Abnormal functional connectivity density in psychogenic non-epileptic seizures

Purpose: Psychogenic non-epileptic seizures (PNES) are paroxysmal behaviors that resemble epileptic seizures but lack abnormal electrical activity. Some neuroimaging studies have reported that PNES exhibits aberrant functional connectivity in specific brain networks. Thus, advanced neuroimaging technologies may aid clinical diagnosis and treatment of PNES. Methods: We investigated changes in brain functional connectivity in 18 patients with PNES and 20 healthy controls. Functional connectivity density mapping (FCDM), a voxelwise data-driven technique, was employed to compute local and global FCD maps. Then, short-range and long-range FCD values were calculated and group analyses performed between patents with PNES and healthy controls. A correlation analysis with clinical variables was also performed. Results: We found that patients with PNES showed abnormal FCD regions mainly in the frontal cortex, sensorimotor cortex, cingulate gyrus, insula and occipital cortex. Seed-voxel correlation analyses also showed disrupted functional connectivity between these regions. In addition, the occipital cortex FCD correlated with duration of disease. Conclusion: The present results support the hypothesis that patients with PNES are associated with altered attention, sensorimotor and emotion systems. Furthermore, correlations between altered regions in the occipital cortex and duration of disease may reflect an adaptation in these patients for long-term hypervigilance and increased response to external stimuli. This study adds new knowledge to our understanding of the pathophysiological mechanisms underlying PNES. (C) 2014 Elsevier B.V. All rights reserved.