NIHL
What is Noise Induced Hearing Loss?
long term hearing loss due to repeated exposure over years
What can an audiologist do in regards of prevention for NIHL
Inform, wear hearing protection, be alert to hazardous noise in the workplace, protect children, base-line audiogram, public awareness
What type of hearing protection can provide a constant protection but are uncomfortable and hot?
Ear Muffs
What is hearing impairment in Elderly patients often confused with?
Depression, confusion, inattentiveness, increased tension, negativism, etc.
What is presbycusis?
Hearing loss resulting from the aging process
What is acoustic trauma?
permanent cochlear damage after ONE exposure to very high SPLs
Noise is likely too loud if...
louder than conversational levels, muffled hearing following exposure
What type of hearing protection are disposable, comfortable, attenuates high frequencies more than lows, affordable?
Foam Earplugs
Advantages of identification and assessment of presbycusis?
Important for social, psychological and economic reasons as well as increased success with hearing aids and brain plasticity
What is the typical hearing loss associated with ARHL?
Bilateral, symmetric SNHL with high frequencies being most affected
How much is too much noise exposure according to OSHA?
8 hours at 85 dBA
According to an old rule, what can you use to predict a permanent threshold shift?
Multiple temporary threshold levels
What hearing protection fit to the individual ear and have a flat frequency spectrum?
Custom Ear Plugs
What are some screening tools that we can use to identify and assess for presbycusis?
Hearing Handicap Inventory for the Elderly or Screening (at entry to medicare)
According to some research, what are some underlying physiological effects of ARHL?
Even a moderate decline in HL can impact neural activity which is important for speech processing.
May impact the volume of gray matter in the primary auditory cortex
Give 3 examples of recreational noise
cap guns, go-karts, concerts, guns, fire-crackers, chain-saws, playing in a band, snowmobiles, iPods, etc
What is the new view of NIHL?
Recognizes that noise that causes TTS may actually have long term effects/ permanent consequences may not be apparent in pure tone thresholds for many years
What type of hearing protection do musicians typically use?
Custom ear plugs
What is a challenge when it comes to treatment and rehabilitation regarding presbycusis?
Difficulty separating effects of aging from effects of noise exposure (NIHL)
What are some physical effects of aging on the outer and middle ear?
Loss of tissue elasticity of pinna and EC, stiffening of TM, degeneration of middle ear musculature, calcification of ligaments, ossification of ossicles, etc.
What might you expect the audiogram to look like for a patient who has permanent threshold shift following noise exposure?
Bilateral, sensorineural sloping hearing loss
High frequency loss will rarely exceed 75 dBHL, and low frequency loss will rarely exceed 40 dBHL
You MIGHT see a notch around 4 kHz, but you might not
Loss will always be greater from 3-6 kHz than .5-2 kHz
What is the equal energy hypothesis?
equal amounts of sound energy will produce equal amounts of hearing impairment regardless of how the sound energy is distributed in time
--> This is not a biologically accurate hypothesis
What frequencies do hearing protection TYPICALLY attenuate more?
High frequencies
What are some functions of the efferent system?
Gain control, inhibit cochlear amplifier, role in signal detection in noise, protective role during acoustic over-stimulation.
What might be a typical case of sensory presbycusis?
Bilateral precipitous high frequency SNHL with initially equal speech discrimination ability