Key Facts

Hearing loss is one of the most common disabilities worldwide and the third most common chronic health condition in older adults. It significantly impacts communication, social interaction, mental health, and quality of life. Early identification and management are essential.

Epidemiology

• 11 million people affected in the UK (1 in 6)
• Prevalence increases steeply with age: 40% of >50s, 70% of >70s
• Congenital hearing loss: 1-2 per 1,000 newborns
• Noise-induced hearing loss affects 17% of adults
• WHO estimates 466 million people worldwide have disabling hearing loss

Aetiology

• Conductive: cerumen impaction (most common treatable cause), otitis media with effusion, chronic otitis media, otosclerosis, TM perforation, cholesteatoma, Eustachian tube dysfunction
• Sensorineural: presbycusis (most common overall), noise-induced, ototoxic drugs (aminoglycosides, cisplatin, loop diuretics), Ménière disease, vestibular schwannoma, congenital (genetic, TORCH infections), sudden SNHL (idiopathic/viral)
• Mixed: combination, e.g. chronic otitis media with cochlear damage

Pathophysiology

• Conductive: mechanical impedance to sound transmission through external or middle ear
• Sensorineural: damage to cochlear hair cells (especially outer hair cells), stria vascularis, or cochlear nerve
• Presbycusis: progressive loss of hair cells starting at basal turn (high-frequency loss first)
• Noise-induced: mechanical damage to stereocilia from excessive sound energy
• Ototoxicity: direct damage to hair cells (aminoglycosides) or stria vascularis (loop diuretics)

Conductive Hearing Loss

• Difficulty hearing, often aware of reduced volume
• May hear better in noisy environments (paracusis of Willis, classically otosclerosis)
• History of ear infections, discharge, trauma, or surgery
• Family history (otosclerosis)

Sensorineural Hearing Loss

• Difficulty understanding speech, especially in background noise
• High-frequency loss: difficulty hearing consonants, women's/children's voices
• Tinnitus (common association)
• Vertigo (if vestibular involvement — Ménière, vestibular schwannoma)
• Gradual onset (presbycusis, noise-induced) or sudden (viral, vascular)

Red Flags — Urgent Assessment Required

• Sudden sensorineural hearing loss (<72 hours) — ENT emergency
• Unilateral hearing loss — exclude vestibular schwannoma (MRI)
• Asymmetric hearing loss — investigate for retrocochlear pathology
• Pulsatile tinnitus — vascular cause (glomus tumour, AVF)
• Associated facial nerve palsy
• Hearing loss with vertigo and progressive symptoms

Bedside

• Otoscopy: cerumen, TM abnormalities, middle ear pathology
• Tuning fork tests (512Hz):
  • Rinne test: compares air conduction (AC) and bone conduction (BC)
    • Normal/SNHL: AC > BC (Rinne positive)
    • CHL: BC > AC (Rinne negative)
  • Weber test: central placement
    • CHL: lateralises to affected ear
    • SNHL: lateralises to unaffected (better) ear
• Whispered voice test: simple screening (sensitivity ~90%)

Bloods

• Not routinely required
• Consider: FBC, ESR, TFTs, glucose, syphilis serology, autoimmune screen in unexplained SNHL

Imaging

• MRI internal auditory meatus (IAM) with gadolinium: gold standard for suspected vestibular schwannoma (unilateral/asymmetric SNHL)
• CT temporal bones: for conductive hearing loss assessment, cholesteatoma, otosclerosis, trauma

Special Tests

• Pure tone audiometry (PTA): gold standard hearing assessment
  • Air and bone conduction thresholds at 250Hz-8kHz
  • Air-bone gap >10dB indicates conductive component
• Tympanometry: middle ear compliance (types A, B, C, As, Ad)
• Speech audiometry: speech discrimination testing
• Otoacoustic emissions (OAE): tests outer hair cell function
• Auditory brainstem response (ABR): threshold estimation, retrocochlear assessment
• Newborn hearing screening: AOAE and ABR

Non-pharmacological

• Cerumen removal: microsuction, ear irrigation, olive oil drops for softening
• Hearing aids: first-line for mild-moderate SNHL (NICE NG98)
  • Behind-the-ear (BTE) most common NHS provision
  • Digital hearing aids with directional microphones
• Assistive listening devices: personal amplifiers, loop systems, subtitles
• Communication strategies: face the speaker, reduce background noise, lip reading
• Noise protection: ear defenders, custom-moulded plugs for occupational/recreational exposure

Pharmacological

• Sudden SNHL: oral prednisolone 1mg/kg (max 60mg) OD for 7-14 days, taper over 1-2 weeks
  • Intratympanic dexamethasone injection as salvage therapy if oral steroids fail
• Ménière disease: betahistine 16mg TDS (symptomatic relief)
• Ototoxic drug review: discontinue or substitute where possible

Surgical

• Grommets: for persistent OME with hearing loss in children (NICE NG233)
• Stapedectomy/stapedotomy: for otosclerosis (success rate >90% closure of air-bone gap)
• Tympanoplasty/ossiculoplasty: for chronic ear disease with conductive loss
• Cochlear implants: for severe-profound bilateral SNHL (NICE TA566)
  • Criteria: ≥80dB HL at 2 and 4kHz, inadequate benefit from hearing aids
• Bone-anchored hearing aid (BAHA): for single-sided deafness, conductive/mixed hearing loss not suitable for conventional aids

Referral Criteria

• Emergency ENT: sudden SNHL (<72 hours)
• Urgent ENT (2 weeks): unilateral/asymmetric SNHL (vestibular schwannoma exclusion)
• Routine ENT: conductive hearing loss, persistent hearing difficulty, cholesteatoma
• Audiology: all patients with hearing difficulty for PTA and hearing aid assessment

• Presbycusis: progressive; hearing aids provide significant benefit and improve quality of life
• Sudden SNHL: 30-65% spontaneous partial recovery; better with early steroid treatment
• Otosclerosis: excellent surgical prognosis; stapedectomy success rate >90%
• Noise-induced: preventable; once established, hearing loss is permanent
• Cochlear implants: significant speech perception improvement in >80% of adults and >90% of children
• Untreated hearing loss is associated with social isolation, depression, cognitive decline, and increased dementia risk (Lancet Commission 2020: hearing loss is the single largest modifiable risk factor for dementia)

Classification of Hearing Loss Severity (WHO/BSA)

Common Audiometric Patterns

Key Landmark: Lancet Commission on Dementia (2020)