: mild, moderate, severe and profound. Hearing loss may be divided into four types: conductive hearing loss, sensorineural hearing loss, central auditory processing disorders, and mixed types. Hearing loss may be unilateral or bilateral, of sudden onset or progressive, and temporary or permanent. Hearing loss may be caused by a number of factors including heredity, congenital conditions, age-related (presbycusis) and acquired factors like noise-induced hearing loss, ototoxic chemicals and drugs, infections, and physical trauma. Clinical practice Audiometric testing may be performed by a general practitioner medical doctor, an otolaryngologist (a specialized MD also called an ENT), a CCC-A (Certificate of Clinical Competence in Audiology) audiologist, a certified school audiometrist (a practitioner analogous to an optometrist who tests eyes), and sometimes other trained practitioners. Practitioners are certified by American Board of Audiology (ABA). Practitioners are licensed by various state boards regulating workplace health & safety, occupational professions, or ... Schools Occupational testing Noise-induced hearing loss Workplace and environmental noise is the most prevalent cause of hearing loss in the United States and elsewhere. Research Computer modeling of patterns of hearing deficit 3D longitudinal profiles of hearing loss including age axis (presbycusis study) See also Hearing test American Academy of Audiology International Society of Audiology Weber test Rinne Test Visual reinforcement audiometry References Ear