Affiliation:
1. Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
2. Emory Sleep Center, Emory Healthcare, Atlanta, GA, USA
3. Alanta Veterans Affairs Center for Visual and Neurocognitive Rehabilitation, Atlanta, GA, USA
4. Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
Abstract
Abstract
Study Objectives
Daytime sleepiness is a manifestation of multiple sleep and neurologic disorders. Few studies have assessed patterns of regional brain metabolism across different disorders of excessive daytime sleepiness. One such disorder, idiopathic hypersomnia (IH), is particularly understudied.
Methods
People with IH, narcolepsy (NT1), and non-sleepy controls underwent [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) with electroencephalography (EEG). Participants were instructed to resist sleep and were awoken if sleep occurred. Voxel-wise parametric analysis identified clusters that significantly differed between each pair of groups, with a minimum cluster size of 100 voxels at a cluster detection threshold of p < 0.005. Correlations between glucose metabolism and sleep characteristics were evaluated.
Results
Participants (77% women) had IH (n = 16), NT1 (n = 14), or were non-sleepy controls (n = 9), whose average age was 33.8 (±10.7) years. Compared to controls, NT1 participants demonstrated hypermetabolism in fusiform gyrus, middle occipital gyrus, superior and middle temporal gyri, insula, cuneus, precuneus, pre- and post-central gyri, and culmen. Compared to controls, IH participants also demonstrated hypermetabolism in precuneus, inferior parietal lobule, superior and middle temporal gyri, and culmen. Additionally, IH participants demonstrated altered metabolism of the posterior cingulate. Most participants fell asleep. Minutes of N1 during uptake was significantly negatively correlated with metabolism of the middle temporal gyrus.
Conclusion
NT1 and IH demonstrate somewhat overlapping, but distinct, patterns of regional metabolism.
Funder
National Institutes of Health
Department of Veterans Affairs
Publisher
Oxford University Press (OUP)
Subject
Physiology (medical),Clinical Neurology