The Effects of Noise The Effects of Noise on Hearingon HearingHow to Protect your Ears from How to Protect your Ears from Damage by Loud SoundsDamage by Loud Sounds

Carol Rousseau, M.A., CCC-ACarol Rousseau, M.A., CCC-A

Clinical AudiologistClinical Audiologist

Rochester Hearing and Speech CenterRochester Hearing and Speech Center

Rochester, New YorkRochester, New York

5 March 20095 March 2009

Goals for PresentationGoals for Presentation

What is Noise?What is Noise? How we hear -- anatomy and How we hear -- anatomy and

physiology of the earphysiology of the ear How noise effects the earHow noise effects the ear Discuss and demonstrate various Discuss and demonstrate various

types of Hearing Protection types of Hearing Protection Devices (HPD)Devices (HPD)

What is Noise?What is Noise?

SubjectiveSubjective Unpleasant or unwanted soundUnpleasant or unwanted sound It is a by-product of many It is a by-product of many

industrial processesindustrial processes

What is Noise?What is Noise?

Exposure to high levels of noise Exposure to high levels of noise can cause hearing loss as well as can cause hearing loss as well as other health related issuesother health related issues

Anatomy of the EarAnatomy of the Ear

ConductiveConductive– Outer EarOuter Ear– Middle EarMiddle Ear

SensorineuralSensorineural– Inner EarInner Ear– Auditory NerveAuditory Nerve

CentralCentral– BrainBrain

Anatomy and PhysicsAnatomy and Physicsof the Earof the Ear

What is Noise-Induced What is Noise-Induced Hearing Loss?Hearing Loss? Caused by damage to the cochlea Caused by damage to the cochlea

due to the over stimulation of the due to the over stimulation of the inner ear structuresinner ear structures– Mechanical damageMechanical damage– Chemical damageChemical damage

What is Noise-Induced What is Noise-Induced Hearing Loss?Hearing Loss? Damage can occur in two Damage can occur in two

waysways– Sudden intense noise that can Sudden intense noise that can

cause an acoustic traumacause an acoustic trauma– Long-term exposure to intense Long-term exposure to intense

noisenoise

What is Noise-Induced What is Noise-Induced Hearing Loss?Hearing Loss? Extent of damage depends on the Extent of damage depends on the

intensity of noise and the intensity of noise and the duration of the exposureduration of the exposure– Noise louder than 85 db can cause Noise louder than 85 db can cause

damagedamage– Risk of hearing loss from noise Risk of hearing loss from noise

doubles with each 3 dB increase in doubles with each 3 dB increase in sound levelsound level

Decibel Exposure Time Decibel Exposure Time GuidelinesGuidelines

Continuous dB Permissible Exposure Time85 dB 8 Hours88 dB 4 Hours91 dB 2 Hours94 dB 1 Hour97 dB 30 Minutes100 dB 15 Minutes103 dB 7.5 Minutes106 dB 3.75 Minutes109 dB 1.875 Minutes112 dB .9375 Minutes115 dB .46875 Minutes

AudiogramAudiogramNoise-Induced Hearing LossNoise-Induced Hearing Loss

Healthy and Damaged Healthy and Damaged Hair CellsHair Cells

Physiologic Effects on Physiologic Effects on the Cochleathe Cochlea Loss of hearing sensitivityLoss of hearing sensitivity

– Especially in the High FrequenciesEspecially in the High Frequencies Loss of clarityLoss of clarity Decreased sound localizationDecreased sound localization Reduced tolerance to loud soundsReduced tolerance to loud sounds

Other Physiological Other Physiological EffectsEffects TinnitusTinnitus CardiovascularCardiovascular Mental HealthMental Health

Noise Combined with Noise Combined with Chemical AgentsChemical Agents Some substances may be more Some substances may be more

dangerous when combined with dangerous when combined with noise exposurenoise exposure– AspirinAspirin– Some antibiotics and chemotherapy Some antibiotics and chemotherapy

drugsdrugs– Industrial chemicals such as lead, Industrial chemicals such as lead,

styrene, carbon dioxide, and carbon styrene, carbon dioxide, and carbon disulfidedisulfide

Damage can either be Damage can either be Temporary or Temporary or PermanentPermanent Temporary Threshold Shift (TTS) it a temporary Temporary Threshold Shift (TTS) it a temporary

elevation of the hearing threshold at one or elevation of the hearing threshold at one or more frequenciesmore frequencies– Short-term exposure to noiseShort-term exposure to noise– Comes back after a period of restComes back after a period of rest

Permanent Threshold Shift (PTS) is a Permanent Threshold Shift (PTS) is a permanent elevation caused by damage to the permanent elevation caused by damage to the hair cells, which can not be regenerated once hair cells, which can not be regenerated once they are injuredthey are injured– Prolonged exposure to high noise levels over Prolonged exposure to high noise levels over

a period of timea period of time– Gradually causes permanent damageGradually causes permanent damage

Hearing Protection Hearing Protection DevicesDevices OccupationalOccupational RecreationalRecreational

Occupations Who May Occupations Who May Need HPDNeed HPD Industrial WorkersIndustrial Workers ConstructionConstruction MilitaryMilitary Musicians and Other Entertainment Musicians and Other Entertainment

ProfessionalsProfessionals FarmersFarmers Day Care WorkersDay Care Workers DentistsDentists PediatriciansPediatricians NursesNurses

Recreational ActivitiesRecreational Activities

MusicMusic– Stereo and Personal Listening Devices Stereo and Personal Listening Devices

