CAOHC Exam Study Questions and Answers Rated A
Unit of measurement for frequency (pitch) Hertz (Hz)
Unit of measurement for intensity (loudness) Decibel (dB)
Risk of damage from noise How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator Lasts 1 second or longer
Impulse or Impact noise, e.g. gunfire or nail gun Lasts less than one second
Parts of the outer ear Pinna and external auditory canal
Parts of the middle ear Tympanic membrane, ossicles, eustachian tube
Tube connecting the middle ear to the pharynx and equal-
Eustachian tube (auditory tube)
izes middle ear space with atmospheric pressure
Conductive HL occurs here Outer or middle ear
Hearing loss resulting from damage to the inner ear
Sensorineural hearing loss
(cochlea) or the auditory nerve
Condition caused by the destruction of hair cells in the
inner ear, the organs responsible for hearing, as a result
Noise-induced hearing loss (NIHL)
of sounds that are "too long, too loud, or too close"; a
sensorineural hearing loss
Combination of conductive and sensorineural types in the
Mixed hearing loss
same ear
Middle ear bones (ossicles) Malleus (hammer), incus (anvil), stapes (stirrup)
Possible early symptoms/signs of noise induced hearing Tinnitus; diflculty understanding in presence of back-
loss ground noise; read visual cues
Auditory ettects of noise NIHL; tinnitus; hyperacusis
annoyance
sleep disturbance
Non-auditory ettects of noise attention
motivation
stress reactions
1/7
, CAOHC Exam Study Questions and Answers Rated A
cardiovascular problems
endocrine problems
Good rule of thumb to recognize hazardous noise expo-
sure levels/situations: the rule is: if you have to shout at
arms length (~3ft), in order to be understood over the
3 foot rule
background noise, then you're likely exposed to hazardous
noise levels & should be wearing hearing protection to
prevent NIHL
OSHA (Occupational Safety and Health Administration)
OSHA enforces regulation and NIOSH recommends best
versus National institute of Occupational Safety and Heath
practice based on science and research
(NIOSH)
SPL describes noise measurements taken with a sound
level meter or dosimeter; HL describes threshold levels
Sound pressure level (SPL) versus hearing level (HL)
obtained with an audiometer; 0 dB HL is not equal to 0
dB SPL
A sound measurement device used to record the amount
of sound exposure over an extended period of
Noise Dosimeter
time (usually a work day)
Personal vs. Area
Uses a microphone to sense pressure variations in sound
waves; the meter converts those pressures directly into
Sound level meter
decibels; provides a noise measurement that is a snapshot
in time.
An evaluation of exposures that is time-weighted over
Time Weighted Average (TWA) an established period. It allow the exposure levels to be
averaged generally over an eight-hour time period.
5 dB; for every 5 dB you go over the PEL of 90dBA TWA you
OSHA exchange rate
half the allowable time of exposure
OSHA Action Level for noise 85dBA TWA
Sound Level Meter A-weighted Scale 2/7
Unit of measurement for frequency (pitch) Hertz (Hz)
Unit of measurement for intensity (loudness) Decibel (dB)
Risk of damage from noise How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator Lasts 1 second or longer
Impulse or Impact noise, e.g. gunfire or nail gun Lasts less than one second
Parts of the outer ear Pinna and external auditory canal
Parts of the middle ear Tympanic membrane, ossicles, eustachian tube
Tube connecting the middle ear to the pharynx and equal-
Eustachian tube (auditory tube)
izes middle ear space with atmospheric pressure
Conductive HL occurs here Outer or middle ear
Hearing loss resulting from damage to the inner ear
Sensorineural hearing loss
(cochlea) or the auditory nerve
Condition caused by the destruction of hair cells in the
inner ear, the organs responsible for hearing, as a result
Noise-induced hearing loss (NIHL)
of sounds that are "too long, too loud, or too close"; a
sensorineural hearing loss
Combination of conductive and sensorineural types in the
Mixed hearing loss
same ear
Middle ear bones (ossicles) Malleus (hammer), incus (anvil), stapes (stirrup)
Possible early symptoms/signs of noise induced hearing Tinnitus; diflculty understanding in presence of back-
loss ground noise; read visual cues
Auditory ettects of noise NIHL; tinnitus; hyperacusis
annoyance
sleep disturbance
Non-auditory ettects of noise attention
motivation
stress reactions
1/7
, CAOHC Exam Study Questions and Answers Rated A
cardiovascular problems
endocrine problems
Good rule of thumb to recognize hazardous noise expo-
sure levels/situations: the rule is: if you have to shout at
arms length (~3ft), in order to be understood over the
3 foot rule
background noise, then you're likely exposed to hazardous
noise levels & should be wearing hearing protection to
prevent NIHL
OSHA (Occupational Safety and Health Administration)
OSHA enforces regulation and NIOSH recommends best
versus National institute of Occupational Safety and Heath
practice based on science and research
(NIOSH)
SPL describes noise measurements taken with a sound
level meter or dosimeter; HL describes threshold levels
Sound pressure level (SPL) versus hearing level (HL)
obtained with an audiometer; 0 dB HL is not equal to 0
dB SPL
A sound measurement device used to record the amount
of sound exposure over an extended period of
Noise Dosimeter
time (usually a work day)
Personal vs. Area
Uses a microphone to sense pressure variations in sound
waves; the meter converts those pressures directly into
Sound level meter
decibels; provides a noise measurement that is a snapshot
in time.
An evaluation of exposures that is time-weighted over
Time Weighted Average (TWA) an established period. It allow the exposure levels to be
averaged generally over an eight-hour time period.
5 dB; for every 5 dB you go over the PEL of 90dBA TWA you
OSHA exchange rate
half the allowable time of exposure
OSHA Action Level for noise 85dBA TWA
Sound Level Meter A-weighted Scale 2/7
