8/11/2019 Benign epileptiform variants in EEG
1/37
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
8/11/2019 Benign epileptiform variants in EEG
2/37
LearningObjectives
TodefineBenignEpileptiformVariants
(BEVs)
TobeabletoclassifyBEVsintobroad
major
categories
To
know
the
prevalence
of
BEVs
8/11/2019 Benign epileptiform variants in EEG
3/37
DisclosureStatement
Dr.Mirsattarihasnothingtodisclose.
8/11/2019 Benign epileptiform variants in EEG
4/37
Definition
of
a
Benign
Epileptiform
Variant
in
the
EEG
EEGpatternthatismorphologically
epileptiformbutisnotassociatedwith
epilepsy.
8/11/2019 Benign epileptiform variants in EEG
5/37
Significance
of
correctly
identifying
the
BEVs
in
the
EEGToavoidmisdiagnosisofthesubjectswithepilepsy
based
on
these
waveforms
Toavoidunnecessarytreatmentsofthesesubjects
withanti-epilepticdrugsorepilepsysurgery.
Toavoidothernegativeimpactofepilepsyonthe
livesoftheseindividuals,e.g.driving
8/11/2019 Benign epileptiform variants in EEG
6/37
International10-20systemof
electrode
placements
JasperHH.Theten-twentyelectrodesystemoftheInternationalFederation.
Electroenceph
Clin
Neurophysiol
1958;10:371-
5.
8/11/2019 Benign epileptiform variants in EEG
7/37
EEGmontages
Bipolar Coronal
Common
AverageReference
Point=
CAR
Referential
8/11/2019 Benign epileptiform variants in EEG
8/37
EEG
scalp
recording:
normal,
awake
8/11/2019 Benign epileptiform variants in EEG
9/37
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
8/11/2019 Benign epileptiform variants in EEG
10/37
SharplycontouredBEVs
Wicketwaves
Benignsporadicsleepspikes(BSSS)
8/11/2019 Benign epileptiform variants in EEG
11/37
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
8/11/2019 Benign epileptiform variants in EEG
12/37
Wicketwaves
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
8/11/2019 Benign epileptiform variants in EEG
13/37
SharplycontouredBEVs
Wicketwaves
Benignsporadicsleepspikes(BSSS)
a.k.asmal
l
sharp
spikes
(SSS)
8/11/2019 Benign epileptiform variants in EEG
14/37
BenignSporadicSleepSpikesBETSBenignEpileptiformTransientsofSleep
Abruptascendingslope
Steeperdescendingslope
Usuallyshortduration
8/11/2019 Benign epileptiform variants in EEG
15/37
Benign
Sporadic
Sleep
SpikesBETSBenignEpileptiformTransientsofSleep
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
8/11/2019 Benign epileptiform variants in EEG
16/37
BEVs
occurring
in
bursts
or
trains 6Hzspike-waves
14&6Hzpositivespikes
Rhythmictemporalthetaburstsofdrowsiness
(RTTD)
Subclinicalrhythmicelectrographicdischargeof
adults(SREDA)
8/11/2019 Benign epileptiform variants in EEG
17/37
6persecondspike-waves
(PhantomSpikeandWave)
57Hz
Brieflowamplitudespike
Slow
wave
has
wider
field
than
spike
Adolescents
and
adults
Awake,
drowsiness,
not
sleep
Bisynchronous
8/11/2019 Benign epileptiform variants in EEG
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 )
8/11/2019 Benign epileptiform variants in EEG
19/37
6
Hz
SW
(cont.)
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
8/11/2019 Benign epileptiform variants in EEG
20/37
14&6Hzpositivespikes
Positive
component
apiculate
or
arciform
Negativecomponentsmooth
13-17Hzor6-7Hz;principally14or6Hz
Drowsiness
and
light
sleep
Posteriortemporalandadjacentareas
Widespread
fieldBestrecorded:coronalorreferential
montages
Adolescents, young adults
8/11/2019 Benign epileptiform variants in EEG
21/37
14&6Hzpositivespikes
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
8/11/2019 Benign epileptiform variants in EEG
22/37
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
8/11/2019 Benign epileptiform variants in EEG
23/37
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
8/11/2019 Benign epileptiform variants in EEG
24/37
RhythmicTemporalThetaofDrowsiness
(Psychomotor
Variant)
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
Subclinical Rhythmic Electrographic
8/11/2019 Benign epileptiform variants in EEG
25/37
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
8/11/2019 Benign epileptiform variants in EEG
26/37
SREDA
Santoshkumaretal.ClinNeurophysiol2009;120:856-61.
8/11/2019 Benign epileptiform variants in EEG
27/37
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
8/11/2019 Benign epileptiform variants in EEG
28/37
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
8/11/2019 Benign epileptiform variants in EEG
29/37
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.
8/11/2019 Benign epileptiform variants in EEG
30/37
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.
8/11/2019 Benign epileptiform variants in EEG
31/37
SREDAinREMsleep
Casereport
48
YO
M
CAD,
high
Chol,
HTN,
Obstructive
sleep
apnea
Fleming
WE,
et
al.
Sleep
Medicine
2004;5:77-81.
8/11/2019 Benign epileptiform variants in EEG
32/37
SREDA
and
acute
brain
insults
4/340
patients
Syncope
TGA
GTC
RTLE
Begum
T,
et
al.
Internal
Medicine
2005;45:141-4.
8/11/2019 Benign epileptiform variants in EEG
33/37
Parietal lobe source localization
8/11/2019 Benign epileptiform variants in EEG
34/37
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
8/11/2019 Benign epileptiform variants in EEG
35/37
Prevalence
of
benign
epileptiform
variants
observedinanEEGlaboratoryfromCanada
Santoshkumar
et
al.
Clin
Neurophysiology
2009;120:856-61.
P l & D hi
8/11/2019 Benign epileptiform variants in EEG
36/37
Prevalence&Demographics
8/11/2019 Benign epileptiform variants in EEG
37/37
Conclusions
TheprevalenceofBEVsamongCanadiansubjectsis
nottoodifferentfromthosereportedfromother
developedcountries.
Theirmerepresenceinarecorddoesnotjustifythe
diagnosisofepilepsyortheinstitutionof
anticonvulsant
therapy.
Suitablecandidatesshouldnotbedeniedepilepsy
surgeryduetothemisinterpretationofthesebenign
variants.