eMedicine Specialties > Neurology > Seizures and Epilepsy

Psychogenic Nonepileptic Seizures: Differential Diagnoses & Workup

Author: Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Contributor Information and Disclosures

Updated: Feb 18, 2010

Differential Diagnoses

Absence Seizures
Epilepsy, Juvenile Myoclonic
Ambulatory Electroencephalography (EEG)
Epileptiform Discharges
Brainstem Gliomas
First Seizure in Adulthood: Diagnosis and Treatment
Complex Partial Seizures
First Seizure: Pediatric Perspective
Dizziness, Vertigo, and Imbalance
Focal EEG Waveform Abnormalities
Driving and Neurological Disease
Frontal Lobe Epilepsy
EEG Seizure Monitoring
Myasthenia Gravis
Epilepsia Partialis Continua
Status Epilepticus
Epilepsy in Adults with Mental Retardation
Epilepsy in Children with Mental Retardation

Other Problems to Be Considered

Epileptic seizures: This is main differential diagnosis. However, proving a nonepileptic origin is not synonymous with proving a psychogenic origin. For information on epilepsy, see Medscape's Epilepsy Resource Center.

Other organic diseases that cause paroxysmal neurological symptoms: These other diseases must be considered in the differential diagnosis. Examples of organic (ie, nonpsychogenic), nonepileptic paroxysmal symptoms are syncope, migraine, cataplexy, and TIAs.

Workup

Laboratory Studies

  • Laboratory studies are useful only in excluding metabolic or toxic causes of seizures (eg, hyponatremia, hypoglycemia, drugs).
  • Prolactin and creatine kinase (CK) levels rise after generalized tonic-clonic seizures and not after other types of episodes. However, sensitivity is too low to be of any practical value (ie, lack of elevation does not exclude epileptic seizures).

Imaging Studies

  • Although imaging findings are normal in psychogenic nonepileptic seizures (PNES), images should be obtained to exclude organic pathology.
  • Incidental abnormalities are occasionally seen on imaging. However, they should not confound the diagnosis if results of EEG video monitoring firmly establish PNES.

Other Tests

  • EEG and ambulatory EEG
    • Because of its low sensitivity, routine EEG is not helpful in confirming a diagnosis of PNES. However, repeatedly normal EEG findings, especially in light of frequent attacks and resistance to medications, can be viewed as a red flag.
    • Ambulatory EEG is increasingly used, it is cost effective, and it can contribute to the diagnosis by recording the habitual episode and documenting the absence of EEG changes.
    • However, because of the difficulties in diagnosis (see Treatment), PNES should always be confirmed with EEG video monitoring.
  • EEG video monitoring
    • EEG video monitoring is the criterion standard for diagnosis and indicated in all patients who have frequent seizures despite taking medications. With an experienced epileptologist, combined electroclinical analysis of both the clinical semiology of the ictus and the ictal EEG findings allows for a definitive diagnosis in nearly all cases. If an episode is recorded, the diagnosis is usually easy, and PNES can usually be differentiated from epilepsy. The principle is to record an episode and demonstrate that no change in the EEG occurs during the clinical event and that the clinical episode is not consistent with seizures unaccompanied by EEG changes. Ictal EEG has limitations because of occasional false-negative results or uninterpretable results if movements generate excessive artifact.
    • Analysis of the ictal semiology (ie, video) is at least as important as ictal EEG because it often shows behaviors that are obviously and unquestionably nonorganic and incompatible with epileptic seizures. Certain characteristics of the motor phenomena are strongly associated with PNES: gradual onset or termination; pseudosleep; and discontinuous (stop-and-go), irregular, or asynchronous (out-of-phase) activity (eg, side-to-side head movement, pelvic thrusting, opisthotonic posturing, stuttering, weeping). A useful sign is preserved awareness during bilateral motor activity; this is relatively specific for PNES because unresponsiveness is almost always present during bilateral motor activity.
    • In experienced hands, EEG video monitoring is a highly reliable tool, and in the vast majority of cases, the diagnosis of PNES is not difficult. A small percentage of difficult cases account for the less-than-perfect interrater reliability.5
    • For more information, see the eMedicine article EEG Video Monitoring.
  • Short-term outpatient EEG video monitoring with activation
    • When the clinical findings strongly suggest PNES, patients can undergo short-term outpatient EEG video monitoring with activation, as an extension of induction.
    • This study can be cost-effective while retaining the same specificity as other tests and reasonably high sensitivity.
    • In 1 series, 10 of 15 patients had their habitual nonepileptic seizures with hyperventilation plus photic stimulation plus suggestion.
    • At the author's center, this test is routinely used, and the typical episode is observed in 70-80% of patients, obviating long-term EEG video monitoring.6
  • Inductions
    • Provocative techniques, activation procedures, or inductions, can be extremely useful for the diagnosis of PNES, particularly when the diagnosis is uncertain and no spontaneous episodes occur during monitoring.
    • Many epilepsy centers use a provocative technique to aid in the diagnosis of PNES.
    • An intravenous injection of saline is traditionally and most commonly used, but other techniques may be preferable.
    • The principle behind provocative techniques is suggestibility, which is a feature of somatoform disorders in general. For example, in psychogenic movement disorders, for which the diagnosis rests solely on phenomenology (ie, not equivalent to EEG), the response to placebo or suggestion is considered a diagnostic criterion for a definite psychogenic mechanism.

