ABA ABA Hearing Conservation & Occupational Audiology 1 — Questions and Answers
Question 1: According to OSHA's Hearing Conservation Amendment (29 CFR 1910.95), the action level at which a hearing conservation program must be implemented is:
- 80 dBA TWA8
- 85 dBA TWA8 (Correct answer)
- 90 dBA TWA8
- 100 dBA TWA8
Correct answer: 85 dBA TWA8
OSHA requires employers to implement a hearing conservation program when workers are exposed to a time-weighted average of 85 dBA or more over an 8-hour workday.
Question 2: OSHA's Permissible Exposure Limit (PEL) for occupational noise is based on which exchange rate?
- 3 dB exchange rate
- 4 dB exchange rate
- 5 dB exchange rate (Correct answer)
- 6 dB exchange rate
Correct answer: 5 dB exchange rate
OSHA uses a 5 dB exchange rate, meaning the allowable exposure time halves for every 5 dB increase in noise level above 90 dBA.
Question 3: A standard threshold shift (STS) under OSHA's hearing conservation standard is defined as a change in hearing threshold averaging how many dB in either ear at 2000, 3000, and 4000 Hz?
- 10 dB
- 15 dB (Correct answer)
- 20 dB
- 25 dB
Correct answer: 15 dB
OSHA defines an STS as an average shift of 10 dB or more at 2000, 3000, and 4000 Hz in either ear compared to the baseline audiogram.
Question 4: Which audiometric pattern is most characteristic of noise-induced hearing loss (NIHL)?
- Flat sensorineural hearing loss
- Low-frequency sensorineural hearing loss
- Notch at 4000 Hz with recovery at 8000 Hz (Correct answer)
- Conductive hearing loss at all frequencies
Correct answer: Notch at 4000 Hz with recovery at 8000 Hz
NIHL typically presents as a sensorineural notch at 4000 Hz (sometimes 3000–6000 Hz) with relative recovery at 8000 Hz, reflecting the cochlea's frequency-place map and mechanical resonance.
Question 5: The Noise Reduction Rating (NRR) is used to estimate hearing protector performance. According to OSHA's method, the real-world noise attenuation is calculated by deducting 7 from the NRR and then:
- Subtracting the result directly from the C-weighted noise level
- Dividing the result by 2 when using A-weighted measurements (Correct answer)
- Multiplying the result by 0.75
- Subtracting the result from the A-weighted level without further adjustment
Correct answer: Dividing the result by 2 when using A-weighted measurements
When using A-weighted sound levels, OSHA's method requires dividing (NRR − 7) by 2 to account for real-world variability in hearing protector performance.
Question 6: A baseline audiogram under OSHA's hearing conservation standard must be conducted within how many months of an employee's first noise exposure at or above the action level?
- 1 month
- 3 months
- 6 months (Correct answer)
- 12 months
Correct answer: 6 months
OSHA requires the baseline audiogram to be obtained within 6 months of first exposure, or within 1 year if mobile test vans are used.
ABA ABA Hearing Conservation & Occupational Audiology 1
According to OSHA's Hearing Conservation Amendment (29 CFR 1910.95), the action level at which a hearing conservation program must be implemented is: