US Army: Hearing Loss Prevention short
Transcript of US Army: Hearing Loss Prevention short
8/14/2019 US Army: Hearing Loss Prevention short
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1LT SCOTT FORBES 1LT SCOTT FORBES
285-6186/6288 285-6186/6288
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DID YOU KNOW…...?-Noise-induced hearing loss is the
number one occupational disability
-It is generally painless-It is progressive over time
-
It is permanent-IT IS PREVENTABLE!!!
THE THE
4 PS 4 PS
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HOW DO WE HEAR?HOW DO WE HEAR?
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SOUND RECEPTORSSOUND RECEPTORS
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DAMAGED HAIR CELLSDAMAGED HAIR CELLS
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WHAT IS NOISE?
• Simply stated…noise is any
unwanted sound
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WAYS TO CHARACTERIZE
OF NOISE• FREQUENCY - perceived as pitch
• INTENSITY - perceived as loudness
• NATURE - steady-state vs. impulse/impact
• DURATION - length of time exposed
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Noise Induced Hearing Loss
u Initially, exposure to noise causes aloss of sensitivity to high frequency
(high pitch) sound.uContinued exposure results in damage
to mid frequency region as well.u
One can experience progressive highfrequency hearing loss and not beaware of it until it becomes severe(doesn’t affect loudness perception).
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HOW CAN IT HAPPEN?
ACOUSTIC TRAUMA – ONE TIMEEXPOSURE TO LOUD SOUND
OR
DAILY EXPOSURES TOMODERATELY LOUD SOUNDS
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HOW DO WE KNOW
SOMETHING IS TOO LOUD?• Could use 3 foot rule
– If you have to raise your voice to be
heard by someone standing within 3 foot(arm’s length) then the level is mostlikely above the hazardous noise level
or– Objectively measure loudness withproper equipment
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When isWhen is noisenoise scientificallyscientifically
defined to be adefined to be a hazardhazard??-Duration of exposure, intensity (volume)
of sound, repeated exposure, individual
susceptibility
-85dBA for steady-state noise sources
-140dBP for impulse/impact noise sources
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Steady-StateSteady-State
Noise ExamplesNoise Examplesu Rustling Leaves 20dB
u Conversation 60dB
uAutomobile 70dB
u Alarm Clock 80dB
u Screaming Child 90dB
u Pneumatic Drill 100dBu Helicopter 110dB
u Live Concert 130dB
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Loss of hearing sensitivity due to
hazardous noise exposures fromeither steady state noise orimpulse noise does occur even
before we can measure thechange!….
And it does carry negativeconsequences!!!
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PTS vs. TTS• A permanent threshold shift (PTS) vs. a
temporary threshold shift (TTS)
• Bounce-back effect…not complete recovery
• Immediate medical referral (Audiology /ENT)
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Permanent Effects of Noise
Induced Hearing Loss
-Difficulty understanding conversation,
particularly in background noise…highfrequency hearing loss affects abilityto hear consonants. Quality ofenvironmental sound is diminished.
-”Ringing in Ears” - tinnitus
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WHAT ABOUT EFFECTS
ON MISSION ???
• Hearing vs. vision in tacticalenvironment– Darkness
– 360 degrees
– 24/7
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What About the Soldier whoWhat About the Soldier whoCan’t Hear Within NormalCan’t Hear Within Normal
Hearing Range?Hearing Range?
uA normal listener can hearufootsteps at 100 metersuvoices at 180 metersurifle bolt closing at 1000 meters
u A person with a hearing loss can hearufootsteps at < 1 meter
uvoices at 32 metersurifle bolt closing at 46 meters
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THINK ABOUT IT…
-Listening posts
-Walking point onpatrol
-Call for fire
-Urban Warfare
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Annual Hearing TestingAnnual Hearing Testing
ÌWhy do annually?ÌFeedback BEFORE it becomes a
problem….not five years down the roadwhen it definitely is a problem
ÌWhat is your score???Ì Are you practicing good hearing
conservation or aren’t you???
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BOTTOM LINE
• If you are exposing yourself to
hazardous noise levelsunprotected…it’s not a matterof whether you will develop
hearing loss but when you willdevelop hearing loss…the oddsare VERY RARELY beaten.
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HEARING PROTECTION
¢The only thing standing between youand a potential permanent hearing
loss!!!!!
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But I Can’t Wear HearingBut I Can’t Wear Hearing
Protection Because…...Protection Because…...
