Hearing Loss — Types, Causes, Audiometry & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Hearing loss is the partial or complete inability to hear sound in one or both ears. It is classified by mechanism into conductive hearing loss (CHL — impaired sound transmission through the outer or middle ear), sensorineural hearing loss (SNHL — damage to the cochlea or auditory nerve — the most common type in adults), and mixed (both components). By degree: mild (26-40 dB), moderate (41-70 dB), severe (71-90 dB), and profound (above 90 dB). The World Health Organization estimates 1.5 billion people globally have some degree of hearing loss, with 430 million requiring rehabilitation. Presbycusis (age-related SNHL) is the most common cause in adults — affecting 30% of adults over 65 and 50% over 75. Untreated hearing loss is now identified as the largest modifiable risk factor for dementia, accounting for 9% of potentially preventable dementia cases (Lancet 2024 Commission).

Conductive hearing loss: wax impaction (cerumen — the most common correctable cause); otitis media with effusion (OME, 'glue ear' — most common cause of CHL in children, affecting 80% of children at some point before age 10); acute otitis media (AOM); otosclerosis (abnormal bone growth at the stapes footplate — progressive CHL in young adults, often hereditary); tympanic membrane perforation (trauma, infection, cholesteatoma). Sensorineural hearing loss: presbycusis (cumulative hair cell loss in the basal cochlea — progressive high-frequency hearing loss with ageing); noise-induced hearing loss (NIHL — second most common cause globally; from occupational or recreational noise exposure; irreversible hair cell damage); ototoxic medications (aminoglycosides, cisplatin, loop diuretics at high doses, quinine); Meniere's disease (endolymphatic hydrops — episodic SNHL, tinnitus, vertigo, and aural fullness); sudden sensorineural hearing loss (SSNHL — rapid onset over 72 hours, idiopathic in 90%; a medical emergency); meningitis and other infections; and congenital causes (CMV — most common cause of non-hereditary congenital SNHL; genetic mutations in GJB2/connexin 26 — most common cause of hereditary SNHL).

Difficulty hearing speech, particularly in background noise (cocktail party effect — difficulty separating speech from ambient noise is one of the earliest SNHL symptoms). Asking people to repeat themselves frequently; mishearing words; difficulty on the telephone; turning up the TV louder than others prefer; tinnitus (ringing, buzzing, or hissing in the ears — accompanies SNHL in many patients); aural fullness. Conductive hearing loss additionally causes: muffled hearing (like underwater sensation), better hearing of own voice (autophony in Eustachian tube dysfunction), and visible fluid behind the eardrum on otoscopy in OME. Sudden SNHL presents as acute unilateral deafness — often noticed on waking — and is a medical emergency. In children: speech and language developmental delay, inattentiveness, difficulty at school, and behavioural problems are common presentations of OME.

Pure tone audiometry (PTA): the gold standard — tests hearing thresholds at frequencies from 250 Hz to 8,000 Hz using both air conduction (headphones — tests entire auditory pathway) and bone conduction (vibrator behind the ear — bypasses outer and middle ear, testing cochlear/neural function). An air-bone gap greater than 10 dB confirms conductive hearing loss. Tympanometry: assesses middle ear pressure and tympanic membrane mobility — detects OME (flat type B tympanogram) and ossicular abnormalities. Speech audiometry: word recognition scores assess clarity of hearing with amplification — important for determining cochlear implant candidacy. Otoacoustic emissions (OAE) and auditory brainstem response (ABR/BERA): used for newborn hearing screening (NHS) and in patients unable to co-operate with PTA. MRI internal auditory meati: for asymmetric SNHL or tinnitus — excludes vestibular schwannoma (acoustic neuroma, occurring in 1 per 100,000 annually). Genetic testing: for bilateral congenital SNHL — GJB2 (connexin 26) mutation panel.

