Benign epileptiform variants in EEG

8/11/2019 Benign epileptiform variants in EEG

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Benign

epileptiform

variants

Seyed

M

Mirsattari,

MD,

PhD,

FRCPC

DepartmentsofClinicalNeurological

Sciences,MedicalBiophysics,Diagnostic

Imaging,Psychology

University

of

Western

Ontario

London,Ontario

EEGCourse,CNSF,QuebecCity,QE

Friday

June

11,

2010


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LearningObjectives

TodefineBenignEpileptiformVariants

(BEVs)

TobeabletoclassifyBEVsintobroad

major

categories

To

know

the

prevalence

of

BEVs


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DisclosureStatement

Dr.Mirsattarihasnothingtodisclose.


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Definition

of

a

Benign

Epileptiform

Variant

in

the

EEG

EEGpatternthatismorphologically

epileptiformbutisnotassociatedwith

epilepsy.


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Significance

of

correctly

identifying

the

BEVs

in

the

EEGToavoidmisdiagnosisofthesubjectswithepilepsy

based

on

these

waveforms

Toavoidunnecessarytreatmentsofthesesubjects

withanti-epilepticdrugsorepilepsysurgery.

Toavoidothernegativeimpactofepilepsyonthe

livesoftheseindividuals,e.g.driving


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International10-20systemof

electrode

placements

JasperHH.Theten-twentyelectrodesystemoftheInternationalFederation.

Electroenceph

Clin

Neurophysiol

1958;10:371-

5.


7/37

EEGmontages

Bipolar Coronal

Common

AverageReference

Point=

CAR

Referential


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EEG

scalp

recording:

normal,

awake


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Classification

of

BEVs

Twomajorcategories

Sharply

contoured

BEVs:Wicketwaves

Benignsporadicsleepspikes(BSSS)

BEVs

occurring

in

bursts

or

trains:6Hzspike-waves

14&6Hzpositivespikes

Rhythmictemporalthetaburstsofdrowsiness

(RTTD)

Subclinicalrhythmicelectrographicdischargeof

adults(SREDA)

To

know

the

prevalence

of

BEVs


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SharplycontouredBEVs

Wicketwaves



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Wicketwaves

Arciform,

resembles

Greek

letter

Negative

phase

apiculate

Positivephaserounded

Single

or

clusters

T3,4orT3,4&F7,8

Noafter-comingslowwave

Nodistortionofbackgroundrhythms

in

drowsiness

or

sleep

Unilateral

or

independent

bilateral


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Wicketwaves

Santoshkumaretal.ClinNeurophysiol2009;120:856-61.


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SharplycontouredBEVs

Wicketwaves


a.k.asmal

l

sharp

spikes

(SSS)


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BenignSporadicSleepSpikesBETSBenignEpileptiformTransientsofSleep

Abruptascendingslope

Steeperdescendingslope

Usuallyshortduration


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Benign

Sporadic

Sleep

SpikesBETSBenignEpileptiformTransientsofSleep



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BEVs

occurring

in

bursts

or

trains 6Hzspike-waves


Rhythmictemporalthetaburstsofdrowsiness

(RTTD)

Subclinicalrhythmicelectrographicdischargeof

adults(SREDA)


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6persecondspike-waves

(PhantomSpikeandWave)

57Hz

Brieflowamplitudespike

Slow

wave

has

wider

field

than

spike

Adolescents

and

adults

Awake,

drowsiness,

not

sleep

Bisynchronous


18/37

6HzSW(cont.)

FOLD

Female

Occipitally-predominant

Low-

amplitudeDrowsiness

WHAMWakeHigh-amplitudeAnteriorMale

FOLDappearancemorebenign

WHAM

appearance

more

suggestive

of

underlying

generalized

seizure

disorder

Benign

6

Hz

SW

should

disappear

in

sleep,

whereaspathologicalSWisoftenenhanced

b slee

6 H SW ( t )


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6

Hz

SW

(cont.)



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Positive

component

apiculate

or

arciform

Negativecomponentsmooth

13-17Hzor6-7Hz;principally14or6Hz

Drowsiness

and

light

sleep

Posteriortemporalandadjacentareas

Widespread

fieldBestrecorded:coronalorreferential

montages

Adolescents, young adults


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CorticalLocationofBenignParoxysmal

RhythmsintheElectrocorticogram

6

Hz

SW(8/61)

oBETS(3/61)

o14&6

Hz

positive

spikes(4/61)

McLachlan

RS,

Luba

N.

