Noise exposure
hearing conservation
Noise exposure and hearing loss
Constant exposure to loud noises leads to sensorineural hearing loss
1 in 4 adults age 20-69 in the US have evidence of noise-induced hearing loss
33% of adults who reported exposure to loud noise at work had impaired hearing
3 segments of the ear
Outer ear - auricle and ear canal
Middle ear - TM, ossicles, middle ear space
Inner ear - cochlea, semicircular canals, internal auditory canals
Ear physiology
Sound waves "caught" by the auricle then funnel down the EAC
Sound waves vibrate the TM which causes motion of the ossicles and a piston motion of the
stapes
Motion of the stapes pushes the inner ear fluid around the cochlea
Fluid waves in the cochlea set into motion the organ of Corti
- Movement of the organ of Corti bends the sterocilia which sends impulse via the cochlear
nerve to the brain where this is interpreted
Physics of sound
To make a sound, there must be a vibration
Sounds waves consist of vibrating particles
Sound waves are longitudinal - wave in which the particles of the medium oscillate parallel to
the direction of propagation of the wave
- Areas of high pressure = compressions
- Areas of low pressure = rarefactions
, Sound
A vibration that propagates as a mechanical wave of pressure and displacement conducted
through a media - fluid, air
Frequency
The rate at which a vibration occurs that constitutes a wave
Cycles per second (Hertz; Hz)
Decibel
unit used to measure the intensity of a sound (dB)
3 types of hearing loss
Conductive
- Involves any cause that limits the amount of external sound from gaining access to the
inner ear
- Often reversible
Sensorineural
- Involves the inner ear, cochlea or auditory nerve
- Permanent
Mixed
- Combination of both
Conductive hearing loss outer ear
- Cerumen
- Infection
- Trauma
- Tumor
- Dermatologic - psoriasis
Conductive hearing loss middle ear
- Eustachian tube dysfunction
- Otitis media
- Cholesteatoma
- TM perforation
- Barotrauma-Sudden change in pressure - flying, deep sea diving
hearing conservation
Noise exposure and hearing loss
Constant exposure to loud noises leads to sensorineural hearing loss
1 in 4 adults age 20-69 in the US have evidence of noise-induced hearing loss
33% of adults who reported exposure to loud noise at work had impaired hearing
3 segments of the ear
Outer ear - auricle and ear canal
Middle ear - TM, ossicles, middle ear space
Inner ear - cochlea, semicircular canals, internal auditory canals
Ear physiology
Sound waves "caught" by the auricle then funnel down the EAC
Sound waves vibrate the TM which causes motion of the ossicles and a piston motion of the
stapes
Motion of the stapes pushes the inner ear fluid around the cochlea
Fluid waves in the cochlea set into motion the organ of Corti
- Movement of the organ of Corti bends the sterocilia which sends impulse via the cochlear
nerve to the brain where this is interpreted
Physics of sound
To make a sound, there must be a vibration
Sounds waves consist of vibrating particles
Sound waves are longitudinal - wave in which the particles of the medium oscillate parallel to
the direction of propagation of the wave
- Areas of high pressure = compressions
- Areas of low pressure = rarefactions
, Sound
A vibration that propagates as a mechanical wave of pressure and displacement conducted
through a media - fluid, air
Frequency
The rate at which a vibration occurs that constitutes a wave
Cycles per second (Hertz; Hz)
Decibel
unit used to measure the intensity of a sound (dB)
3 types of hearing loss
Conductive
- Involves any cause that limits the amount of external sound from gaining access to the
inner ear
- Often reversible
Sensorineural
- Involves the inner ear, cochlea or auditory nerve
- Permanent
Mixed
- Combination of both
Conductive hearing loss outer ear
- Cerumen
- Infection
- Trauma
- Tumor
- Dermatologic - psoriasis
Conductive hearing loss middle ear
- Eustachian tube dysfunction
- Otitis media
- Cholesteatoma
- TM perforation
- Barotrauma-Sudden change in pressure - flying, deep sea diving
