During pure tone audiometry of a patient with noise-induced hearing loss, a characteristic dip is found on the audiogram. At which frequency is this notch typically seen?
- A 250 Hz
- B 4000 Hz ✓
- C 1000 Hz
- D 8000 Hz
Correct answer: B. 4000 Hz
Explanation
Noise-induced sensorineural hearing loss characteristically produces a 'notch' on audiometry at 4000 Hz (C5 dip), corresponding to the basal turn of the cochlea which is most vulnerable to intense sound exposure. This area receives maximum mechanical stress due to the resonance properties of the external auditory canal and middle ear. Early stages spare speech frequencies (500-2000 Hz).
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.