Block #5 hearing
Bio responsibilities
Assess hazards, worksite visits, complete noise surveys and audiometric test environment
AF form 1753
Audiometric case history
Receiver
Auditory mechanism to receive and interpret the signal
Sender
The source of vibration and the source of energy needed to initiate vibration
Frequency
The speed at which sound vibrates determines it (blank) and pitch
Who must Be motivated to take the steps necessary to Preserve their hearing health
The worker
Microprocessor Audiometer
"Standalone" audiometer that uses a microchip controlled program to automatically present test tones
What calibration test are performed by MERC
Annual electroacoustic calibration and biannual exhausted calibration
What are the three types of calibration
Annual electroacoustic calibration, biannual exhaustive calibration, Daily biological calibration checks
Rising configuration
Are not caused by noise and are typically conducted in nature
Electrocoustic ear (bio joe)
Artificial ear is used to verify calibration status of the audio meter during biological calibration checks
Normal hearing
Is considered to be any threshold below 25 dB. 0 dB is considered to be the average best hearing
Noise
Is considered to be unwanted sound
Noise dose
Is the % of an allowable noise exposure the worker experiences through the work day.
Decibel exchange rate
Is the amount of (blank) increase/decrease in the noise exposure causing the noise dose to double
bone conduction
Masking are parts of the diagnostic evaluation performed by audiologist To prevent cross over
Mil-STD 1474
Maximum noise limits
5 auditory effects of noise
TTS- temporary threshold shift PTS- permanent threshold shift Social withdrawal Tinnitus Hyperausis
Command level players responsibilities
Developing policies and allocating resources to facilitate effective programs
Lighted ear inspection test are performed when
Prior to all audiometric test and hearing protective device fittings
The human ear is sensitive to frequencies as low as (blank) and as high as (blank)
20Hz and 20,000Hz
NIOSH uses a (blank) exchange rate
3dBA
The range intensity range for human ears are?
0-140dB
The human ear is most sensitive to sounds in the range of (blank) to (blank)
1000 Hz to 4000Hz
BE is responsible for what two of the five elements in ACMED?
A (noise assessment) and C (noise control)
sound level meter
A device that uses a microphone and basic electronic processing to measure and convert the pressure fluctuations.
OSHA 29 CRF 1910.95
A regulation regarding hearing conservation states all programs must limit noise exposure
Sounds waves
A series of compressions and rarefactions make up a sounds wave producing a series of alternating areas of high and low pressure
Serial Audiogram
Air conduction threshold numberically
Supervisor responsibilities
All new personnel in noise hazardous duty are trained by PH, fitted for HPD, baseline audiogram
Mini booth
Best in environments with BGN of <65 dBA during The busiest part of the day
Who determines if a shop needs double hearing protection
Bio environmental engineering
vestibular system
Carries signals from Oregon to brain
Central auditory system
Carries signals from hearing and balance from inner ear through the brain Stem to the brain
Medium
Carries the pressure change
What parts make up the inner ear
Cochlea and vestibular system
pinna function
Collect sound and direct to ear canal
Complex tones
Combination of sound waves with a mix of frequencies
Hierarchy of controls
Component used to determine which control solutions are most feasible and effective
SF 600 (Chronological Record of Medical Care)
Date, type of HPD, brand and noise attenuation provided and resulted noise level
Graphic Audiograms
Displayed on a chart using symbols to identify thresholds
double distance away from the sound sources
Doubling the distance from a sound source this intensity of the exposure will decrease by 6 dB (inverse law)
Types of hearing protective devices
Ear plugs, ear muffs, branded hearing Protectors, non-standard devices/special protectors, Double hearing protection
Reference Audiogram
Employees best hearing and serve as baseline for future comparisons recorded on DD form 2215
Engineering controls
First choice to reduce Hazardous noise exposure existing in the workplace
Personal requiring audiometric monitoring
For workers with routine exposure to 85 dBA 8hrs or 140 dBA/Ultrasonic exposure
What are calibrated to a specific audio meter and must Not be interchanged with another device without recalibrating
Headphones
Manual Audiometer
Gives the operator the ability to focus on Problem frequencies that the patient might be consistently missing
sensorineural hearing loss
