Northeast Regional Epilepsy Group Christos Lambrakis M.D. 1
Dec 16, 2015
PNES
• Non-epileptic seizures are episodes that resemble epileptic seizures clinically but are not derived from electrical disturbances.
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Psychogenic Non-epileptic Seizures
• Resemble epileptic seizures but lack EEG correlate.
• Very common (~25% of patients referred to Video-EEG monitoring for evaluation of intractable epilepsy).
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Psychogenic Non-epileptic Seizures
• Psychiatric manifestation– Somatoform/Conversion Disorder (most common)
• Unconscious production of physical symptoms due to psychological factors
– Factitious Disorder• Consciously determined symptoms driven by a powerful
unconsciously determined need.
– Malingering• Willful production of symptoms for a specific external
incentive.
*
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Psychogenic Non-epileptic Seizures
• Often difficult to distinguish clinically from epileptic seizures.
• Clues: – Resistance to AEDs– Emotional Triggers (stress)– Bilateral clonic movements without loss of
consciousness– Absence of post-event confusion/lethargy.
• Video-EEG is very helpful in diagnosis. 6
ElectroencephalogramEEG
• Represents a record of the small shifting brain electrical potentials from the surface of the brain recorded over the scalp.
• As seizures are caused by a disturbance of electrical activity, the EEG is uniquely suited to further our understanding of a patients seizures.
Goals of Video-EEG Monitoring
• Is it really an epileptic seizure? (Epilepsy vs. non-epileptic events)
• What type of seizure is it? (Characterize epilepsy type)
• Where does the seizure originate from? Is it focal? (i.e. does it come from one specific region?)
Routine EEG• Short duration (<1 hour)• Low sensitivity. Events are seldom recorded.• Presence of inter-ictal baseline epileptogenic
abnormalities does not confirm or exclude either diagnosis.– Patient with inter-ictal epileptogenic
abnormalities can still have PNES.– Patient with normal inter-ictal EEG can still
have epilepsy.
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Video-EEG Monitoring
• Long term inpatient monitoring allows for recording of seizure events.
• Clinical and electroencephalographic features can be reviewed aiding in seizure characterization and localization.
• Baseline EEG may be helpful in determining risk of future seizures.
Video-EEG Monitoring
• Gold standard for differentiating PNES from ES.
• Recommended for patients with recurrent episodes despite multiple medication trials.
• Goal is to record typical event and document lack of EEG correlate.
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Video-EEG Monitoring
• Video component can be helpful in documenting movements or behaviors typically incompatible with ES.
• Important in verifying that event recorded is representative of events which prompted medical attention.– ** ~20% of patients with PNES also have ES.
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Psychogenic Non-epileptic Seizures
• Many clinical patterns:– Migratory motor activity (most common)– Generalized motor activity– Unilateral (less common)– Alteration of awareness (Common)
** Can be difficult to distinguish from frontal lobe seizures.
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Non-epileptic Seizures
• EEG during PNES can be difficult to interpret.
• Movements during an PNES event cause rhythmic artifacts on EEG that look very similar to epileptic seizure activity.
• Some epileptic seizures (partial) can be electrically silent on EEG and can be misdiagnosed as PNES.
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Non-epileptic Seizures
• Analysis of the clinical semiology of the episodes thru video can be helpful in differentiation between PNES and ES.
– ** Definitive diagnosis should not rest solely on clinical observation. Certain types of epileptic seizures (frontal and temporal) can look very similar to a PNES event.
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Psychogenic Non-epileptic Seizures
• Characteristics of PNES– Variable responsiveness or preserved awareness.– Out of phase movements of extremities.– Discontinuous motor activity– Pelvic thrusting.– Side to side head movements. – Eye closure/eye flutter
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Psychogenic Non-epileptic Seizures
• Characteristics of PNES– Varied character of events– Suggestibility– Emotional triggers– Prompt recovery (Absence of post-ictal state)– Poor response to anti-epileptic medications
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Video-EEG MonitoringLimitations
• Event may not occur (consider home ambulatory Video-EEG).
• Missed PNES diagnosis (EEG over interpreted as ES due to rhythmic artifact).
• Incorrect PNES diagnosis (Partial ES may not display electrical abnormalities).
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Psychogenic Non-epileptic Seizures
• ~20 % of patients with PNES will also have coexistent epileptic seizures.
• Latency between manifestation of PNES and diagnosis is ~ 7years.
• Prompt diagnosis is crucial to avoid iatrogenic morbidity (Exposure to unnecessary medication ~80%, Intubation ~50%).
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