Conductive hearing loss: wax removal (ear syringing, microsuction, or Cerumol drops); grommet insertion (ventilation tube) for persistent OME with hearing loss in children after 3 months — reduces the hearing threshold by 15-20 dB; hearing aids for otosclerosis or perforation if surgery not desired; stapedectomy (otosclerosis) — replaces the fixed stapes with a prosthesis, restoring nearly normal hearing in 90% of patients; tympanoplasty for membrane perforation. Sensorineural hearing loss: hearing aids (for mild to moderate SNHL) — modern digital hearing aids with directional microphones, Bluetooth connectivity, and noise reduction; NHS provides hearing aids free in the UK. Cochlear implants: for severe-profound SNHL when hearing aids provide insufficient benefit — a surgically implanted electrode array stimulates the auditory nerve directly; most effective in post-lingually deafened adults and pre-lingually deafened children implanted early (ideally before 18 months). Bone-anchored hearing aids (BAHA) or bone conduction implants: for CHL when conventional aids are unsuitable. Sudden SNHL: oral corticosteroids (prednisolone 60 mg daily for 14 days) within 72 hours of onset — approximately 50-60% of patients recover partially or fully; intratympanic steroid injection as adjunct or salvage therapy. Tinnitus: cognitive behavioural therapy (CBT), hearing aids, and tinnitus retraining therapy.

Untreated hearing loss carries significant consequences across multiple domains of health and wellbeing. Cognitive decline and dementia: hearing loss is the single largest potentially modifiable risk factor for dementia — those with severe hearing loss have a 5-fold increased risk of dementia compared to those with normal hearing, and an estimated 8% of dementia cases might be preventable by treating hearing loss. Social isolation and depression are strongly associated with untreated hearing loss — difficulty communicating in social settings leads to withdrawal, loneliness, and clinical depression, which in turn accelerate cognitive decline. Childhood hearing loss causes impaired speech and language development, delayed acquisition of reading and writing, and academic underperformance — early hearing aid fitting or cochlear implantation in profoundly deaf children dramatically improves outcomes if provided in the first year of life. Falls risk is increased in those with hearing loss — from reduced spatial awareness and impaired balance processing in the auditory system. Tinnitus frequently co-occurs with sensorineural hearing loss as the auditory cortex compensates for reduced input with maladaptive neural changes. Loss of income and employment opportunities: hearing loss causes communication difficulties in the workplace, reducing employment rates and career progression. Wearing hearing aids when prescribed significantly reduces these downstream complications.

Noise protection is the most important preventable cause: wear hearing protection (ear plugs or ear defenders) in noisy work environments (noise levels above 85 dB — construction, factories, live music); limit exposure to recreational noise (concerts, headphone use — follow the 60/60 rule: maximum 60% volume for maximum 60 minutes). Avoid ototoxic medications when alternatives exist; if cisplatin chemotherapy is essential, regular audiometric monitoring detects hearing changes early allowing dose adjustment. Newborn hearing screening (NHS) detects congenital hearing loss within days of birth, enabling early intervention before speech and language development is compromised. Vaccinate children against meningococcal disease (Men ACWY, Men B), pneumococcus, measles, and mumps — major vaccine-preventable causes of acquired hearing loss. Treat otitis media promptly. Wearing hearing aids when prescribed significantly reduces the long-term risk of cognitive decline associated with untreated hearing loss.

Seek same-day urgent review for sudden hearing loss in one or both ears occurring over less than 72 hours — sudden sensorineural hearing loss is a medical emergency; early steroid treatment significantly improves outcomes. Attend urgently for: ear pain with fever (acute otitis media or mastoiditis); hearing loss with vertigo, tinnitus, and aural fullness (possible Meniere's disease); hearing loss following trauma; or discharge from the ear. Book a GP or audiology appointment for gradual hearing loss affecting daily communication, difficulty following conversations in group settings, frequently asking people to repeat, or concerns about a child's hearing or speech development. In children, any language delay or inattentiveness at school warrants audiological assessment. Adults over 55 should have hearing assessed every 5 years as part of healthy ageing, and fit hearing aids early — hearing aid use reduces dementia risk.