Larger hypothalamic volume in narcolepsy type 1

• Published in: Sleep (New York, N.Y.) Vol. 46; no. 11; p. 1
• Main Authors: Juvodden, Hilde T, Alnæs, Dag, Lund, Martina J, Agartz, Ingrid, Andreassen, OIe A, Server, Andres, Thorsby, Per M, Westlye, Lars T, Knudsen Heier, Stine
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 08-11-2023
• Subjects: Adolescent; Adult; Analysis; Brain; Child; Female; Gliosis; Humans; Hypothalamus; Hypothalamus - diagnostic imaging; Influenza A Virus, H1N1 Subtype; Medical research; Medicine, Experimental; Narcolepsy; Neurological Disorders; Neurons; Orexins; Sleep; Sleep disorders; Type 2 diabetes; Young Adult; Norway; narcolepsy; MRI; T1; hypothalamus
• ISSN: 0161-8105; 1550-9109
• DOI: 10.1093/sleep/zsad173

Abstract
Study Objectives
Narcolepsy type 1 (NT1) is a neurological sleep disorder. Postmortem studies have shown 75%–90% loss of the 50 000–70 000 hypocretin-producing neurons and 64%–94% increase in the 64 000–120 000 histaminergic neurons and conflicting indications of gliosis in the hypothalamus of NT1 patients. The aim of this study was to compare MRI-based volumes of the hypothalamus in patients with NT1 and controls in vivo.
Methods
We used a segmentation tool based on deep learning included in Freesurfer and computed the volume of the whole hypothalamus, left/right part of the hypothalamus, and 10 hypothalamic subregions. We included 54 patients with post-H1N1 NT1 (39 females, mean age 21.8 ± 11.0 years) and 114 controls (77 females, mean age 23.2 ± 9.0 years). Group differences were tested with general linear models using permutation testing in Permutation Analysis of Linear Models and evaluated after 10 000 permutations, yielding two-tailed P-values. Furthermore, a stepwise Bonferroni correction was performed after dividing hypothalamus into smaller regions.
Results
The analysis revealed larger volume for patients compared to controls for the whole hypothalamus (Cohen’s d = 0.71, p = 0.0028) and for the left (d = 0.70, p = 0.0037) and right part of the hypothalamus (d = 0.65, p = 0.0075) and left (d = 0.72, p = 0.0036) and right tubular-inferior (d = 0.71, p = 0.0037) hypothalamic subregions.
Conclusions
In conclusion, patients with post-H1N1 NT1 showed significantly larger hypothalamic volume than controls, in particular in the tubular-inferior subregions which could reflect several processes as previous studies have indicated neuroinflammation, gliosis, and changes in the numbers of different cell types.
Graphical Abstract