34015-56111-082 BRO How We Hear.indd 1 The InnerEar CAUSES OFHEARINGLOSS • • • • FACTS The MiddleEar The OuterEar the morecommoncauses. There aremanyconditionsthatcancausehearingloss.Thefollowingsomeof 15% currently usehearing aidswithbenefit. 15% currently 15-20% maybenefitfromaprocedure toimprovetheirhearing. 25 millionpeopleintheUnited States sufferfromahearingloss. 500 millionpeopleintheworld sufferfromahearingloss. 7. Rarely, braintumors maydamagethehearingnerve. 6. Injuriestotheheadthatdamageinnerear, orbrain. hearingnerve highfevers. 5. Illnesswithvery hearing loss. 4. Congenitalorhereditary 3. Gradualexposureovermonthsoryearstodamaging,butlessintense loudsoundssuchasthefiringofa 2. Suddenorprolongedexposuretovery 1. Theagingprocessmaycauseagradualdeclineinhearing.Thisisknown 6. Improperdevelopmentorfixationofthemiddleearbones. 5. Injuriestotheheadthatdamageordisconnectmiddleearbones. 4. Otosclerosis:Thisconditionpreventsmovementofthestapesbone.Itis 3. Cyst(cholesteatoma)blockingmovementoftheearbones. 2. oftheeardrum. 1. Aholeorperforation orstenosis,ofthe earcanal. 4. Narrowing, 3. Foreignbody. otitisor“swimmer’s2. Infection(external ear”):Thiscancauseswelling, buildup). 1. Earwax(cerumen sounds such as factory noise, or continued use of portable radios. noise,orcontinueduseofportable sounds suchasfactory music. gun, orexposureto“rock”concert as presbycusis. caused byexcessivebonegrowtharoundthestapes. Infection ofthemiddleear(otitismedia)causingfluidbuildup. pain, itchingandrawnessoftheearcanal. The MiddleEar 34015-56111-082 (5/23/14) hearing loss. which is a combination of mixed both hearing a impairment, conductive and sensorineural and exist:conductive,sensorineural(“nerve”), Three typesofhearingimpairments inthe2000s!) treatmentplanssimplyarenottrue many oftheoldermythsconcerning ahearingevaluation(audiogram).(Remember, byperforming may thenbedetermined thecauseofhearingloss.Thetypeloss physician inordertodetermine the typeofhearingloss.Treatment beginswithathoroughphysicalexaminationby dependsonknowledgeofboththecauseand The treatmentofhearingimpairment TREATMENT OFHEARINGIMPAIRMENT The OuterEar the morecommoncausesofconductivehearinglosswithtreatmentoptions. This typeoflossisduetoanouterearormiddleproblem.Thefollowinga list of Conductive HearingLoss (vestibular) nerve asanelectricalimpulseandareinterpreted asthesensationofmotion. (vestibular) nerve in thebalancechamber. Thesemovements aresenttothebrainalong balance and back,causemovementoffluid Head movements,eithersideto or forward BALANCE the hearingloss. loss. Treatment of depends ontheseverityofconductiveandsensorineuralportions This typeofhearinglossisacombinationconductiveandsensorineural hearing Mixed HearingLoss oftheinnerearandelectronicallystimulateshearingnerve. bypasses damagedparts cochlear implantisanelectronicdevicesurgicallyimplantedintotheinnerear. It In personswhoaretotallydeaf,acochlearimplantispossibletreatmentoption.A hearinglossisbesttreated withahearingaid. “nerve” problem.Sensorineuralor This typeoflossisduetoaninnerearorhearingnerve HearingLoss Sensorineural or“Nerve” 5. Injuriestotheheadwhichdamageordisconnectmiddleearbone(s) 4. Otosclerosis(Surgicalplacementofthestapesbonewithaprosthesisand/or 3. Cystorcholesteatoma(Surgicalremoval). 2. OtitisMedia(Antibioticorplacementofasmalltubeintheeardrum). (Surgicalrepair). ofeardrum 1. Aholeorperforation 3. otitisor“swimmer’s2. External ear”(Antibioticeardrop). 1. Earwax (Replacement oftheearbone(s)withaprosthesis. use ahearingaid). defectoftheearcanal(Surgicalwideningcanal). A birth (Removal byaphysician). - FacialNerve - Balance - Hearing How We Hear Michigan Ear Institute www.michiganear.com 248-865-4444 12/1/16 10:17 AM NORMAL EAR ANATOMY HOW THE EAR WORKS
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Outer Ear 4 Inner Ear Middle Ear 9 1 Eardrum 4 Stapes 7 Vestibular Nerve 1 Sound waves enter 2 Malleus 5 Semicircular Canals 8 Endolymphatic Sac the ear through the 3 Incus 6 Cochlear Nerve 9 Eustachian Tube external auditory canal. 6 Movement of membranes Structure and Function of the Ear cause tiny hair cells to bend and transmit impulses to The ear consists of three main parts: the outer, the middle ear, and the the cochlear nerve, and then inner ear. 2 Sound waves strike to the brain. The Outer Ear the eardrum, causing it to vibrate. The outer ear consists of the portion that is visible, plus the ear canal. At 3Vibrations are 5Fluid pushes against the end of the ear canal is a tightly stretched membrane, the eardrum. transmitted to membranes within The eardrum separates the outer ear from the middle ear. the malleus, incus, 4 The stapes moves in and the cochlea. The Middle Ear and stapes. out of the oval window, The middle ear consists of the space behind the eardrum and is continuous producing waves in the with the eustachian tube and the mastoid air cells. Three small bones fluid that fills the cochlea. called the malleus, the incus and the stapes connect the eardrum to the inner ear. The Inner Ear The inner ear is encased in bone and consists of the cochlea, which is for Hearing is a principal tool for communication with all those around us. In children, hearing is essential for speech and language development. At any age, the hearing, and the semicircular canals, which are for balance. The organs ability to hear can be a source of pleasure and enjoyment. within the ear are bathed in fluid and contain the delicate nerve endings of This booklet is designed to provide the reader with an understanding of the function of the ear, and discuss treatment options of the more common causes of balance and hearing. hearing loss. It is hoped that, through understanding, those with a hearing impairment will realize that hearing loss is a problem that can be solved.
34015-56111-082 BRO How We Hear.indd 2 12/1/16 10:17 AM