Objective: The diagnosis of psychogenic nonepileptic seizures (PNES) can be challenging. In the absence of a gold standard to verify the reliability of the diagnosis by EEG-video, we sought to assess the interrater reliability of the diagnosis using EEG-video recordings.Methods: Patient samples consisted of 22 unselected consecutive patients who underwent EEGvideo monitoring and had at least an episode recorded. Other test results and histories were not provided because the goal was to assess the reliability of the EEG-video. Data were sent to 22 reviewers, who were board-certified neurologists and practicing epileptologists at epilepsy centers. Choices were 1) PNES, 2) epilepsy, and 3) nonepileptic but not psychogenic ("physiologic") events. Interrater agreement was measured using a coefficient for each diagnostic category. We used generalized coefficients, which measure the overall level of between-method agreement beyond that which can be ascribed to chance. We also report category-specific values.
Results:
Conclusions:Interrater reliability for the diagnosis of psychogenic nonepileptic seizures by EEGvideo monitoring was only moderate. Although this may be related to limitations of the study (diagnosis based on EEG-video alone, artificial nature of the forced choice paradigm, single episode), it highlights the difficulties and subjective components inherent to this diagnosis.