Hair cells in the cochlea or nerve pathway to the brain are damaged and or lost, Typically permanent and untreatable
Sound
Is a sensation that results from stimulation of the auditory mechanism
Unilateral hearing loss
Hearing loss that occurs in only one ear
The 3 ft role
If you need to shout to be understood from 3 ft away it's a potential hazard
DODi 6055.7
Implements OHSA reports and requirements for DOD
Intensity
Loudness/ volume/ amplitude
Ossicle chain
Malleus, incus, stapes
Compression
Molecules are forced together causing an area of high pressure
Employees Responsibilities
Must comply with all recommend noise control measures
Non-organic hearing loss
No medical or physical reason for the loss
5 elements of AF hearing conservation program
Noise assessment Noise control Audiometric monitoring Education Disposition
Occupational noise
Noise source that exist in the workplace
Hearing conservation directives
OSHA- 29 CFR 1910.95 DODI- 6055.12 AFI 48-127
Conductive hearing loss
Pathway of sound is block in the inner ear and the middle ear some loss of hearing will occur
cochlea function
Snail like structure Embedded deeply in the temporal bone of the skull
Who is responsible for initial earplug fitting during referral audiogram
Public health
Who is responsible for training personnel on the proper use and care of hearing protective devices at the time of audiometric testing
Public health
What is the goal for noise assessment
Quantify the workers noise exposure and determine health risk caused by these exposures
AFI 48-127
Quantifying noise hazards (Bios responsibility)
Non-occupational noise
Recreational noise that can come sources such as hunting (outside of the workplace)
Purpose for HPD
Reduce noise exposure at the ear of the worker
AFI 48-127
Regulates noise exposure limits and est. responsibilities for noise evaluation and control
OEHWG responsibilities
Review all occ. exposures, determine what type of test should be required to monitor workers exposure
Occ. Health consultant responsibilities
Review audiograms and determine employees hearing loss is work related
DODi 6055.1
SOH metrics as PTS rates DOD personnel
What are the 3 requirements for sound
Sender, medium, receiver
tympanic membrane function
Separate outer ear from the inner. Vibrates in response to acoustic energy
Pure tones
Simplest form of sound and represents one frequency
Vibration
Sound creates vibration it causes alternate pressure changes in the air molecules surrounding it.
Tinnitus
Sounds in the ear or head without an external source
Mobile booths
Sounds treated enclosed with Van, bus or trailer
Time weighted average
The amount of the time a worker is exposed to hazardous noise over the work day-8hrs
sloping configuration
The most common audiometric pattern especially for those who work in Noise and are getting older
The best HPD what?
The one the worker will wear correctly
Mixed hearing loss
The person that has a combination of conductive and sensorineural loss
Standard booth
They have heavier walls and more storable for areas where BGN levels are 65-79 dBA 3-4in walls
What is the goal for establishing threshold
To find the softest decimal level a person is able to hear
What is the main purpose of NRR Noise reduction rating
To help the customer choose the right brand/style of HP Des from a variety of options
Periodic audiogram
To identify early changes in hearing by comparing the most great audiogram to a valid reference audio gram to calculate threshold shifts and determine if Intervention is needed documented on DD form 2216
Mission of hearing conservation
To prevent noise induced hearing loss
What is the purpose for the lighted ear inspection
To rule out any abnormalities that would affect a subject ability to receive audiometric testing
DODi 6055.12
Tri-serivce that mandates each service meets guidelines and develops service specific regulations
What parts make up the middle ear
Tympanic membrane, malleus, incus, stapes, eustanchian Membrane
Hand Switch
Used by the listener to indicate a response
non-organic hearing loss
Usually indicates a conductive hearing loss caused by infection chronic allergies or TM abnormalities
Rarefaction
When Molecules separate for each-other causing an area of low pressure
Double hearing Protection is required when
With any noise with a TWA greater than 100 dBA
Administrative controls
Worker rotation to remove noise exposed workers out of noisy areas to revent them from reaching PELs
Amplification
Workers with existing hearing loss may be fitted with hearing aids to help remedy the loss but hearing aids cannot restore normal hearing
Asymmetric hearing loss
hearing loss occurs in both ears But one is significantly worse
Hyperacusis
increased sensitivity to sound
What part makes up the outer ear
pinna