Altered Brain Microstate Dynamics in Adolescents with Narcolepsy.

Anne-Marie Landtblom,Henriettae Ståhlbrandt,Natasha M. Drissi,Anna Wretman,Martin Ulander,Niklas Darin,Maria Engström,Tove Hallböök,Attila Szakács,Suzanne T. Witt

doi:10.3389/fnhum.2016.00369

Anne-Marie Landtblom, Henriettae Ståhlbrandt + Show 8 more

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https://doi.org/10.3389/fnhum.2016.00369

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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.

Highlights

Narcolepsy is a chronic sleep disorder, characterized by excessive daytime sleepiness with frequent uncontrollable sleep attacks (Silber et al, 2002; Dauvilliers et al, 2007)
Narcolepsy diagnoses were based on the classification codes of the Swedish version of the International Classification of Diseases, Tenth Revision (ICD-10) and the diagnostic criteria for narcolepsy according to the 2005 International Classification of Sleep Disorders (American Academy of Sleep Medicine, 2005)
We did note that the narcolepsy patients had a higher overall body mass index (BMI) compared with the healthy controls (p < 0.039), where the narcolepsy patients had a mean BMI of 25.6 and the controls 21.7

Summary

Introduction

Narcolepsy is a chronic sleep disorder, characterized by excessive daytime sleepiness with frequent uncontrollable sleep attacks (Silber et al, 2002; Dauvilliers et al, 2007). EEG Microstate Dynamics in Narcolepsy and nocturnal dyssomnia with fragmented sleep and frequent awakenings. Most narcolepsy patients suffer from cataplexy, a sudden reduction or loss of muscular tone not accompanied by loss of consciousness caused by the loss of hypocretin-1 (orexin) producing neurons in the lateral hypothalamus (Lin et al, 1999; Thannickal et al, 2000; Nishino et al, 2010). In addition to the sleep-related changes summarized here, the loss of hypocretin-1 is thought to be an underlying cause to the changes in cognition observed in patients with narcolepsy (Fulda and Schulz, 2001; Rieger et al, 2003; Naumann et al, 2006; Bayard et al, 2012)

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