CAOHC EXAM ELABORATIONS QUESTIONS
AND ANSWERS.(16/20) LATEST UPDATE 2025
QUESTION: Unit of measurement for frequency (pitch) - ANSWER-Hertz (Hz)
QUESTION: Unit of measurement for intensity (loudness) - ANSWER-Decibel (db)
QUESTION: Risk of damage from noise - ANSWER-How loud (intensity) and how long
(duration)
QUESTION: Steady-state or continuous noise, e.g. Generator - ANSWER-Lasts 1 second or
longer
QUESTION: Impulse or Impact noise, e.g. Gunfire or nail gun - ANSWER-Lasts less than one
second
QUESTION: Parts of the outer ear - ANSWER-Pinna and external auditory canal
QUESTION: Parts of the middle ear - ANSWER-Tympanic membrane, ossicles, eustachian tube
,QUESTION: Eustachian tube (auditory tube) - ANSWER-Tube connecting the middle ear to the
pharynx and equalizes middle ear space with atmospheric pressure
QUESTION: Conductive HL occurs here - ANSWER-Outer or middle ear
QUESTION: Sensorineural hearing loss - ANSWER-Hearing loss resulting from damage to the
inner ear (cochlea) or the auditory nerve
QUESTION: Noise-induced hearing loss (NIHL) - ANSWER-Condition caused by the
destruction of hair cells, the organs responsible for hearing, as a result of sounds that are "too
long, too loud, or too close"; a sensorineural hearing loss
QUESTION: Mixed hearing loss - ANSWER-Combination of conductive and sensorineural
types in the same ear
QUESTION: Middle ear bones (ossicles) - ANSWER-Malleus (hammer), incus (anvil), stapes
(stirrup)
QUESTION: Possible early symptoms/signs of noise induced hearing loss - ANSWER-Tinnitus;
difficulty understanding in presence of background noise; read visual cues
QUESTION: Auditory effects of noise - ANSWER-NIHL; tinnitus; hyperacusis
,QUESTION: Non-auditory effects of noise - ANSWER-annoyance
Sleep disturbance
Attention
Motivation
Stress reactions
Cardiovascular problems
Endocrine problems
QUESTION: 3 foot rule - ANSWER-Good rule of thumb to recognize hazardous noise exposure
levels/situations: the rule is: if you have to shout at arms length (~3ft), in order to be understood
over the background noise, then you're likely exposed to hazardous noise levels & should be
wearing hearing protection to prevent NIHL
QUESTION: OSHA (Occupational Safety and Health Administration) versus National institute
of Occupational Safety and Heath (NIOSH) - ANSWER-OSHA enforces regulation and NIOSH
recommends best practice based on science and research
QUESTION: Sound pressure level (SPL) versus hearing level (HL) - ANSWER-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
, QUESTION: Noise Dosimeter - ANSWER-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
QUESTION: Sound level meter - ANSWER-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.
QUESTION: Time Weighted Average (TWA) - ANSWER-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.
QUESTION: OSHA exchange rate - ANSWER-5 db; for every 5 db you go over the PEL of
90dba TWA you half the allowable time of exposure
QUESTION: OSHA Action Level for noise - ANSWER-85dba TWA
QUESTION: Sound Level Meter A-weighted Scale - ANSWER-OSHA requires this scale as it
resembles how the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz
QUESTION: Human Frequency Response at Birth - ANSWER-20 Hz to 20,000 Hz (20 khz)
AND ANSWERS.(16/20) LATEST UPDATE 2025
QUESTION: Unit of measurement for frequency (pitch) - ANSWER-Hertz (Hz)
QUESTION: Unit of measurement for intensity (loudness) - ANSWER-Decibel (db)
QUESTION: Risk of damage from noise - ANSWER-How loud (intensity) and how long
(duration)
QUESTION: Steady-state or continuous noise, e.g. Generator - ANSWER-Lasts 1 second or
longer
QUESTION: Impulse or Impact noise, e.g. Gunfire or nail gun - ANSWER-Lasts less than one
second
QUESTION: Parts of the outer ear - ANSWER-Pinna and external auditory canal
QUESTION: Parts of the middle ear - ANSWER-Tympanic membrane, ossicles, eustachian tube
,QUESTION: Eustachian tube (auditory tube) - ANSWER-Tube connecting the middle ear to the
pharynx and equalizes middle ear space with atmospheric pressure
QUESTION: Conductive HL occurs here - ANSWER-Outer or middle ear
QUESTION: Sensorineural hearing loss - ANSWER-Hearing loss resulting from damage to the
inner ear (cochlea) or the auditory nerve
QUESTION: Noise-induced hearing loss (NIHL) - ANSWER-Condition caused by the
destruction of hair cells, the organs responsible for hearing, as a result of sounds that are "too
long, too loud, or too close"; a sensorineural hearing loss
QUESTION: Mixed hearing loss - ANSWER-Combination of conductive and sensorineural
types in the same ear
QUESTION: Middle ear bones (ossicles) - ANSWER-Malleus (hammer), incus (anvil), stapes
(stirrup)
QUESTION: Possible early symptoms/signs of noise induced hearing loss - ANSWER-Tinnitus;
difficulty understanding in presence of background noise; read visual cues
QUESTION: Auditory effects of noise - ANSWER-NIHL; tinnitus; hyperacusis
,QUESTION: Non-auditory effects of noise - ANSWER-annoyance
Sleep disturbance
Attention
Motivation
Stress reactions
Cardiovascular problems
Endocrine problems
QUESTION: 3 foot rule - ANSWER-Good rule of thumb to recognize hazardous noise exposure
levels/situations: the rule is: if you have to shout at arms length (~3ft), in order to be understood
over the background noise, then you're likely exposed to hazardous noise levels & should be
wearing hearing protection to prevent NIHL
QUESTION: OSHA (Occupational Safety and Health Administration) versus National institute
of Occupational Safety and Heath (NIOSH) - ANSWER-OSHA enforces regulation and NIOSH
recommends best practice based on science and research
QUESTION: Sound pressure level (SPL) versus hearing level (HL) - ANSWER-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
, QUESTION: Noise Dosimeter - ANSWER-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
QUESTION: Sound level meter - ANSWER-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.
QUESTION: Time Weighted Average (TWA) - ANSWER-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.
QUESTION: OSHA exchange rate - ANSWER-5 db; for every 5 db you go over the PEL of
90dba TWA you half the allowable time of exposure
QUESTION: OSHA Action Level for noise - ANSWER-85dba TWA
QUESTION: Sound Level Meter A-weighted Scale - ANSWER-OSHA requires this scale as it
resembles how the human ear responds to sound (humans hear best from 500 Hz to 4000 Hz
QUESTION: Human Frequency Response at Birth - ANSWER-20 Hz to 20,000 Hz (20 khz)
