ConductivehearinglossDuetointerferenceofconductionofsoundtoreachthecochleaFeature:Rinnetest-usuallynegative(BC>AC)Webertest-lateralizedtoworseearABCtest-normalLowfrequenciesmoreaffectedPuretoneaudiogram-BC>ACABgap>10dBHLnotusually>60dBSpeechdiscriminationisgood6
6 Conductive hearing loss ⚫ Due to interference of conduction of sound to reach the cochlea ⚫ Feature : Rinne test – usually negative (BC > AC) Weber test- lateralized to worse ear ABC test – normal Low frequencies more affected Pure tone audiogram – BC > AC AB gap > 10dB HL not usually > 60dB Speech discrimination is good
Congenital Causesof CHLanotiameatal atresiafixation -foot plate,malleus headossiculardiscontinuitycongenital cholesteatoma
7 Congenital Causes of CHL anotia meatal atresia fixation – foot plate, malleus head ossicular discontinuity congenital cholesteatoma
AcquiredcausesofCHLObstructionof EAC:wax,FB,furuncle,tumourTympanicmembrane-perforationMiddleear-fluid-OME.blood-infection-CSOM,AOM-tumourOssiclesdisruption-trauma,infectionfixation - otospongiosistympanosclerosisEustachiantube block8
8 Acquired causes of CHL ⚫ Obstruction of EAC : wax,FB,furuncle,tumour ⚫ Tympanic membrane – perforation ⚫ Middle ear – fluid – OME, blood - infection –CSOM, AOM - tumour ⚫ Ossicles disruption – trauma, infection fixation - otospongiosis tympanosclerosis ⚫ Eustachian tube block
atresia in the external canal
9 atresia in the external canal
CommoncausesofCHLOtitismedia-CSOM.AOM.OMETympanosclerosisTraumaticperforation of TM,barotraumaOtospongiosisImpactedwax10
10 Common causes of CHL ⚫ Otitis media – CSOM,AOM,OME ⚫ Tympanosclerosis ⚫ Traumatic perforation of TM, barotrauma ⚫ Otospongiosis ⚫ Impacted wax