ABA ABA Hearing Conservation & Occupational Audiology 2 — Questions and Answers
Question 1: Which type of hearing protector generally provides the highest attenuation for workers exposed to very high-level impact noise?
- Single-flange earplugs
- Earmuffs alone
- Combined earmuffs and earplugs (Correct answer)
- Semi-insert canal caps
Correct answer: Combined earmuffs and earplugs
Combining earmuffs with earplugs (dual protection) provides the greatest attenuation, typically adding about 5–10 dB beyond the higher-rated device alone.
Question 2: The NIOSH recommended exposure limit (REL) for occupational noise is:
- 90 dBA TWA8
- 85 dBA TWA8 (Correct answer)
- 80 dBA TWA8
- 75 dBA TWA8
Correct answer: 85 dBA TWA8
NIOSH recommends an 85 dBA TWA8 REL with a 3 dB exchange rate, which is more protective than OSHA's 90 dBA PEL.
Question 3: Temporary threshold shift (TTS) after noise exposure typically shows maximum recovery within:
- 1–2 hours
- 16–48 hours (Correct answer)
- 1 week
- 1 month
Correct answer: 16–48 hours
TTS typically resolves within 16–48 hours after cessation of noise exposure; failure to fully recover suggests permanent threshold shift (PTS).
Question 4: Which ototoxic class of antibiotics is most associated with occupational synergistic hearing loss when combined with noise exposure?
- Penicillins
- Macrolides
- Aminoglycosides (Correct answer)
- Fluoroquinolones
Correct answer: Aminoglycosides
Aminoglycosides (e.g., gentamicin, tobramycin) are cochleotoxic and their combined effect with noise exposure can produce greater hearing loss than either factor alone.
Question 5: In a hearing conservation program, audiometric monitoring must be repeated at minimum on what schedule for workers at or above the OSHA action level?
- Every 6 months
- Annually (Correct answer)
- Every 2 years
- Every 5 years
Correct answer: Annually
OSHA requires annual audiograms for all employees exposed at or above the 85 dBA TWA8 action level to monitor for progressive threshold shifts.
Question 6: Which engineering control is the most preferred approach in the hierarchy of noise controls?
- Hearing protection devices
- Administrative controls such as job rotation
- Substitution of a quieter process or equipment (Correct answer)
- Enclosure of the worker
Correct answer: Substitution of a quieter process or equipment
The hierarchy of noise controls prioritizes elimination and substitution at the top, making substitution of quieter machinery the most preferred engineering approach.
ABA ABA Hearing Conservation & Occupational Audiology 2
Which type of hearing protector generally provides the highest attenuation for workers exposed to very high-level impact noise?