On pure tone audiometry, a patient shows an air-bone gap (bone conduction normal, air conduction reduced) with a characteristic 'V-shaped' dip at 2000 Hz. This pattern is most associated with:
- A Carhart's notch in otosclerosis ✓
- B Noise-induced hearing loss
- C Otosclerosis
- D Presbycusis
Correct answer: A. Carhart's notch in otosclerosis
Explanation
Carhart's notch is a characteristic audiometric finding in otosclerosis: a mechanical artifact causing apparent bone conduction depression of approximately 5 dB at 500 Hz, 10 dB at 1000 Hz, 15 dB at 2000 Hz, and 5 dB at 4000 Hz, creating a notch-like dip in bone conduction at 2000 Hz. This is NOT true cochlear sensorineural loss — it represents the mechanical inertial effect of the fixed stapes on bone-conducted vibration. After successful stapedectomy, the Carhart notch disappears. Noise-induced hearing loss shows a notch at 4000 Hz in air conduction.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.