Noise-Induced Hearing Loss MCQ — NEET PG Practice Question | NEETPGAI
Noise-Induced Hearing Loss
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ear ENT
A 52-year-old male construction worker presents with progressive bilateral hearing loss and tinnitus. He has worked on noisy construction sites for 25 years without consistent hearing protection. Pure-tone audiometry is performed, and the audiogram shows the pattern marked **B** in the diagram. Which of the following best explains why this audiometric pattern is characteristic of noise-induced hearing loss and distinguishes it from other causes of sensorineural hearing loss?
A. The 4-kHz notch reflects selective damage to outer hair cells at the basal turn of the cochlea, with recovery at 8 kHz due to relative sparing of the apical turn
B. The low-frequency loss with normal high-frequency thresholds reflects endolymphatic hydrops and mechanical dysfunction of the cochlear duct
C. The downsloping high-frequency loss at all frequencies reflects age-related degeneration of the stria vascularis and cochlear neurons
D. The bilateral symmetric loss at 2 and 3 kHz reflects ototoxic injury from concurrent exposure to industrial solvents and aminoglycosides
Explanation
Why option 1 is right
The characteristic audiometric finding in noise-induced hearing loss is a notch at 3000–6000 Hz (typically deepest at 4 kHz) with recovery at 8 kHz. This pattern reflects selective mechanical and metabolic injury to outer hair cells at the basal turn of the cochlea, where 4-kHz frequencies are preferentially transduced. The recovery at 8 kHz distinguishes NIHL from presbycusis and is a hallmark diagnostic feature. According to OSHA 29 CFR 1910.95 and NIOSH criteria, this notch pattern is the gold standard for identifying occupational noise exposure as the cause of sensorineural hearing loss.
Why each distractor is wrong
Option 2 (Presbycusis): Presbycusis causes a downsloping audiogram that continues to worsen at 8 kHz and beyond, without the characteristic recovery at 8 kHz seen in NIHL. This is the key distinction between the two most common causes of adult SNHL.
Option 3 (Menière's disease): Menière's disease typically presents with low-frequency hearing loss (affecting 250–2000 Hz), not the high-frequency 4-kHz notch pattern. It is associated with endolymphatic hydrops and episodic vertigo, not chronic occupational noise exposure.
Option 4 (Ototoxic injury): While ototoxic drugs (aminoglycosides, cisplatin) and solvents can cause SNHL, they typically produce a more diffuse high-frequency loss without the distinctive 4-kHz notch with 8-kHz recovery that characterizes NIHL.
High-YieldNEET PG
NIHL = 4-kHz notch with recovery at 8 kHz; presbycusis = continuous downslope; Menière's = low-frequency loss. The notch is pathognomonic for noise exposure.
OSHA 29 CFR 1910.95; NIOSH Criteria Document 1998
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