CAOHC EXAMS SCRIPT 2026/2027 QUESTIONS AND
SOLUTIONS RATED A+
✔✔Sound pressure level (SPL) versus hearing level (HL) - ✔✔SPL describes noise
measurements taken with a sound level meter or dosimeter; HL describes threshold
levels obtained with an audiometer; 0 dB HL is not equal to 0 dB SPL
✔✔Noise Dosimeter - ✔✔A sound measurement device used to record the amount of
sound exposure over an extended period of
time (usually a work day)
Personal vs. Area
✔✔Sound level meter - ✔✔Uses a microphone to sense pressure variations in sound
waves; the meter converts those pressures directly into decibels; provides a noise
measurement that is a snapshot in time.
✔✔Time Weighted Average (TWA) - ✔✔An evaluation of exposures that is time-
weighted over an established period. It allow the exposure levels to be averaged
generally over an eight-hour time period.
✔✔OSHA exchange rate - ✔✔5 dB; for every 5 dB you go over the PEL of 90dBA TWA
you half the allowable time of exposure
✔✔OSHA Action Level for noise - ✔✔85dBA TWA
✔✔Sound Level Meter A-weighted Scale - ✔✔OSHA requires this scale as it resembles
how the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz)
✔✔Human Frequency Response at Birth - ✔✔20 Hz to 20,000 Hz (20 kHz)
✔✔Human speech frequency range - ✔✔250 Hz to 4000 Hz
✔✔Elements of a Hearing Conservation Program - ✔✔Noise hazard assessment;
engineering/administrative controls; annual hearing monitoring; annual
training/education; hearing protection; recordkeeping
✔✔OSHA Noise Amendment - ✔✔29 CFR 1910.95
✔✔Hughson-Westlake Procedure - ✔✔Common procedure for obtaining threshold; the
audiologist decreases stimulus intensity by 10 dB with a (+) response and increases by
5 dB with a (-) response
✔✔Hearing threshold level - ✔✔Lowest intensity level responded to at least 50% of the
time
, ✔✔Excessive noise levels will impact these test frequencies during a hearing exam -
✔✔Low frequencies e.g. 500 Hz
✔✔First frequency always tested on an occupational hearing exam - ✔✔1000 Hz
✔✔1000 Hz retest - ✔✔Done as a validity check on first ear tested; thresholds should
be within 5dB or should reinstruct patient and start test over
✔✔Presbycusis - ✔✔A gradual loss of sensorineural hearing that occurs as the body
ages
✔✔Professional Supervisor In a HCP - ✔✔Responsible for oversight of Audiometric
testing; reviews problem audiograms; must be an audiologist or physician
✔✔Elements of a Hearing Conservation Program - ✔✔Mandatory and includes:
exposure monitoring, audiometric testing, hearing protection, employee training, record
keeping, and program evaluation
✔✔Noise Controls - ✔✔At the source (preferred), along the path, at the receiver
✔✔Industrial Hygienist - ✔✔Responsible for assessment of hazards that may affect
workers as well as hazards that may impact the community.
✔✔NRR - ✔✔Noise Reduction Rating; number determined in a laboratory
✔✔Hearing protection derating - ✔✔OSHA recommends to reduce NRR in half
✔✔Hearing protection types - ✔✔Noise reduction devices worn over the ear (noise
muffs) or inside the ear canal (earplugs) in work or recreational settings with high noise
levels
✔✔Best hearing protection - ✔✔The one that is worn (consistently and properly)
✔✔Dual hearing protection NRR - ✔✔After derating add additional 5dB of protection
✔✔Inverse square law for noise - ✔✔For every doubling of distance away from a noise
source you reduce the level by 6 dB
✔✔Noise doubling rule - ✔✔If you add two identical noise sources you add 3dB to the
Level (100 dB + 100 dB = 103 dB)
✔✔Administrative noise controls - ✔✔Changes made by employer such as changing
work schedules to reduce noise hazard risk to employees
SOLUTIONS RATED A+
✔✔Sound pressure level (SPL) versus hearing level (HL) - ✔✔SPL describes noise
measurements taken with a sound level meter or dosimeter; HL describes threshold
levels obtained with an audiometer; 0 dB HL is not equal to 0 dB SPL
✔✔Noise Dosimeter - ✔✔A sound measurement device used to record the amount of
sound exposure over an extended period of
time (usually a work day)
Personal vs. Area
✔✔Sound level meter - ✔✔Uses a microphone to sense pressure variations in sound
waves; the meter converts those pressures directly into decibels; provides a noise
measurement that is a snapshot in time.