More on Psychogenic Nonepileptic Seizures

Overview: Psychogenic Nonepileptic Seizures
Differential Diagnoses & Workup: Psychogenic Nonepileptic Seizures
Treatment & Medication: Psychogenic Nonepileptic Seizures
Follow-up: Psychogenic Nonepileptic Seizures
Multimedia: Psychogenic Nonepileptic Seizures
References
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Further Reading

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Keywords

psychogenic seizures, PNES, non-epileptic seizures, psychogenic seizure, nonepileptic seizures, NES, pseudoseizures, nonepileptic episode, nonepileptic events, psychogenic nonepileptic events

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Contributor Information and Disclosures

Author

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association
Disclosure: UCB Pharma Honoraria Speaking, consulting; Lundbeck Honoraria Speaking, consulting; Cyberonics Honoraria Speaking, consulting; Glaxo Smith Kline Honoraria Speaking, consulting; Ortho McNeil Honoraria Speaking, consulting; Pfizer Honoraria Speaking, consulting; Sleepmed/DigiTrace  Speaking, consulting

Medical Editor

Raj D Sheth, MD, Professor, Mayo College of Medicine; Chief, Division of Pediatric Neurology, Nemours Children's Clinic
Raj D Sheth, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, American Epilepsy Society, American Neurological Association, and Child Neurology Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Jose E Cavazos, MD, PhD, FAAN, Associate Professor with Tenure, Departments of Neurology, Pharmacology, and Physiology, University of Texas Health Science Center at San Antonio; Co-Director, South Texas Comprehensive Epilepsy Center; Director of the Epilepsy Center, Audie L Murphy Veterans Affairs Medical Center
Jose E Cavazos, MD, PhD, FAAN is a member of the following medical societies: American Academy of Neurology, American Clinical Neurophysiology Society, American Epilepsy Society, American Neurological Association, and Society for Neuroscience
Disclosure: Nothing to disclose.

CME Editor

Paul E Barkhaus, MD, Professor, Department of Neurology, Medical College of Wisconsin; Director of Neuromuscular Diseases, Milwaukee Veterans Administration Medical Center
Paul E Barkhaus, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Neurological Association
Disclosure: Nothing to disclose.

Chief Editor

Helmi L Lutsep, MD, Professor, Department of Neurology, Oregon Health & Science University; Associate Director, Oregon Stroke Center
Helmi L Lutsep, MD is a member of the following medical societies: American Academy of Neurology and American Stroke Association
Disclosure: Co-Axia Consulting fee Review panel membership; AGA Medical Consulting fee Review panel membership; Boehringer Ingelheim Honoraria Speaking and teaching; Concentric Medical Consulting fee Review panel membership; Abbott Consulting fee Consulting; Sanofi Consulting fee Consulting

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