Hearing Loss — Causes, Symptoms, Diagnosis & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Hearing loss is the partial or complete inability to hear sounds in one or both ears. It affects approximately 1.5 billion people worldwide, making it the most common sensory disability, with 430 million people having disabling hearing loss requiring rehabilitation. Hearing loss is classified by type (sensorineural, conductive, or mixed), severity (mild, moderate, severe, profound), and onset (congenital or acquired). Age-related hearing loss (presbycusis) is the leading cause in adults. Untreated hearing loss causes significant communication difficulties, social isolation, cognitive decline, and is now recognized as a major modifiable risk factor for dementia. The 2020 Lancet Commission on dementia identified hearing loss as the single largest potentially modifiable risk factor for dementia, responsible for approximately 8% of cases — treating hearing loss may delay or reduce dementia risk. Congenital hearing loss, if undetected at birth, leads to critical language development deficits — the sensitive period for language acquisition is the first 3 years of life, making universal newborn hearing screening of utmost importance. Tinnitus (ringing in the ears) frequently accompanies sensorineural hearing loss and adds a significant additional burden.

Sensorineural hearing loss (SNHL) results from damage to the cochlear hair cells or auditory nerve — causes include aging (presbycusis), noise exposure (acoustic trauma), ototoxic medications (aminoglycosides, cisplatin, loop diuretics), Meniere's disease, viral infections (mumps, measles, meningitis), autoimmune inner ear disease, and genetic mutations (GJB2/connexin 26 most common congenital SNHL cause). Conductive hearing loss results from mechanical blockage of sound transmission — causes include otitis media with effusion (glue ear), cerumen impaction, otosclerosis, tympanic membrane perforation, and ossicular chain disruption from trauma. Noise-induced hearing loss from occupational or recreational exposure is a major preventable cause. Presbycusis (age-related hearing loss) begins in the high frequencies (above 2000 Hz) and progressively involves speech frequencies — it affects 50% of those over 75 and is the cumulative result of decades of noise exposure, genetic factors, vascular disease, and cochlear hair cell senescence. Ménière's disease — caused by endolymphatic hydrops (excess fluid in the inner ear) — causes episodic sensorineural hearing loss, tinnitus, aural fullness, and rotational vertigo lasting 20 minutes to 24 hours, with fluctuating hearing loss that may become permanent over time.

Symptoms include difficulty understanding speech (especially in noisy environments), asking others to repeat themselves, turning up the television volume, difficulty hearing on the telephone, tinnitus (ringing, buzzing, or humming in the ears), and social withdrawal from conversations and group activities. In children, hearing loss causes delayed speech and language development, learning difficulties, and behavioral problems. Sudden sensorineural hearing loss (SSNHL) — loss occurring over 72 hours — is an otological emergency requiring urgent steroid treatment. Vertigo accompanying hearing loss suggests Meniere's disease or labyrinthitis. Hyperacusis — abnormal sensitivity to everyday sounds — frequently coexists with sensorineural hearing loss and tinnitus, particularly after acoustic trauma or in vestibular disorders. Sudden sensorineural hearing loss (SSNHL) — defined as loss of 30 dB or more at three consecutive frequencies within 72 hours — is an otological emergency where immediate high-dose oral prednisolone (1 mg/kg/day up to 60 mg) significantly improves recovery rates compared to delayed treatment.