(iPods)(iPods)– ConcertsConcerts– PerformingPerforming

Hunting and Target ShootingHunting and Target Shooting MotorcyclingMotorcycling Drag Races and NASCARDrag Races and NASCAR SnowmobilingSnowmobiling WoodworkWoodwork LawnworkLawnwork

Volume Settings and dB(A) Readings of a Volume Settings and dB(A) Readings of a Number of Popular Personal Listening Number of Popular Personal Listening DevicesDevices

Player Full Vol 3/4 Vol 1/2 Vol 1/4 Vol LowApple iPOD (15 GB) 120-125 107-111 98-101 80-83 68-72Creative Zen Nano Plus 114/118 105-109 85-92 77-82 67-75

Sony Walkman MP3/ATRAC3plus 108-115 98-104 85-94 78-83 55-62iRiver T10 115-122 105-112 98-106 88-92 70-79Dell Latitude D610 Laptop 112-114 108-114 102-108 85-96 74-77

Bratz-Liptunes MP3 115-120 112-115 90-94 69-72 45-50Disney Mix Stick 112-118 100-105 87-99 70-76 60-66

Types of HPDTypes of HPD

Ear PlugsEar Plugs Ear FiltersEar Filters Ear MuffsEar Muffs Semi-Aural ProtectorsSemi-Aural Protectors Custom Ear MoldsCustom Ear Molds In-the-Ear MonitorsIn-the-Ear Monitors

Ear PlugsEar Plugs

Generally made of soft polyurethane Generally made of soft polyurethane or silicone foam, waxor silicone foam, wax

One Size Fits AllOne Size Fits All Inserted into Ear CanalInserted into Ear Canal DisposableDisposable Attenuates 20-40 dBAttenuates 20-40 dB Reduces high frequencies more than Reduces high frequencies more than

low, giving a muffled soundlow, giving a muffled sound

Non-custom Foam Ear Non-custom Foam Ear PlugsPlugs 29db of 29db of

attenuationattenuation

Pre-molded Ear PlugsPre-molded Ear Plugs

Made of vinyl, Made of vinyl, silicone or rubbersilicone or rubber

Come in different Come in different sizes for fittingsizes for fitting

Re-usableRe-usable

Ear SealsEar Seals

Soft flanged ear Soft flanged ear sealsseals

Detachable cordDetachable cord

Ear FiltersEar Filters

Attenuates sound more evenly Attenuates sound more evenly through baffles or moving through baffles or moving diaphragmsdiaphragms

One size fits allOne size fits all

Non-custom Musicians’ Non-custom Musicians’ EarplugsEarplugs ER-20ER-20 Attenuates sound Attenuates sound

more evenly more evenly through baffles through baffles or moving or moving diaphragmsdiaphragms

No custom mold No custom mold needed needed

Ear MuffsEar Muffs

Circum-aural Circum-aural protectorsprotectors

AdjustableAdjustable

Semi-Aural ProtectorsSemi-Aural Protectors

Ear plugs tips Ear plugs tips connected to a connected to a headbandheadband

Usually one size Usually one size fits allfits all

Can be taken on/off Can be taken on/off quicklyquickly

Attenuation less Attenuation less than that of other than that of other HPDsHPDs

Custom-madeCustom-made Ear Molds Ear Molds General purpose General purpose

solid ear plugssolid ear plugs Custom molded Custom molded

for the individualfor the individual ReusableReusable

Industrial Ear PlugsIndustrial Ear Plugs

Custom molded Custom molded ear plugsear plugs

Attenuates Attenuates approximately 29 approximately 29 dBdB

Hunters Ear PlugsHunters Ear Plugs

Pressure valve Pressure valve for occasional for occasional high impact noisehigh impact noise

Allows normal Allows normal hearing until a hearing until a gun shot gun shot activates the activates the valvevalve

Motorcycle Ear PlugMotorcycle Ear Plug

Canal styleCanal style Comfort while Comfort while

wearing under a wearing under a helmethelmet

Also for sleepingAlso for sleeping

Swim PlugsSwim Plugs

For swimmersFor swimmers Kid with PE tubesKid with PE tubes

Exposure Ear PlugsExposure Ear Plugs

Keeps out the Keeps out the environment but environment but allows for allows for communicationcommunication

For surfers, dudeFor surfers, dude

Custom Musician Ear Custom Musician Ear PlugsPlugs a special filter allows the a special filter allows the

listener to hear music at a listener to hear music at a safe level without safe level without sacrificing sound qualitysacrificing sound quality

Instead of cutting out the Instead of cutting out the high frequencies, high frequencies, musician's plugs attenuate musician's plugs attenuate all the frequencies evenly all the frequencies evenly in relation to your hearing.in relation to your hearing.

Custom plugs come in ER-9 Custom plugs come in ER-9 , ER-15 or ER-25 filters, ER-15 or ER-25 filters

An audiologist or other An audiologist or other hearing health professional hearing health professional takes impressions of the takes impressions of the ear canal.ear canal.

In-the-Ear MonitorsIn-the-Ear Monitors

Provide up to 25 Provide up to 25 dB of attenuation dB of attenuation from ambient from ambient noisenoise

Earmolds for Westone Earmolds for Westone UM1 and UM 2 earphonesUM1 and UM 2 earphones Requires custom Requires custom

earmolds to be earmolds to be taken by an taken by an AudiologistAudiologist

Thank you very muchThank you very much

You’ve been a great audience!You’ve been a great audience!