Literature Review

Task Force Identifies Requirements for Diagnosing Psychogenic Seizures



In areas where video EEG (vEEG) is not available, clinicians can use a staged approach to diagnosing psychogenic nonepileptic seizures (PNES) that incorporates medical histories, eyewitness accounts, and video recordings of seizure activity, according to a task force of the International League Against Epilepsy. Their report was published in the November issue of Epilepsia.

Most patients with recurrent seizures are presumed to have epilepsy and are treated with antiepileptic drugs (AEDs), but AEDs could exacerbate PNES. Therefore, early and accurate recognition of PNES is “of paramount importance,” said W. Curt LaFrance, Jr., MD, Assistant Professor of Psychiatry and Neurology at Brown University in Providence, Rhode Island, and leader of the task force. Diagnosis is complicated by the fact that epilepsy is a recognized risk factor for the development of PNES.

The task force’s report aims “to provide greater clarity about the process and certainty of the diagnosis of PNES, with the intent to improve the care for people with epilepsy and nonepileptic seizures,” said the investigators. “The ability to diagnose PNES when vEEG is not available may open opportunities to lower and middle income countries where monitoring is not available.”

The authors reviewed the medical literature to evaluate approaches to diagnosing PNES, including taking a history; EEG; ambulatory EEG; vEEG or monitoring; neurophysiologic, neurohumoral, neuroimaging, and neuropsychologic testing; hypnosis; and conversation analysis.

The combination of vEEG with history taken from patients and witnesses is the diagnostic standard, “however, vEEG is not available in some locations, and in some patients, events cannot be recorded,” said the task force.

The group proposed the following four categories of certainty for PNES diagnosis and their respective requirements:

• Documented PNES relies on clinical history plus a vEEG recording of habitual events.

• Clinically established PNES is defined by a clinical history, clinician witness, and ambulatory EEG recording of habitual event or events without video. This diagnosis would be appropriate if a clinician witness observed a seizure and documented the exam findings typically found in PNES, such as resisted eye-opening, or if a clinician could review a non-EEG event by video or in person.

• Probable PNES is determined by a clinical history, a clinician review of video recording or live events, and a normal interictal EEG. This diagnosis would be appropriate if a clinician could review a home or cell phone video recording of seizure activity or witness it in person.

• Possible PNES relies on clinical history from the patient or witness and a normal interictal EEG. At minimum, a patient’s history and description of events and an eyewitness description could help identify possible PNES, but without the clinician “observing the ictus on video or in person, an alternative diagnosis of epilepsy would have to be considered very carefully,” said the investigators.

—Karen Blum
IMNG Medical News

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