By: Mazen Al-Hakim, M.D.
SEIZURE MIMICS
Seizure Mimics
* A-clinical: -Syncope
-“Pseudo-seizures”
-Sleep disturbances
-Hyperventilation
-Metabolic
* B. EEG Misreading
Syncope
1- Convulsive Syncope
2- Eyes rolled back
3- Staring
4- Incontinence
Prodrome of Syncope
 Light-headed, blurred vision, pallor, sweating,
nausea…
Seizure Prodrome
 Aura=Focal seizure
Usually temporal: déjà vu
Jamais vu, rising sensation in abdomen,
abnormal smell or taste
Landmark Study of Syncope by
Lempert et al, 1994
-Myoclonus is common
-Head turning, automatism, hallucinations
• Postictal is the most important
• Syncope: No post-ictal encephalopathy
low blood pressure
• Seizure: Amnesia, confusion, lethargy,
agitation
High blood pressure, tongue biting
EEG in convulsive syncope
 Slow, then flat line
 No seizure
Pseudo seizures
 30% of referral to video monitor for
“intractable seizures”
Combination of Seizure and
Pseudo seizure is uncommon
 Underlying psychopathology and emotional
trauma including sexual abuse
Clinical signs
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Stop and go activity
Out of phase
Head turning right and left
Nonclonic shaking
Pelvic thrusting
Opisthotonic posturing
Vocalization: stuttering, weeping
Preserved awareness during bilateral motor activity
Ictal eye closure
Pseudosyncope
Postictal whispering
No postictal encephalopathy
 Another 30% patient referred for intractable
epilepsy had EEG misread as epileptic
The most common pattern is:
 Nonspecific fluctuations of background in the
temporal regions
Epileptic discharges
-clearly distinguished from background
-pointed peak
-spike: 20-70 msec.
-sharp wave: 70-200 msec.
Maulsby’s Guidelines, 1971
1- Artifact until proven otherwise
2- Electrical field
3- Negative polarity
4- Followed by slow wave
5- Ignore simple alterations in voltage, or
superimposed several components
6- Be familiar with “normal” sharp waves or
spikes
Normal alpha in an adult EEG with a phase reversal at the T6 electrode derivation that was identified as
“suspicious” for an epileptiform discharge (arrows)
with a phase reversal at the T6 electrode derivation that was identified as “suspicious” for an
epileptiform discharge (arrows).
Tatum W O Neurology 2013;80:S4-S11
© 2013 American Academy of Neurology
Normal EEG in an 18-year-old showing a hypnagogic (“drowsy”) burst (oval) of paroxysmal theta and
delta frequencies that appears sharply contouredThis reflects normal electrocerebral activity during
sleep transition. Note the change in the EEG immediately after the burst to reflect the change in state.
The “MARK” applied by the technologist signifies a “suspicious” burst.
ars sleep transition.
Tatum W O Neurology 2013;80:S4-S11
© 2013 American Academy of Neurology
Wicket spikes appearing in repetitive bursts during the awake state in a 57-year-old (circles)
bursts during the awake state in a 57-year-old (circles).
Tatum W O Neurology 2013;80:S4-S11
© 2013 American Academy of Neurology
Rhythmic midtemporal theta bursts of drowsiness in the EEG of a young
adultNote the sharply contoured waveform that mimics the appearance of
bilateral bursts of repetitive temporal sharp waves (boxes).
Tatum W O Neurology 2013;80:S4-S11
© 2013 American Academy of Neurology
Figure 8 Adult EEG demonstrating lambda waves during scanning eye movements (black
arrows)Although the pattern may appear morphologically as a “sharp wave,” the location,
positive polarity, and the relationship to scanning eye movements (reading) are distinctive.
Tatum W O Neurology 2013;80:S4-S11
© 2013 American Academy of Neurology