Clinical predictors of psychogenic nonepileptic seizures - A critically appraised topic

Background: Psychogenic nonepileptic seizures (PNES) are often disabling and usually associated with psychiatric disorders and reduced quality of life. Although often suspected based on historical and clinical features, the gold standard for diagnosis of PNES is video electroencephalography. Identification of clinical features that reliably distinguish PNES from ES would be valuable in acute care settings, for patients that have coexisting disorders, and those with multiple event types. Objective: To determine the diagnostic value of putative clinical symptoms or signs of PNES against the gold standard of video electroencephalography. Methods: We addressed the objective through development of a structured critically appraised topic that included a clinical scenario, structured question, search strategy, critical appraisal, results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and content experts in the field of epileptology. Results: There were wide variations in the rates of coexisting PNES and epilepsy and study methodology. Ictal stuttering and the teddy bear sign were associated with moderate specificity for PNES. However, the presence of pelvic thrusting or ictal eye closure did not accurately distinguish PNES from ES. Conclusions: The presence of either ictal stuttering or the teddy bear sign is moderately specific but poorly sensitive for PNES. Pelvic thrusting and ictal eye closure are not reliable indicators of PNES. Future studies should establish more precise and reliable definitions of clinical signs and evaluate combinations of such signs in a broad spectrum of patients with PNES and ES spell phenotypes that may be difficult to distinguish, such as spells of unresponsiveness with motor manifestations. Because PNES and ES may coexist, analysis of diagnostic accuracy of clinical features should be performed for individual spells.