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AUDIOLOGY. Presented by Coleen Maritz Audiologist. 1. Anatomy of the ear. 2. Types of Hearing Loss. Conductive Hearing Loss -Resultant of outer or middle ear pathology. When the transmission of sound is interrupted in the outer ear ormore frequently in the middle ear. - PowerPoint PPT Presentation


  • Presented by Coleen MaritzAudiologist

  • 1. Anatomy of the ear

  • 2. Types of Hearing LossConductive Hearing Loss-Resultant of outer or middle ear pathology. When the transmission of sound is interrupted in the outer ear ormore frequently in the middle ear.-Children: most common cause is otits media. Adults: most common cause is otosclerosis.

  • Types of Hearing Loss Cont.Sensorineural Hearing Loss-Resultant of inner ear and/or auditory nerve damage.-When the hair cells of the cochlea or the acoustic nerve are damaged.

  • Types of Hearing Loss Cont.Mixed Hearing Loss-Involves a combination of a conductive and sensorineural hearing loss.

  • 3. Causes of Hearing LossCauses of Conductive Hearing Loss

    Outer and middle ear disorders may cause a conductive hearing loss.

  • Outer & Middle Ear Disorders

  • Outer & Middle Ear Disorders Cont

  • Outer & Middle Ear Disorders Cont

  • Outer & Middle Ear Disorders Cont

  • Outer & Middle Ear Disorders Cont

  • Causes of Hearing Loss Cont.Causes of Sensorineural Hearing Loss1. Prenatal Congenital infections* CMV viral infection; type of herpes virus transmitted in utero; can cause hearing loss, blindness and seizures* HIV affinity for CNS; opportunistic infections cause hearing loss eg. Meningitis* Rubella viral infection

  • Causes of Hearing Loss Cont.* Syphilis often causes progressive hearing loss; onset after 2 years of age* Toxoplasmosis caused by parasite infection transmitted through contaminated food; causes hydrocephalus, mental retardation and hearing loss

  • Causes of Hearing Loss Cont.2. Perinatal CausesHypoxiaBirth traumaHyperbilirubenemiaOtotoxic medicationPremature infants = increased risk for hearing loss

  • Causes of Hearing Loss Cont.3. Acquired hearing lossHerpes zoster oticus (Ramsay Hunt Syndrome) same virus that causes chickenpox; can cause hearing lossMumps acute systemic viral disease; common in childhood over the age of 2 years; often causes unilateral hearing lossMeaslesMeningitisSerous labyrinthitis (inflammation of labyrinth)

  • Causes of Hearing Loss Cont.Ototoxic medication:[Oto=ear. Ototoxic=Toxic to the ear]Ototoxic medications are drugs that have the potential to cause damage to the inner ear structures which may result in temporary or permanent hearing loss or an aggravation of an existing sensorineural hearing loss. Consuming more than one ototoxic medication at a time increases your risk to develop a sensorineural hearing loss.

  • Causes of Hearing Loss Cont.1. Aminoglycosides (antibiotics):AmikacinGentamycinGaramycinKanamycinNetilmycinTobramycinStreptomycinViomycinNeomycin

  • Causes of Hearing Loss Cont.Aminoglycosides (antibiotics) cont:These medications are toxic when used intravenously in serious life threathening situations. The blood levels of these medications are usually monitored to prevent ototoxicity. Topical preparations and ear drops containing these antibiotics, Neomycin, Gentamycin, have not been demonstrated to be toxic in humans.

  • Causes of Hearing Loss Cont.2. Erythromycin (antibiotics):



    New derivatives of Erythromycin

  • Causes of Hearing Loss Cont. Erythromycin (antibiotics) cont:

    These are usually ototoxic when given intravenously in dosages of 2-4 grams per 24hours, especially if there is underlying kidney insufficiency. The usual oral dosage of one gram per 24hours is not toxic. There are no significant reports of ototoxicity with new Erythromycin derivatives, since they are given orally at lower dosages.

  • Causes of Hearing Loss Cont.3. Vancomycin Vancocin (antibiotics)

    This antibiotic is used in a similar manner as the aminoglycosides; when given intravenously in serious life-threatening infections. It is potentially ototoxic. It is usually used together with the aminoglycosides which enhances the possibility of ototoxicity.

  • Causes of Hearing Loss Cont.4. Salicylates (used in treatment of arthritis):

    Toxic effects usually appear after consuming an average of 6-8 pills per day. Toxic effects are reversible once medication is discontinued. Acetylsalicylic acidAspirin

  • Causes of Hearing Loss Cont.5. Antimalarial medication-Quinine Derivitaves:

    Quinine ingestion can cause a syndrome including tinnitus, sensorineural hearing loss and vertigo. Recent studies suggest that quinine impairs outer hair cell mobility. Ototoxic effects are similar to asprin- reversible once medication is discontinued).

