Audiogram

Audiogram
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Name	Audiogram
Classification	Diagnostic chart
Invented	Early 20th century
Inventor	Harvey Fletcher
Used for	Hearing threshold measurement

Audiogram

An audiogram is a graphical representation of auditory threshold measurements used in audiology, otology, and hearing science. It summarizes hearing sensitivity across frequencies and is employed by professionals associated with World Health Organization, American Speech-Language-Hearing Association, National Institutes of Health, Mayo Clinic, and Cleveland Clinic for diagnosis, management, and research. Clinicians from institutions such as Johns Hopkins Hospital, Massachusetts General Hospital, and Royal National Throat, Nose and Ear Hospital use audiograms alongside tools from manufacturers like Siemens and GN ReSound.

Overview and Purpose

An audiogram displays the softest sounds a person can hear at specified frequencies and is central to work by specialists in otolaryngology, audiology, and allied teams at centers like UCLA Health, Karolinska Institutet, and Great Ormond Street Hospital. It guides decision-making by authorities such as American Academy of Otolaryngology–Head and Neck Surgery and international programs coordinated by United Nations agencies. Occupational programs run by entities like Occupational Safety and Health Administration and military health services in United States Department of Defense use audiograms to document noise-induced threshold shift and align with standards from International Organization for Standardization.

Types and Formats

Audiograms are presented in multiple formats used by clinics like Johns Hopkins Hospital, research groups at Massachusetts Institute of Technology, and manufacturers including Oticon and Phonak. Common formats include pure-tone audiograms, speech audiograms, and high-frequency audiograms; formats adhere to conventions referenced by American National Standards Institute and British Society of Audiology. Specialized visualizations appear in publications from Nature, The Lancet, and New England Journal of Medicine for epidemiologic studies by teams at Harvard T.H. Chan School of Public Health and London School of Hygiene & Tropical Medicine.

Testing Procedures and Interpretation

Testing is typically performed by audiologists trained at programs associated with University of Iowa, University of Michigan, or University College London using calibrated equipment from firms like Interacoustics and Grason-Stadler. Procedures include air-conduction and bone-conduction testing, speech recognition thresholds, and masking protocols following guidance from American Speech-Language-Hearing Association and standards from International Organization for Standardization. Interpretation relates findings to diagnostic entities managed by specialists at Cleveland Clinic and Mount Sinai Health System, and may trigger referrals to surgeons at Johns Hopkins Hospital for cochlear implant evaluation or to centers performing tympanoplasty like Guy's and St Thomas' NHS Foundation Trust.

Clinical Applications and Uses

Audiograms inform clinical pathways in pediatrics at institutions such as Children's Hospital of Philadelphia and neonatal screening programs promoted by Centers for Disease Control and Prevention. They support habilitation and rehabilitation decisions involving devices from Cochlear Limited and protocols developed by World Health Organization. In occupational medicine, employers coordinate with agencies like National Institute for Occupational Safety and Health for hearing conservation; in veteran care, organizations such as Department of Veterans Affairs rely on audiograms for claims and treatment planning. Research initiatives at Stanford University and University of Cambridge use audiometric data in studies of presbycusis and ototoxicity linked to medications approved by Food and Drug Administration.

Limitations and Sources of Error

Audiograms are subject to variability from testing environments, equipment calibration by manufacturers like Grason-Stadler, and patient factors addressed in training at University of Washington. Errors may stem from improper masking procedures, middle-ear pathology identified by tympanometry from devices by Interacoustics, or cross-hearing leading to misinterpretation in medicolegal contexts involving American Bar Association standards. Epidemiologic studies at Johns Hopkins Bloomberg School of Public Health highlight limitations for population screening, and consensus statements from bodies like World Health Organization caution about relying solely on audiograms without corroborating imaging from Magnetic Resonance Imaging or computed tomography performed at centers such as Royal Infirmary of Edinburgh.

History and Development

Foundational work in auditory measurement involved researchers at Bell Laboratories and physicists like Harvey Fletcher; developments paralleled institutions including Carnegie Institution for Science and Bell Telephone Laboratories. The modern audiogram evolved through contributions from clinicians at Massachusetts Eye and Ear Infirmary and standards established by American National Standards Institute in the mid-20th century. Technological advances in hearing assessment, accelerated by companies like Siemens and academic groups at Massachusetts Institute of Technology, enabled portable audiometers and automated screening used today in programs by United Nations Children's Fund and national health services such as National Health Service (England).

Category:Medical tests