Resting-state networks and dissociation in psychogenic non-epileptic seizures.
OBJECTIVE
Psychogenic non-epileptic seizures (PNES) are epilepsy-like episodes which have an emotional rather than organic origin. Although PNES have often been related to the process of dissociation, the psychopathology is still poorly understood. To elucidate underlying mechanisms, the current study applied independent component analysis (ICA) on resting-state fMRI to investigate alterations within four relevant networks, associated with executive, fronto-parietal, sensorimotor, and default mode activation, and within a visual network to examine specificity of between-group differences.


METHODS
Twenty-one patients with PNES without psychiatric or neurologic comorbidities and twenty-seven healthy controls underwent resting-state functional MR imaging at 3.0T (Philips Achieva). Additional neuropsychological testing included Raven's Matrices test and dissociation questionnaires. ICA with dual regression was used to identify resting-state networks in all participants, and spatial maps of the networks of interest were compared between patients and healthy controls.


RESULTS
Patients displayed higher dissociation scores, lower cognitive performance and increased contribution of the orbitofrontal, insular and subcallosal cortex in the fronto-parietal network; the cingulate and insular cortex in the executive control network; the cingulate gyrus, superior parietal lobe, pre- and postcentral gyri and supplemental motor cortex in the sensorimotor network; and the precuneus and (para-) cingulate gyri in the default-mode network. The connectivity strengths within these regions of interest significantly correlated with dissociation scores. No between-group differences were found within the visual network, which was examined to determine specificity of between-group differences.


CONCLUSIONS
PNES patients displayed abnormalities in several resting-state networks that provide neuronal correlates for an underlying dissociation mechanism.
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Departments of Neurology, Maastricht University Medical Centre, Maastricht, The Netherlands.
Sylvie J M
SJ
van der Kruijs
Department of Electrical Engineering, University of Technology, Eindhoven, The Netherlands.
Sridhar R
SR
Jagannathan
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
Nynke M G
NM
Bodde
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Departments of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
René M H
RM
Besseling
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
Richard H C
RH
Lazeron
Reference Centre for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium.
Kristl E J
KE
Vonck
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Reference Centre for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium.
Paul A J M
PA
Boon
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Department of Electrical Engineering, University of Technology, Eindhoven, The Netherlands.
Pierre J M
PJ
Cluitmans
Departments of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Paul A M
PA
Hofman
Departments of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Walter H
WH
Backes
Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Department of Electrical Engineering, University of Technology, Eindhoven, The Netherlands; Departments of Neurology, Maastricht University Medical Centre, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands; Reference Centre for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium.
Albert P
AP
Aldenkamp
Departments of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands; School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands. Electronic address: jacobus.jansen@mumc.nl.
Jacobus F A
JF
Jansen
D000328:Adult; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D001931:Brain Mapping; D004213:Dissociative Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011602:Psychophysiologic Disorders / Q000503:physiopathology*; D012146:Rest; D012640:Seizures / Q000150:complications / Q000473:pathology / Q000523:psychology; D013223:Statistics as Topic; D011795:Surveys and Questionnaires
D010100:Oxygen
Dissociation; Independent component analysis; Magnetic resonance imaging; Psychogenic non-epileptic seizures; Resting-state networks