A 52-year-old man presents with slowly progressive hearing loss in the right ear over 8 months, associated with ipsilateral tinnitus and mild unsteadiness. Pure tone audiometry shows an asymmetric sensorineural loss. There are no discrete vertigo attacks. Which investigation is most appropriate next?
- A Electrocochleography
- B Tympanometry with acoustic reflex decay
- C MRI of internal auditory canals with gadolinium contrast ✓
- D Bithermal caloric testing
Correct answer: C. MRI of internal auditory canals with gadolinium contrast
Explanation
Progressive asymmetric sensorineural hearing loss without episodic vertigo points to a retrocochlear lesion, classically vestibular schwannoma. Gadolinium-enhanced MRI of the internal auditory meatus is the gold standard and detects tumours as small as 2 mm. Electrocochleography and calorics assess cochlear and vestibular function in Meniere's disease and would be normal or non-specific here. Acoustic reflex decay supports retrocochlear pathology but cannot image or exclude a mass, so it does not answer the clinical question.
Reference: Dhingra's Diseases of Ear, Nose and Throat, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.