CAOHC STUDY GUIDE |ACTUAL EXAM QUESTIONS AND WELL DE-
TAILED VERIFIED SOLUTIONS| GRADED A+| BRAND NEW 2026/2027
UPDATE
Unit of measurement for intensity (loudness) - ANSWER Decibel (dB)
Unit of measurement for frequency (pitch) - ANSWER Hertz (Hz)
Risk of damage from noise - ANSWER How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator - ANSWER Lasts 1 second or longer
Impulse or Impact noise, e.g. gunfire or nail gun - ANSWER Lasts less than one second
Parts of the outer ear - ANSWER Pinna and external auditory canal
Parts of the middle ear - ANSWER Tympanic membrane, ossicles, eustachian tube
Eustachian tube (auditory tube) - ANSWER Tube connecting the middle ear to the phar-
ynx and equalizes middle ear space with atmospheric pressure
Conductive HL occurs here - ANSWER Outer or middle ear
Sensorineural hearing loss - ANSWER Hearing loss resulting from damage to the inner ear
(cochlea) or the auditory nerve
Mixed hearing loss - ANSWER Combination of conductive and sensorineural types in the
same ear
1
, Noise-induced hearing loss (NIHL) - ANSWER Condition caused by the destruction of hair
cells in the inner ear, the organs responsible for hearing, as a result of sounds that are "too
long, too loud, or too close"; a sensorineural hearing loss
Middle ear bones (ossicles) - ANSWER Malleus (hammer), incus (anvil), stapes (stirrup)
Possible early symptoms/signs of noise induced hearing loss - ANSWER Tinnitus; difficulty
understanding in presence of background noise; read visual cues
Auditory effects of noise - ANSWER NIHL; tinnitus; hyperacusis
Non-auditory effects of noise - ANSWER annoyance
sleep disturbance
attention
motivation
stress reactions
cardiovascular problems
endocrine problems
3 foot rule - ANSWER Good rule of thumb to recognize hazardous noise exposure lev-
els/situations: the rule is: if you have to shout at arms length (~3ft), in order to be under-
stood over the 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) versus National institute of Occupa-
tional Safety and Heath (NIOSH) - ANSWER OSHA enforces regulation and NIOSH recom-
mends best practice based on science and research
2
TAILED VERIFIED SOLUTIONS| GRADED A+| BRAND NEW 2026/2027
UPDATE
Unit of measurement for intensity (loudness) - ANSWER Decibel (dB)
Unit of measurement for frequency (pitch) - ANSWER Hertz (Hz)
Risk of damage from noise - ANSWER How loud (intensity) and how long (duration)
Steady-state or continuous noise, e.g. generator - ANSWER Lasts 1 second or longer
Impulse or Impact noise, e.g. gunfire or nail gun - ANSWER Lasts less than one second
Parts of the outer ear - ANSWER Pinna and external auditory canal
Parts of the middle ear - ANSWER Tympanic membrane, ossicles, eustachian tube
Eustachian tube (auditory tube) - ANSWER Tube connecting the middle ear to the phar-
ynx and equalizes middle ear space with atmospheric pressure
Conductive HL occurs here - ANSWER Outer or middle ear
Sensorineural hearing loss - ANSWER Hearing loss resulting from damage to the inner ear
(cochlea) or the auditory nerve
Mixed hearing loss - ANSWER Combination of conductive and sensorineural types in the
same ear
1
, Noise-induced hearing loss (NIHL) - ANSWER Condition caused by the destruction of hair
cells in the inner ear, the organs responsible for hearing, as a result of sounds that are "too
long, too loud, or too close"; a sensorineural hearing loss
Middle ear bones (ossicles) - ANSWER Malleus (hammer), incus (anvil), stapes (stirrup)
Possible early symptoms/signs of noise induced hearing loss - ANSWER Tinnitus; difficulty
understanding in presence of background noise; read visual cues
Auditory effects of noise - ANSWER NIHL; tinnitus; hyperacusis
Non-auditory effects of noise - ANSWER annoyance
sleep disturbance
attention
motivation
stress reactions
cardiovascular problems
endocrine problems
3 foot rule - ANSWER Good rule of thumb to recognize hazardous noise exposure lev-
els/situations: the rule is: if you have to shout at arms length (~3ft), in order to be under-
stood over the 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) versus National institute of Occupa-
tional Safety and Heath (NIOSH) - ANSWER OSHA enforces regulation and NIOSH recom-
mends best practice based on science and research
2