  • Causes of Hearing Loss Cont. Antimalarial medication-Quinine Derivitaves (cont.):

    Quinidex (causes tinnitus)AtrabrinePlaquenilQuinine SulfateMefloquineChloroquine

  • Causes of Hearing Loss Cont.6. Loop diuretics:

    These medications are usually ototoxic when given intravenously for acute kidney failure or acute hypertension. Rare cases have been reported when these medications are taken orally in high doses in people with chronic kidney disease. Edecrin (Ethacrynic acid)Lasix (Furosemide)Bumex (Bumetanide)

  • Causes of Hearing Loss Cont. 7. Chemotherapeutic Agents:

    CiaplatinNitrogen MustardVincristine

    These medications are ototoxic when given for treatment of cancer. The ototoxic effects of these medications are enhanced in patients who are already taking other ototoxic medications.

  • Causes of Hearing Loss Cont.8. Nonsteroidal Anti-Inflammatory Drugs Toxic effects usually appear after consuming an average of 6-8 pills per day. Toxic effects are usually reversible once medications are discontinued.

    AdvilMotrinAleveNalfonAnaproxNaprosynClinorilNuprinFeldenePoradolLodine Voltarin

  • Causes of Hearing Loss Cont.Acoustic trauma temporary or permanentMnires disease causes vertigo, hearing loss, tinnitus, pressure in ear; can be unilateral, fluctuating or progressivePresbyacusis age related sensorineural hearing lossNoise exposure- most common cause of HL.

  • Causes of Hearing Loss Cont.Noise Exposure- Damage risk criteria expressed as the maximum permissible noise exposure for a given duration during a work day.

  • Causes of Hearing Loss Cont.

    Syndromes associated with Auditory Dysfunction

    See handout

  • 4. Prevalence of hearing loss3/1000 infants are born with congenital severe bilateral hearing lossAdditional 3 children acquire hearing loss early in childhoodHearing loss occurs twice as frequently as other congenital abnormalities screened for in newborns combined: congenital hypothyroidism; sickle cell anemia; phenylketonuria; galactosemiaPrevalence = 10-20 times higher in NICU

  • Prevalence of hearing loss cont.Prevalence in general population:2/1000 = severe-profound HL5/1000 = moderate-severe HL8/1000 = mild HL150/1000 = middle ear infections

    Prevalence expected to be even higher with increase in HIV/AIDS infection

  • 5. Tinnitus1. Definition of tinnitus:hearing a sound that is not related to any external sound in the environmentRinging sound in patients ears is generated by patients own body, and is not present in external environmentMost common types of sounds reported by patients: ringing, hissing, buzzing, cricket sounds

  • Tinnitus cont.2. Neurophysiological model of Tinnitus Stages of tinnitus emergence: Generation- typically in the periphery Detection subcortical centers Perception and evaluation cotical areas Sustained activation of emotional (Limbic) and autonomic nervous systems

  • Tinnitus cont.3. Prevalence of tinnitus17% of general population (44million)Clinically significant problems for approximately 4-5% of the population

    4. Impact on patients livesRanges from mild irritation to total disability, and in some cases suicide

  • Tinnitus cont.5. CausesMay be associated with sensorineural hearing loss (damage to OHC and IHC)Ionic imbalance in the cochleaDysfunction of cochlear neurotransmitter systemsCentralCertain medication may cause tinnitus: eg. antidepressants, benzodiazeptinesUnknown causes in a lot of cases

  • Tinnitus cont.6. TreatmentUnable to suppress tinnitus source therefore do not currently have a cureTinnitus Retraining Therapy helps patients to adapt to noise, and to change their brains perception of the tinnitus; makes use of noise generators to mask tinnitusSuccess rate of 80%

  • 6. Hearing Tests1. AudiometryPuretone Speech2. Immittance Testing TympanometryAcoustic Reflexes3. Electrophysiological TestingOtoacoustic Emissions (OAE)Auditory Brainstem Response (ABR)

  • Hearing Tests cont.1. Audiometry1.1 What is audiometry & how does it work?2 measures: intensity & frequencyIntensity:Loudness, measured in dBHuman ear: 0-120 dBFrequency:Pitch/ tone of sound, measured in HzHuman ear: 20-20 000Hz; 125-8000 Hz

  • Hearing Tests cont.Air conduction audiometry:Earphones, outer ear, middle ear, inner ear, n. VIIIBone conduction audiometry:Bone conductor on mastoid

  • Hearing Tests cont.1.2 Aims of Audiometry:Measure degree of HL: minimal, mild, moderate, severe, profoundMeasure site of lesion in hearing mechanismDetermine cause of HLDetermine degree of handicap (how HL affects patients activities of daily life)

  • Hearing Tests cont.1.2 Aims of Audiometry cont:

    Obtain indications for appropriate therapeutic and educational assistance hearing aids; assistive listening devices; speech-language therapy; school placement

  • Degree of Hearing Loss

  • Environmental sounds measured on audiogram

  • What is an Aud


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