Causes of Hearing Loss & Deafness: Genetic, Age, Noise, Medical & More

Hearing loss (HL) is classified by type (conductive, sensorineural, mixed), severity (mild to profound), laterality (unilateral/bilateral), and onset (congenital/acquired). Major etiologies:

1. Genetic (50–60% congenital HL)

• Non-syndromic (GJB2/Connexin 26 most common) vs. syndromic (Usher, Waardenburg, Pendred).
• Inheritance: Autosomal recessive (80%), dominant, X-linked, mitochondrial.

2. Presbycusis (Age-Related)

Progressive bilateral high-frequency SNHL from hair cell/strial degeneration. Starts ~50s; affects ⅔ >70 yrs.

3. Noise-Induced HL

Occupational (construction, military), recreational (firearms, music, headphones). 4–6 kHz notch. Preventable (protection, volume limits).

4. Infections & Inflammatory

• Congenital: CMV, rubella, toxoplasmosis, syphilis, Zika.
• Acquired: Meningitis, mumps, measles, chronic otitis media, Ramsay Hunt.

5. Ototoxic Medications

• Aminoglycosides, platinum chemo, loop diuretics, high-dose salicylates, macrolides.
• Risk: Cumulative dose, renal impairment, age, noise co-exposure.

6. Structural/Traumatic

• Otosclerosis (stapes fixation → conductive HL).
• Temporal bone fracture, barotrauma, acoustic trauma.
• Cholesteatoma, tympanosclerosis.

7. Ménière's Disease

Endolymphatic hydrops → episodic vertigo, fluctuating HL, tinnitus, aural fullness.

8. Autoimmune Inner Ear Disease (AIED)

Rapidly progressive bilateral SNHL; steroid-responsive; associated with systemic autoimmunity.

Evaluation

Audiogram, tympanometry, OAEs, ABR, imaging (MRI/IAC), genetic testing, labs. ENT/Audiology referral for all unexplained HL.