Functional seizures: clinical features

General features

• They may arise from apparent sleep but EEG verifies wakefulness
• They may however also arise from slow wave sleep
• The onset is gradual with a waxing and waning course
• There is no tonic phase
• About 60% have stereotyped events
• They are prolonged events usually lasting more than 2 minutes
• Injury avoidance is characteristic
• There may be experiential avoidance
• There is memory recall

References

1. LaFrance WC Jr, Baker GA, Duncan R, Goldstein LH, Reuber M. Minimum requirements for the diagnosis of psychogenic nonepileptic seizures: a staged approach: a report from the International League Against Epilepsy Nonepileptic Seizures Task Force. Epilepsia 2013; 54:2005-2018. 
2. Mellers JDC. The approach to patients with "non-epileptic seizures". Postgrad Med J 2005; 81:498-504.
3. Avbersek A, Sisodiya S. Does the primary literature provide support for clinical signs used to distinguish psychogenic nonepileptic seizures from epileptic seizures? JNNP 2010; 81:719-725.
4. Duncan R. How do you identify and manage convulsive psychogenic nonepileptic seizures presenting acutely to casualty? ACNR 2012; 12:18-20.
5. Higgins S, Koutroumanidis M. Psychogenic non-epileptic seizures arising almost exclusively from sleep. Seizure 2022; 99:43-47.
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Related checklists

• Functional seizures: risk factors
• Functional seizures: clinical patterns
• Functional seizures: course and complications
• Functional seizures: differentials
• Functional seizures: outcomes