title: Altered Brain Microstate Dynamics in Adolescents with Narcolepsy.
abstract: Narcolepsy is a chronic sleep disorder caused by a loss of hypocretin-1 producing neurons in the hypothalamus. Previous neuroimaging studies have investigated brain function in narcolepsy during rest using positron emission tomography (PET) and single photon emission computed tomography (SPECT). In addition to hypothalamic and thalamic dysfunction they showed aberrant prefrontal perfusion and glucose metabolism in narcolepsy. Given these findings in brain structure and metabolism in narcolepsy, we anticipated that changes in functional magnetic resonance imaging (fMRI) resting state network (RSN) dynamics might also be apparent in patients with narcolepsy. The objective of this study was to investigate and describe brain microstate activity in adolescents with narcolepsy and correlate these to RSNs using simultaneous fMRI and electroencephalography (EEG). Sixteen adolescents (ages 13-20) with a confirmed diagnosis of narcolepsy were recruited and compared to age-matched healthy controls. Simultaneous EEG and fMRI data were collected during 10 min of wakeful rest. EEG data were analyzed for microstates, which are discrete epochs of stable global brain states obtained from topographical EEG analysis. Functional MRI data were analyzed for RSNs. Data showed that narcolepsy patients were less likely than controls to spend time in a microstate which we found to be related to the default mode network and may suggest a disruption of this network that is disease specific. We concluded that adolescents with narcolepsy have altered resting state brain dynamics.
authors.affiliation: Department of Medical and Health Sciences (IMH), Linköping UniversityLinköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping UniversityLinköping, Sweden.
authors.forename: Natasha M
authors.initials: NM
authors.lastname: Drissi
authors.affiliation: Department of Paediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg, Sweden.
authors.forename: Attila
authors.initials: A
authors.lastname: Szakács
authors.affiliation: Center for Medical Image Science and Visualization (CMIV), Linköping University Linköping, Sweden.
authors.forename: Suzanne T
authors.initials: ST
authors.lastname: Witt
authors.affiliation: Department of Behavioral Science and Learning, Linköping University Linköping, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Wretman
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping University Linköping, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Ulander
authors.affiliation: Department of Radiology, Medical Diagnostics, Highland Hospital Eksjö, Sweden.
authors.forename: Henriettae
authors.initials: H
authors.lastname: Ståhlbrandt
authors.affiliation: Department of Paediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg, Sweden.
authors.forename: Niklas
authors.initials: N
authors.lastname: Darin
authors.affiliation: Department of Paediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Gothenburg, Sweden.
authors.forename: Tove
authors.initials: T
authors.lastname: Hallböök
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping UniversityLinköping, Sweden; Department of Neurology, Uppsala UniversityUppsala, Sweden.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Landtblom
authors.affiliation: Department of Medical and Health Sciences (IMH), Linköping UniversityLinköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping UniversityLinköping, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Engström
keywords: default mode network; electroencephalography (EEG); functional magnetic resonance imaging (fMRI); microstates; narcolepsy; orexin; resting state networks; sleep