Association of interictal EEG findings in those with concomitant epileptic seizures and PNES
Gabriela Alejo1, Olivia Iheme2, Brendan Kelley2
1Jackson Memorial Hospital, 2University of Texas Southwestern
Objective:
To assess whether epileptics with EEG abnormalities in the right hemisphere have a higher rate of concomitant PNES.
Background:
PNES is classified as a functional neurological disorder (FND), however, more recently, various studies have attempted to elucidate structural, anatomical, or molecular alterations that might implicate certain regions of the brain in the development of functional disorders, like PNES.
Design/Methods:
We performed a retrospective chart review of patients ages 18-69 who were admitted to the Epilepsy Monitoring Unit at Parkland Hospital between the years 2016-2018. Information was abstracted from EEG reports of patients diagnosed with epileptic seizures (ES) and concomitant Psychogenic Non-epileptic seizures (PNES) and ES. The relationship between R-sided EEG abnormalities and a concomitant diagnosis of PNES was explored using odds ratios.
Results:
There were 140 patients with ES alone, and 47 patients with PNES+ES. The odds ratios for R-sided ictal, epileptiform interictal, and non-epileptiform interictal abnormalities on EEG were 1.044 [95% confidence interval(CI) (0.26, 4.15)], 2.652 [95% CI (0.97, 7.24)], and 4.769 [95% CI of (1.71, 13.27)], respectively.
Conclusions:
In patients with concomitant ES+PNES, there is a greater likelihood of finding R-sided ictal and interictal findings on EEG. Our findings support an association between R-sided interictal abnormalities and concomitant PNES in people having epilepsy, consistent with previous research suggesting R-sided neuroanatomical structures having a role in the development of PNES. Specifically, abnormal cortical function in neuroanatomical regions involved in emotion and delusion may be hypothesized to a mediate a relationship between PNES and the right hemisphere of the brain.