Northeast Regional Epilepsy Group Christos Lambrakis M.D. 1.

Northeast Regional Epilepsy Group

Christos Lambrakis M.D.

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September 20th, 2014

How is PNES Diagnosed

with Video-EEG

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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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• 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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• 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

Electroencephalogram (EEG)

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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?)

Electrodes

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Inpatient Video-EEG

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Outpatient Ambulatory Video-EEG

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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.


• 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 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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• 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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EEG (Seizure)

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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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• 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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• 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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• ~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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Northeast Regional Epilepsy Group Christos Lambrakis M.D. 1.

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