✔✔Time Weighted Average (TWA) - ✔✔An evaluation of exposures that is time-
weighted over an established period. It allow the exposure levels to be averaged
generally over an eight-hour time period.
✔✔OSHA exchange rate - ✔✔5 dB; for every 5 dB you go over the PEL of 90dBA TWA
you half the allowable time of exposure
✔✔OSHA Action Level for noise - ✔✔85dBA TWA
✔✔Sound Level Meter A-weighted Scale - ✔✔OSHA requires this scale as it resembles
how the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz)
✔✔Human Frequency Response at Birth - ✔✔20 Hz to 20,000 Hz (20 kHz)
✔✔Human speech frequency range - ✔✔250 Hz to 4000 Hz
✔✔Elements of a Hearing Conservation Program - ✔✔Noise hazard assessment;
engineering/administrative controls; annual hearing monitoring; annual
training/education; hearing protection; recordkeeping
✔✔OSHA Noise Amendment - ✔✔29 CFR 1910.95
✔✔Hughson-Westlake Procedure - ✔✔Common procedure for obtaining threshold; the
audiologist decreases stimulus intensity by 10 dB with a (+) response and increases by
5 dB with a (-) response
✔✔Hearing threshold level - ✔✔Lowest intensity level responded to at least 50% of the
time
, ✔✔Excessive noise levels will impact these test frequencies during a hearing exam -
✔✔Low frequencies e.g. 500 Hz
✔✔First frequency always tested on an occupational hearing exam - ✔✔1000 Hz
✔✔1000 Hz retest - ✔✔Done as a validity check on first ear tested; thresholds should
be within 5dB or should reinstruct patient and start test over
✔✔Presbycusis - ✔✔A gradual loss of sensorineural hearing that occurs as the body
ages
✔✔Professional Supervisor In a HCP - ✔✔Responsible for oversight of Audiometric
testing; reviews problem audiograms; must be an audiologist or physician
✔✔Elements of a Hearing Conservation Program - ✔✔Mandatory and includes:
exposure monitoring, audiometric testing, hearing protection, employee training, record
keeping, and program evaluation
✔✔Noise Controls - ✔✔At the source (preferred), along the path, at the receiver
✔✔Industrial Hygienist - ✔✔Responsible for assessment of hazards that may affect
workers as well as hazards that may impact the community.
✔✔NRR - ✔✔Noise Reduction Rating; number determined in a laboratory
✔✔Hearing protection derating - ✔✔OSHA recommends to reduce NRR in half
✔✔Hearing protection types - ✔✔Noise reduction devices worn over the ear (noise
muffs) or inside the ear canal (earplugs) in work or recreational settings with high noise
levels
✔✔Best hearing protection - ✔✔The one that is worn (consistently and properly)
✔✔Dual hearing protection NRR - ✔✔After derating add additional 5dB of protection
✔✔Inverse square law for noise - ✔✔For every doubling of distance away from a noise
source you reduce the level by 6 dB
✔✔Noise doubling rule - ✔✔If you add two identical noise sources you add 3dB to the
Level (100 dB + 100 dB = 103 dB)
✔✔Administrative noise controls - ✔✔Changes made by employer such as changing
work schedules to reduce noise hazard risk to employees