ÌMy ears will become infected
ÌThey hurt my earsÌI can’t hear to do my jobÌI can’t hear sounds needed to hunt,
etc., etc.ÌThinking short-term instead of long-
term
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Approved Types of HPD’sApproved Types of HPD’s
²Earplugs²Pre-formed
²Hand-formed
²Noise Muffs
²Helmets
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NOISE REDUCTIONNOISE REDUCTION
RATING (NRR)RATING (NRR)rAll hearing protection deviceshave a Noise Reduction Rating(NRR)rField testing suggests that the
actual NRR is approximatelyhalf of what is listed on thepackage
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PRE-FORMED EARPLUGSPRE-FORMED EARPLUGS• Single Flange:
– (NRR)=23dB
– 5 color-coded sizes:• White (Extra Small)- 10% of
the population
• Green (Small)- 25%
• Orange (Medium)-30%
• Blue (Large)- 40%• Red (Extra Large)- 25%
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FITTING TECHNIQUEFITTING TECHNIQUE
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PRE-FORMED EARPLUGSPRE-FORMED EARPLUGS• Triple Flange:
– NRR= 26dB
– 3 color coded sizes:
• Green (Small)= 10% of thepopulation
• Orange (Medium)=80%
• Blue (Large)= 30%
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FITTING TECHNIQUEFITTING TECHNIQUE
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FITTING TECHNIQUEFITTING TECHNIQUE
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Characteristics Of A GoodCharacteristics Of A Good
Pre-formed Earplug FitPre-formed Earplug Fit²Voices sound muffled
²“Vacuum” effect
²Comfortable
²Single flange tab facing towardback of ear
²Largest flange of triple flange isflush against ear canal opening
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HAND-FORMED EARPLUGSHAND-FORMED EARPLUGS Noise Reduction Rating (NRR)=29dB
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Fitting TechniqueFitting Technique
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Circumaural Noise MuffsCircumaural Noise Muffs
Noise Reduction Rating(NRR)=23dB
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Fitting TechniqueFitting Technique
²Noise muffs should seal around theear
²Replace ear cushions when cracked orworn²Certain types of muffs allow
placement of the headband on top ofthe head, behind the head, or underthe chin
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Care and Maintenance ofCare and Maintenance ofall HEARING PROTECTIVEall HEARING PROTECTIVE
DEVICESDEVICES uKeep clean with mild soap and water
and dry before usinguReplace when material
hardens/cracks or does not cleanu
Check for cracks on earphone seals,headband tension and replace asneeded
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Helmets: For Specific
Operational Uses
• Aviators, aviationcrews
• Tankers
• Amphibious vehiclecrew members
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COMBAT EARPLUGSCOMBAT EARPLUGS•Insert YELLOW plugs for
weapons fire in dismountedmode.
• Insert OLIVE DRAB plugs for
steady state noise in andaround aircraft, noisy vehiclesand watercraft, etc.
• Keep filter holes free of earwax and other debris.
• Check proper insertion for slight tension by gently tuggingon plugs.
• Ensure that plugs are cleaned with soap and water and drywhen returned to case.
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Where to get HearingWhere to get Hearing
ProtectionProtection rPre-formed – fitting done at Thomas
Moore Health Clinic on walk-in basis
rAll other types provided by unit and shouldbe included in budget
O Wh d
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One more time…When do Ineed to wear protection?
• Steady state noise measured at85dBA or greater
• Impulse noise measured at 140dBA orgreater
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Are HPDs always enough?
• Some military noise exposure may
exceed the protection offered byHPDs
• Synergistic effects
• Permanent damage can be minimizedwith HPD use
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OTHER PROTECTIVE
MEASURES
• Administrative Controls
• Double protection
• Medical intervention???
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ADMINISTRATIVE
CONTROLS
• Limit exposuretime by
implementing shiftwork schedules
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DOUBLING UP!
• Steady state
noises 120dBA orgreater
• Use of insert
earplugs andcircumauralearmuffs together
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Medical Research
(on the horizon) • Hazardous exposure initiates inner ear
oxidative process which results in hair celldeath cycle
• New medication may be able to limit permanent damage by arresting oxidativeprocess
• Time sensitive• NOT A SUB FOR HPDs!
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Listening through HPDs takespractice but the thresholdshift caused from wearing
them is temporary…the shift
caused from not protectingyourself could bepermanent!!!!
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TO SUMMARIZE……
² HEARING LOSS HAPPENS!
² Noise induced hearing loss is 100%
preventable
² Your hearing health starts with YOU while
at work or home
² If YOU don’t protect it YOU will lose it
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QUESTIONS??QUESTIONS??
Fort Hood Hearing Conservation Fort Hood Hearing Conservation Section Section