VEP - Sharon's Report
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Transcript of VEP - Sharon's Report
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8/7/2019 VEP - Sharon's Report
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VisuallyEvokedPoten2alreportby:SharonVaswani VEP
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WhatisaVisuallyEvokedPotenal
(VEP)?
AVEPisanevokedpoten.alcausedbyavisuals2mulus,suchasanalterna.ngcheckerboardpa9ernonacomputerscreen.Responsesarerecordedfromelectrodesthatareplacedonthebackofyourheadandareobservedasareadingonanelectroencephalogram(EEG)Theseresponsesusuallyoriginatefromtheoccipitalcortex,theareaofthebraininvolvedinreceivingandinterpre.ngvisualsignals
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WhenistheVEPused?
AdoctormayrecommendthatyougoforaVEPtestwhenyouareexperiencingchangesinyourvisionthatcanbeduetoproblemsalongthe
pathwaysofcertainnervesSomeofthesesymptomsmayinclude:
Lossofvision(thiscanbepainfulornon-painful);Doublevision;Blurredvision;Flashinglights;Altera.onsincolorvision;orWeaknessoftheeyes,armsorlegs
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WhenistheVEPused?
ThesechangesareoOentoosubtleornoteasilydetectedonclinicalexamina.oninthedoctor'ssurgeryIngeneralterms,thetestisusefulfor
detec.ngop2cnerveproblemsThisnervehelpstransfersignalstoallowustosee,sotes.ngthe
nerveallowsthedoctortoseehowyourvisualsystemrespondstolight
Thetestisalsousefulbecauseitcanbe
usedtocheckvisioninchildrenand
adultswhoareunabletoreadeyecharts
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WhatdoestheVEPdetect?
TheVEPmeasuresthe.methatittakesforavisuals.mulustotravelfromtheeyetotheoccipitalcortexItcangivethedoctor
anideaofwhetherthenervepathwaysareabnormalinanyway
Forexample,inmul.plesclerosis,theinsula.nglayeraround
nervecellsinthebrainandspinalcord(myelinsheath)canbe
affected
Thismeansthatittakeslonger.meforelectrical
signalstobeconductedtotheeyes,resul.nginabnormalVEPAnormalVEPissensi.vein
excludingalesionoftheop.cnerve,alongits
pathwaysintheanteriorpartofthebrain
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TheVEPisanimportantdiagnos.candprognos.ctoolforpredic.ngthe
developmentofvisioninprematureorsmallforgesta.onalageinfantswithgeneralized
delaysinmotordevelopment
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Whattheresultsofthetestmay
show...
TheVEPispar.cularlyusefulindetec.ngpastop2cneuri2s.Thisreferstoinflamma2onoftheop2cnerve,associatedwithswellingandprogressivedestruc.onofthesheathcovering
thenerve,andsome.mesthenervecableAsthenervesheathisdamaged,the.meittakesforelectricalsignalstobeconductedtotheeyesisprolonged,resul.nginanabnormalVEPThis
maybeseeninmul.plesclerosis-oneofthemostcommoncausesofop.cneuri.s(asabove)AbnormalVEP'sareseeninmul.plesclerosispa.entsduetothepresenceofop.cneuri.s
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Tumoursorlesionscompressingtheopcnerve-iftheop.cnerveiscompressed,thepathwayforconduc.onisaffectedandanabnormalVEPisseen
Glaucoma-pa.entswhosufferfromglaucomahaveincreasedintraocularpressure(iepressureinsidetheeye)Thiscanresult
indamagetotheop.cnerve,leadingtoprolongedVEPs Ocularhypertension(highpressure)-thisreferstoanysitua.on
inwhichthepressureintheeyeishigherthannormalThereare
nosignsofglaucoma,butpa.entsmaybeatincreasedriskof
developingglaucomalaterinlife
OpcNeuropathy-thiscanbeduetodamageoftheop.c
nervefromanumberofcauses,including:ablockageofthe
nerve'sbloodsupply,nutri.onaldeficiencies,ortoxinsAs
thenerveisdamaged,electricalsignalsdonotconductproperlyExamplesincludediabetes(advancedstages),toxic
amblyopia
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TheinfantsVAises.matedbydeterminingthe
smalleststripewidththats.mulates
preferen.alfixa.on
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