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

2. How is PNES Diagnosed with Video-EEG
September 20th, 2014
How is PNES Diagnosed
with Video-EEG

3. PNES
Non-epileptic seizures are episodes that resemble epileptic seizures clinically but are not derived from electrical disturbances.

4. 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).

5. 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. *

6. 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.

7. Electroencephalogram (EEG)

8. Electroencephalogram EEG
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.

9. 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?) 9

10. Electrodes

14. Inpatient Video-EEG

15. Outpatient Ambulatory Video-EEG

16. 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.

19. 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.

20. 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.

21. 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.

22. 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.

23. 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.

24. EEG (Seizure)

26. 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.

27. 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

28. 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

29. Video-EEG Monitoring Limitations
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).

30. 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%).