The Effects of Noise on Hearing How to Protect your Ears from Damage by Loud Sounds Carol Rousseau, M.A., CCC-A Clinical Audiologist Rochester Hearing and Speech Center Rochester, New York 5 March 2009

Goals for Presentation What is Noise? What is Noise? How we hear -- anatomy and physiology of the ear How we hear -- anatomy and physiology of the ear How noise effects the ear How noise effects the ear Discuss and demonstrate various types of Hearing Protection Devices (HPD) Discuss and demonstrate various types of Hearing Protection Devices (HPD)

What is Noise? Subjective Subjective Unpleasant or unwanted sound Unpleasant or unwanted sound It is a by-product of many industrial processes It is a by-product of many industrial processes

What is Noise? Exposure to high levels of noise can cause hearing loss as well as other health related issues Exposure to high levels of noise can cause hearing loss as well as other health related issues

Anatomy of the Ear Conductive Conductive –Outer Ear –Middle Ear Sensorineural Sensorineural –Inner Ear –Auditory Nerve Central Central –Brain

Anatomy and Physics of the Ear

What is Noise-Induced Hearing Loss? Caused by damage to the cochlea due to the over stimulation of the inner ear structures Caused by damage to the cochlea due to the over stimulation of the inner ear structures –Mechanical damage –Chemical damage

What is Noise-Induced Hearing Loss? Damage can occur in two ways Damage can occur in two ways –Sudden intense noise that can cause an acoustic trauma –Long-term exposure to intense noise

What is Noise-Induced Hearing Loss? Extent of damage depends on the intensity of noise and the duration of the exposure Extent of damage depends on the intensity of noise and the duration of the exposure –Noise louder than 85 db can cause damage –Risk of hearing loss from noise doubles with each 3 dB increase in sound level

Decibel Exposure Time Guidelines

Audiogram Noise-Induced Hearing Loss

Healthy and Damaged Hair Cells

Physiologic Effects on the Cochlea Loss of hearing sensitivity Loss of hearing sensitivity –Especially in the High Frequencies Loss of clarity Loss of clarity Decreased sound localization Decreased sound localization Reduced tolerance to loud sounds Reduced tolerance to loud sounds

Other Physiological Effects Tinnitus Tinnitus Cardiovascular Cardiovascular Mental Health Mental Health

Noise Combined with Chemical Agents Some substances may be more dangerous when combined with noise exposure Some substances may be more dangerous when combined with noise exposure –Aspirin –Some antibiotics and chemotherapy drugs –Industrial chemicals such as lead, styrene, carbon dioxide, and carbon disulfide

Damage can either be Temporary or Permanent Temporary Threshold Shift (TTS) it a temporary elevation of the hearing threshold at one or more frequencies Temporary Threshold Shift (TTS) it a temporary elevation of the hearing threshold at one or more frequencies –Short-term exposure to noise –Comes back after a period of rest Permanent Threshold Shift (PTS) is a permanent elevation caused by damage to the hair cells, which can not be regenerated once they are injured Permanent Threshold Shift (PTS) is a permanent elevation caused by damage to the hair cells, which can not be regenerated once they are injured –Prolonged exposure to high noise levels over a period of time –Gradually causes permanent damage

Hearing Protection Devices Occupational Occupational Recreational Recreational

Occupations Who May Need HPD Industrial Workers Industrial Workers Construction Construction Military Military Musicians and Other Entertainment Professionals Musicians and Other Entertainment Professionals Farmers Farmers Day Care Workers Day Care Workers Dentists Dentists Pediatricians Pediatricians Nurses Nurses

Recreational Activities Music Music –Stereo and Personal Listening Devices (iPods) –Concerts –Performing Hunting and Target Shooting Hunting and Target Shooting Motorcycling Motorcycling Drag Races and NASCAR Drag Races and NASCAR Snowmobiling Snowmobiling Woodwork Woodwork Lawnwork Lawnwork

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

Types of HPD Ear Plugs Ear Plugs Ear Filters Ear Filters Ear Muffs Ear Muffs Semi-Aural Protectors Semi-Aural Protectors Custom Ear Molds Custom Ear Molds In-the-Ear Monitors In-the-Ear Monitors

Ear Plugs Generally made of soft polyurethane or silicone foam, wax Generally made of soft polyurethane or silicone foam, wax One Size Fits All One Size Fits All Inserted into Ear Canal Inserted into Ear Canal Disposable Disposable Attenuates dB Attenuates dB Reduces high frequencies more than low, giving a muffled sound Reduces high frequencies more than low, giving a muffled sound

Non-custom Foam Ear Plugs 29db of attenuation 29db of attenuation

Pre-molded Ear Plugs Made of vinyl, silicone or rubber Made of vinyl, silicone or rubber Come in different sizes for fitting Come in different sizes for fitting Re-usable Re-usable

Ear Seals Soft flanged ear seals Soft flanged ear seals Detachable cord Detachable cord

Ear Filters Attenuates sound more evenly through baffles or moving diaphragms Attenuates sound more evenly through baffles or moving diaphragms One size fits all One size fits all

Non-custom Musicians’ Earplugs ER-20 ER-20 Attenuates sound more evenly through baffles or moving diaphragms Attenuates sound more evenly through baffles or moving diaphragms No custom mold needed No custom mold needed

Ear Muffs Circum-aural protectors Circum-aural protectors Adjustable Adjustable

Semi-Aural Protectors Ear plugs tips connected to a headband Ear plugs tips connected to a headband Usually one size fits all Usually one size fits all Can be taken on/off quickly Can be taken on/off quickly Attenuation less than that of other HPDs Attenuation less than that of other HPDs

Custom-made Ear Molds General purpose solid ear plugs General purpose solid ear plugs Custom molded for the individual Custom molded for the individual Reusable Reusable

Industrial Ear Plugs Custom molded ear plugs Custom molded ear plugs Attenuates approximately 29 dB Attenuates approximately 29 dB

Hunters Ear Plugs Pressure valve for occasional high impact noise Pressure valve for occasional high impact noise Allows normal hearing until a gun shot activates the valve Allows normal hearing until a gun shot activates the valve

Motorcycle Ear Plug Canal style Canal style Comfort while wearing under a helmet Comfort while wearing under a helmet Also for sleeping Also for sleeping

Swim Plugs For swimmers For swimmers Kid with PE tubes Kid with PE tubes

Exposure Ear Plugs Keeps out the environment but allows for communication Keeps out the environment but allows for communication For surfers, dude For surfers, dude

Custom Musician Ear Plugs a special filter allows the listener to hear music at a safe level without sacrificing sound quality a special filter allows the listener to hear music at a safe level without sacrificing sound quality Instead of cutting out the high frequencies, musician's plugs attenuate all the frequencies evenly in relation to your hearing. Instead of cutting out the high frequencies, musician's plugs attenuate all the frequencies evenly in relation to your hearing. Custom plugs come in ER-9, ER-15 or ER-25 filters Custom plugs come in ER-9, ER-15 or ER-25 filters An audiologist or other hearing health professional takes impressions of the ear canal. An audiologist or other hearing health professional takes impressions of the ear canal.

In-the-Ear Monitors Provide up to 25 dB of attenuation from ambient noise Provide up to 25 dB of attenuation from ambient noise

Earmolds for Westone UM1 and UM 2 earphones Requires custom earmolds to be taken by an Audiologist Requires custom earmolds to be taken by an Audiologist

Thank you very much You’ve been a great audience!