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Although psychogenic nonepileptic seizures (PNES) are considered a stress-induced paroxysmal disintegration of cognitive functions, it remains unknown whether stress indeed impairs cognitive integrative functions, such as working memory (WM), in patients with PNES. An N-back task with emotional distracters (angry, happy, and neutral faces) was administered at baseline and after stress induction (Cold Pressor Test) to 19 patients with PNES and 20 matched healthy controls. At baseline, patients displayed increased WM interference for the facial distracters. After stress induction, group differences generalized to the no-distracter condition. Within patients, high cortisol stress responses were associated with larger stress-induced WM impairments in the no-distracter condition. These findings demonstrate that patients' cognitive integrative functions are impaired by social distracters and stress induction. Moreover, the stress- and cortisol-related generalization of the relative WM impairments offers a promising experimental model for the characteristic paroxysmal disintegration of attentional and mnemonic functions in patients with PNES associated with stress., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Previous studies have provided evidence for a vigilant attentional bias toward threat stimuli and increased basal diurnal cortisol levels in patients with psychogenic nonepileptic seizures (PNES). Because cortisol levels may be predictive of threat vigilance, we reanalyzed previous data on threat vigilance in 19 unmedicated patients with PNES and found a positive correlation between baseline cortisol levels and attentional bias scores for threat stimuli (r=0.49, P=0.035). There was no such relationship in healthy matched controls (n=20) or in patients with epileptic seizures (n=17). These findings provide the first evidence linking an endocrine stress marker to increased threat sensitivity in PNES and support new integrated psychoneurobiological models of PNES.