Pure tone audiometry measures hearing thresholds across frequencies (250 Hz to 8000 Hz) and quantifies severity: normal (0–25 dB), mild (26–40 dB), moderate (41–60 dB), severe (61–80 dB), and profound (above 81 dB). Air-bone gap confirms conductive component. Speech audiometry assesses word recognition ability. Tympanometry measures middle ear pressure and eardrum mobility (identifies otitis media with effusion, perforation, or otosclerosis). Auditory brainstem response (ABR) testing evaluates auditory nerve function and is the standard for newborn hearing screening and diagnosis in infants. MRI of the internal auditory canals is performed if acoustic neuroma (vestibular schwannoma) is suspected. Speech audiometry using phonetically balanced word lists measures word recognition scores (WRS) — important for hearing aid candidacy and cochlear implant eligibility. Acoustic reflex testing using a stapedial reflex arc assesses middle ear pressure and retrocochlear pathology. Electrocochleography (ECoG) measures the summating potential to action potential ratio and is used to diagnose Ménière's disease and endolymphatic hydrops. Vestibular evoked myogenic potentials (VEMPs) assess saccular and otolith function.

Conductive hearing loss from cerumen impaction is treated by ear irrigation or microsuction. Otitis media with effusion resolves spontaneously in 90% within 3 months; persistent cases requiring hearing rehabilitation use grommets (ventilation tubes). Otosclerosis is treated by stapedectomy surgery. Sensorineural hearing loss is managed with digital hearing aids fitted by an audiologist for mild-to-severe loss — modern devices include Bluetooth connectivity and artificial intelligence sound processing. Cochlear implants are indicated for severe-to-profound SNHL when hearing aids provide insufficient benefit; they bypass the cochlea and directly stimulate the auditory nerve with remarkable speech comprehension outcomes. Bone-anchored hearing aids (BAHA) are used for single-sided deafness and conductive loss. Intratympanic steroid injection (dexamethasone 4 mg/mL, 3–4 injections over 2 weeks) is used as first-line treatment for SSNHL or as salvage therapy after systemic steroids fail — delivers high local drug concentration with minimal systemic side effects. Hearing loop systems (telecoil technology in hearing aids) and assistive listening devices are adjuncts for specific communication environments. Auditory rehabilitation programs combining hearing aids with audiologist-led communication training improve outcomes beyond technology alone.

Untreated hearing loss causes progressive social isolation, communication difficulties, and significant psychological impact including depression and anxiety. A landmark 2020 Lancet Commission on dementia identified hearing loss as the single largest potentially modifiable risk factor for dementia, responsible for approximately 8% of dementia cases. Treating hearing loss with hearing aids is associated with reduced cognitive decline in observational studies. In children, untreated hearing loss causes permanent deficits in speech, language, and academic development. Tinnitus complicating hearing loss causes sleep disturbance and significant distress in a proportion of patients.

Limit noise exposure: use hearing protection (earplugs or noise-canceling earmuffs) in occupational settings above 85 dB and recreational settings (concerts, power tools, motorcycles). Follow the 60/60 rule for headphones — no more than 60% volume for no more than 60 minutes at a stretch. WHO's Make Listening Safe campaign recommends safe listening features in smartphones. Get hearing tested promptly after any occupational noise exposure or ototoxic medication exposure. Universal newborn hearing screening identifies congenital hearing loss for early intervention. Annual audiometry for those over 65 or with known risk factors ensures timely hearing aid fitting before social isolation and cognitive decline progress.

Seek urgent same-day ENT assessment for sudden sensorineural hearing loss — any noticeable hearing loss developing within 72 hours in one or both ears is a medical emergency; oral high-dose prednisolone (or intratympanic steroid injection) started within days of onset significantly improves the chance of recovery. Do not wait and see with sudden hearing loss. See your GP for: gradual hearing loss, difficulty following conversations especially in background noise, turning up the TV volume, or frequently asking people to repeat themselves — an audiometry referral can confirm the degree and type of loss. Any new unilateral (one-sided) tinnitus, or tinnitus associated with balance problems or hearing loss, requires ENT assessment and MRI of the internal auditory canals to exclude vestibular schwannoma (acoustic neuroma). Report any hearing loss in a child at any age — delayed speech and language development, not responding to their name, or not startling to loud sounds are indications for urgent paediatric audiology referral. Occupational noise exposure above 85 dB warrants annual audiometry surveillance.