Audiology is the healthcare and scientific discipline concerned with hearing, balance and related communication functions, including assessment, diagnosis, rehabilitation and prevention of hearing disorders. Audiologists investigate how sound is transmitted through the ear and processed by the auditory system, from the external and middle ear through the cochlea, auditory nerve and central pathways. Their work includes hearing assessment, hearing-aid management, communication rehabilitation, tinnitus-related care and, in appropriate specialist services, vestibular assessment. Audiology therefore combines acoustics, anatomy, physiology, neuroscience, technology and clinical rehabilitation rather than being limited to fitting hearing aids.
Hearing loss can be classified in several ways. Conductive hearing loss arises when sound transmission through the external or middle ear is impaired, sensorineural hearing loss involves the cochlea or neural auditory pathways, and mixed hearing loss contains both components. The distinction is clinically important because causes, treatment options and prognosis differ. Conductive loss can result from conditions such as earwax obstruction, middle-ear fluid or ossicular abnormalities, whereas sensorineural loss can be associated with ageing, noise exposure, ototoxic medication, genetic factors and various diseases. Hearing loss can also be unilateral or bilateral, stable or progressive, and mild through profound in severity.
Audiological assessment uses multiple tests because no single measurement describes every aspect of hearing. Pure-tone audiometry determines hearing sensitivity to selected frequencies, while speech audiometry evaluates aspects of speech detection or understanding. Tympanometry examines middle-ear mechanics and can help identify abnormalities involving pressure or mobility of the tympanic membrane and middle-ear system. Otoacoustic emissions provide information related to cochlear outer-hair-cell function and are widely used in particular screening contexts, especially in newborn hearing programmes. Auditory brainstem response testing measures electrical responses associated with auditory neural pathways and can be valuable when conventional behavioural testing is difficult or when specific neurological information is required.
Hearing aids are electronic devices designed to amplify and process sound for people with hearing impairment. Modern digital hearing aids can provide frequency-specific amplification, directional microphone processing, feedback management, noise-reduction algorithms and connectivity features, although their effectiveness depends on the individual's hearing profile, communication environment, fitting and adaptation. Hearing aids do not restore normal hearing in the same way that corrective lenses can compensate for many refractive errors; they modify available acoustic information and cannot completely reproduce the function of a healthy auditory system. Audiological rehabilitation consequently includes counselling, realistic expectations, device programming, maintenance, communication strategies and follow-up rather than merely supplying hardware.
Cochlear implants represent a different form of hearing technology. A cochlear implant bypasses damaged sensory structures in the cochlea by converting sound into electrical stimulation delivered to the auditory nerve through an implanted electrode array. It is intended for selected people with sufficiently severe sensorineural hearing loss who meet clinical criteria and are likely to benefit from electrical auditory stimulation. Outcomes vary with factors including duration of deafness, age at implantation, auditory nerve function, language experience, rehabilitation and individual biological differences. Cochlear implants do not simply amplify sound, and successful use requires adaptation to the electrical representation of auditory information, often accompanied by structured rehabilitation.
Audiology also encompasses tinnitus and hyperacusis. Tinnitus is the perception of sound without a corresponding external acoustic source and can occur with or without measurable hearing loss. It may be associated with hearing impairment, noise exposure, ear disorders, medication or other factors, although its precise mechanisms can involve complex interactions between auditory and central nervous systems. Hyperacusis involves reduced tolerance to ordinary sounds, but it should be distinguished from simple dislike of loud noise. Management depends on the presentation and may involve hearing assessment, education, sound-based strategies, psychological approaches and treatment of relevant underlying conditions. Persistent unilateral symptoms or symptoms accompanied by other concerning findings may require medical investigation.
Balance is related to audiology because the inner ear contains both auditory and vestibular sensory organs. Specialist audiologists may perform vestibular investigations such as videonystagmography, video head impulse testing, vestibular evoked myogenic potentials and other tests depending on service configuration and training. These assessments examine different components of the vestibular system and help distinguish patterns of dysfunction. Vertigo is a symptom rather than a diagnosis, and vestibular disorders can arise from the inner ear, neurological system or other causes. Audiological vestibular practice therefore often involves collaboration with ear, nose and throat specialists, neurologists, physiotherapists and other professionals.
Hearing health has major effects on communication, education, employment and social participation. Childhood hearing impairment can affect speech and language development when it is not identified and appropriately managed, which is why newborn and childhood hearing screening programmes are important. In older adults, hearing loss can make conversation difficult, particularly in background noise, and may contribute to communication withdrawal and reduced participation. Audiology increasingly emphasises communication goals rather than hearing thresholds alone. Prevention also matters: reducing excessive occupational, recreational and environmental noise exposure can reduce the risk of noise-induced hearing damage. Audiology consequently combines measurement, technology, rehabilitation and prevention to address both auditory impairment and its functional consequences.
