Cognitive impairment is not equal in patients with epileptic and psychogenic nonepileptic seizures.
OBJECTIVE
Patients with psychogenic nonepileptic seizures (PNES) and those with epileptic seizures (ES) purportedly have roughly equal neurocognitive deficits. However, recent findings suggest that patients with somatoform disorders exhibit more variable effort on neurocognitive testing than do controls. We reexamined neurocognitive function in patients with ESs and PNES by using symptom validity testing to control for variability in effort.


METHODS
Patients referred for video-EEG monitoring were administered the Word Memory Test (WMT), a measure of symptom validity, as part of neuropsychological evaluation. Patients classified with ictal video-EEG recordings as having ES (n = 41) or PNES (n = 43) were compared on neurocognitive and WMT performance and demographic, psychiatric, and medical variables.


RESULTS
Striking rates of WMT failure were observed in the PNES (51.2%) group, but not in the ES (8.1%) group (p = <0.001) after controlling for false-positive errors. Although the PNES and ES groups reported equivalent neurologic histories, the PNES group exhibited less objective evidence of impairment as measured by valid neuropsychological testing, MRI of the brain, and video-EEG monitoring.


CONCLUSIONS
Many patients with PNES do not put forth maximal effort during neuropsychological assessment. When patients with PNES put forth valid effort, they demonstrate less objective evidence of neuropathologic injury or disease than do patients with ES. The cognitive impairment reported by this group appears to be more a function of motivational (although not necessarily intentional) factors than of verifiable neuropathology.
Drane
Daniel L
DL
Department of Neurology, University of Washington School of Medicine, Seattle, WA 98104, USA. ddrane@u.washington.edu
Williamson
David J
DJ
Stroup
Elizabeth S
ES
Holmes
Mark D
MD
Jung
Matthew
M
Koerner
Erich
E
Chaytor
Naomi
N
Wilensky
Alan J
AJ
Miller
John W
JW
D000328:Adult; D001921:Brain / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D014743:Videotape Recording