Epileptic vs. Psychogenic Nonepileptic Seizures: What Are the Distinguishing Signs?

Summary and Comment |
May 24, 2011

Epileptic vs. Psychogenic Nonepileptic Seizures: What Are the Distinguishing Signs?

  1. Robert C. Knowlton, MD, MSPH

Six signs were found to consistently distinguish epileptic from nonepileptic seizures, but eyewitnesses did not identify those signs accurately.

  1. Robert C. Knowlton, MD, MSPH

Among the most underappreciated costs and patient burdens in seizure disorders are those of misdiagnosis of epileptic seizures (ES) and delayed diagnosis of psychogenic nonepileptic seizures (PNES). To see whether clinical history could facilitate diagnosis, researchers sought to determine which seizure signs distinguish between ES and PNES and whether eyewitnesses accurately identify those signs.

Thirty-five adults were consecutively enrolled at an epilepsy monitoring unit. These patients, who experienced 120 video-documented seizures (36 PNES, 84 ES) seen by eyewitnesses, were referred for inpatient evaluation with video electroencephalography (VEEG). Epileptologists, blinded to diagnosis information and EEG tracings, assessed the video recordings of the seizures for the presence or absence of 48 prespecified semiological signs (roughly equally divided between PNES and ES signs).

Associations between epileptologists' identifications of signs and VEEG-determined diagnoses were assessed in the original 35-patient cohort and in a validation cohort of 36 patients. Statistically significant associations were found for six signs: three for PNES (“preserved awareness,”“eye flutter,” and “others [bystanders] can intensify or alleviate [the seizure]”) and three for ES (“eye opening or widening at onset,”“abrupt onset,” and “[postseizure] confusion/sleep”). However, eyewitnesses' reports of these six signs were not accurate and, therefore, not significantly associated with VEEG-determined diagnoses.

Comment

The findings of this well-designed prospective study confirm the difficult clinical challenge of diagnosing PNES accurately. Remarkably, it is not uncommon for patients with PNES to be diagnosed with and treated for epilepsy for years (although not nearly the “average” of 7 to 10 years that the authors assert). The authors call for better education of seizure patients' family members in how to identify the most diagnostically useful and reliable signs. That proposal is reasonable, but more obvious is the need to educate healthcare providers and insurers that prompt VEEG monitoring is indicated in all patients with uncontrolled seizures, regardless of what seizure type is suspected.

Citation(s):

Reader Comments (2)

Antonio Carlos Fonseca Silveira

Teach family members to differentiate ES of PNES would help us a lot in time to treat these patients. For us, the diagnosis is easily accomplished in the emergency services when the patient is convulsing.However, reports of seizures outside the hospital, witnessed by lay people are difficult to measure. I agree that all patients with uncontrolled seizures, regardless of what seizure type is suspected should be monitored with VEEGs.

Competing interests: professional relationships

SURESH RAMA CHANDRAN

In a PNES with convulsions the limb movements have an active flexion and extension, where as in ES only the flexion is active and the extension is passive.

Competing interests: None declared

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