Can

J

Neurol

Sci

2002;29:154-158


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RhythmicTemporalThetaofDrowsiness

(PsychomotorVariant)

5-7

HzSharplycontoured,oftennotched

Mid-anteriortemporalregions

Parasagittalspread

Burstsorruns

Bilateralorindependenteithersideorshifting

emphasissidetoside

Can

have

a

gradual

onset

and

offset

Monomorphic (noevolution)

Duringrelaxedwakefulnessanddrowsiness

Mainly

adolescent

and

adults

f


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RhythmicTemporalThetaofDrowsiness

(Psychomotor

Variant)


Subclinical Rhythmic Electrographic


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Subclinical

Rhythmic

Electrographic

DischargeofAdults (SREDA)

Sequential

monophasic

or

biphasic

apiculate

wavesmixedwithrhythmicthetaordelta

Noevolution

Abrupt

onset

and

gradual

offsetUsually

in

wakefulness,

occasionally

in

sleep

May

occur

during

HV

Principally

parietal,

posterior

temporal

Bisynchronous

or

unilateral

Duration~20secto a few minutes

Occurs elderly ormiddle age


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SREDA



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SREDA

First

described

by

Westmoreland

BF

and

KlassDW(1981)

65

patients

(37

F;

28

M)

between

1959

&

1978

Meanage61years(42-80years)

Non-evolvingrhythm

Widespread,maximalovertheP-postT

Duration:fewsecondstoaminute

-

Unusual variants of SREDA


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Unusual

variants

of

SREDAStudyinterval=1959-1995N=108patients(191EEGs)

49

Males;

59

FemalesMeanage=62years(range=35-89years)Prevalence=1/2500recordings89withtypicalSREDApatternUnusualvariants(19/108) 10

Males;

9

Females meanage61(range=35-89years) Predominantfrequencies Frontalormorefocaldistribution

Notched

waveforms Longerduration Atypicalevolution Presenceinyoungerindividuals Occurrenceinsleep

WestmorelandBFandKlassDW.ElectroencephClinNeurophysiol1997;102:1-4.

Decharges paroxystiques


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Decharges

paroxystiques

Naquetetal.1961

Paroxysmal

discharges

of

the

parieto-

temporo-occipitaljunction

Reliablyinducedby:

HVpurerelativehypoxiaassociated

withnitrogeninhalation

Mildrelativeischemiafromcarotid

artery

compression

Postulatedthatitwasassociatedwith

cerebrovasculardisease

Naquet

R

et

al.,

Rev

Neurol

1961;105:203-7.Na uetRetal. ZentralblNeurochir1965 25:153-80.


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SREDAinChildren

Case

report

N=2

11

YO

F

presenting

with

HUS

10

YO

F

with

learning

difficulties

and

HA

Nagarajan

L,

et

al.

Pediatr

Neurol

2001;24:313-6.


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SREDAinREMsleep

Casereport

48

YO

M

CAD,

high

Chol,

HTN,

Obstructive

sleep

apnea

Fleming

WE,

et

al.

Sleep

Medicine

2004;5:77-81.


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SREDA

and

acute

brain

insults

4/340

patients

Syncope

TGA

GTC

RTLE

Begum

T,

et

al.

Internal

Medicine

2005;45:141-4.


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Parietal lobe source localization


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Parietal

lobe

source

localization

in

a

patient

with

SREDA

Zumsteg

D,

et

al.,

Clin

Neuophysiol

2006;

117:2257-63.

P l f b i il tif i t


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Prevalence

of

benign

epileptiform

variants

observedinanEEGlaboratoryfromCanada

Santoshkumar

et

al.

Clin

Neurophysiology

2009;120:856-61.

P l & D hi


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Prevalence&Demographics


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Conclusions

TheprevalenceofBEVsamongCanadiansubjectsis

nottoodifferentfromthosereportedfromother

developedcountries.

Theirmerepresenceinarecorddoesnotjustifythe

diagnosisofepilepsyortheinstitutionof

anticonvulsant

therapy.

Suitablecandidatesshouldnotbedeniedepilepsy

surgeryduetothemisinterpretationofthesebenign

variants.

Documents

Benign epileptiform variants in EEG