Interrater reliability of EEG-video monitoring.
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 EEG-video 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 kappa coefficient for each diagnostic category. We used generalized kappa coefficients, which measure the overall level of between-method agreement beyond that which can be ascribed to chance. We also report category-specific kappa values.


RESULTS
For the diagnosis of PNES, there was moderate agreement (kappa = 0.57, 95% confidence interval [CI] 0.39-0.76). For the diagnosis of epilepsy, there was substantial agreement (kappa = 0.69, 95% CI 0.51-0.86). For physiologic nonepileptic episodes, the agreement was low (kappa = 0.09, 95% CI 0.02-0.27). The overall kappa statistic across all 3 diagnostic categories was moderate at 0.56 (95% CI 0.41-0.73).


CONCLUSIONS
Interrater reliability for the diagnosis of psychogenic nonepileptic seizures by EEG-video 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.
Benbadis
S R
SR
University of South Florida and Tampa General Hospital, Tampa, FL, USA. sbenbadi@health.usf.edu
LaFrance
W C
WC
Papandonatos
G D
GD
Korabathina
K
K
Lin
K
K
Kraemer
H C
HC
D004569:Electroencephalography / Q000379:methods*; D006801:Humans; D012640:Seizures / Q000175:diagnosis* / Q000209:etiology; D014741:Video Recording