Our goal is to characterize EEG abnormalities in patients with psychogenic non epileptic seizures (PNES) with and without epilepsy as well as examine the relationship between EEG and imaging in this cohort at a Level-4 Epilepsy center. 

Prior studies have shown that PNES patients have higher rates of EEG abnormalities; both epileptiform and non-epileptiform as compared to the general population. Studies have noted EEG changes in patients with PNES. For most of these studies, studying EEG abnormalities were not a primary goal. These studies were older, had smaller sample sizes, some were in specific groups (children, neurological conditions, developmentally delayed people ) or did not distinguish between underlying cerebral disorders vs or epilepsy. In one recent larger study, which did find higher rate of interictal EEG abnormalities in patients with PNES (1.8 times more likely, this did not reach significance) but used routine EEGs to study interictal data.

Retrospective chart review of all patients discharged from the Epilepsy Monitoring Unit between 1/2016 and 12/2018.

287 patients with PNES and 17 with PNES and epilepsy (PNES+E) were included. Age was mean of 41years (PNES) and 39 years (PNES+E). 78.4% of PNES patients had normal interictal EEG, 21.6% had abnormal interictal EEG. 17.6% of PNES+E patients had normal interictal EEG and 82.4% had abnormal interictal EEG. Overall, 15.1 % of patients had an interictal epileptiform abnormality. 10.8% of pts with PNES had epileptiform discharges as compared to 88.2% of patients with PNES+E. Overall, 17.4% of the total pts had a non-epileptiform abnormality on their EEG.In the PNES group, this was 16% and in the PNES+E group, it was 41.2%

Patients with PNES have a much higher rate of epileptiform discharges at 11% compared to the general population (~2%)