Structural anomaly in the reticular formation in narcolepsy type 1, suggesting lower levels of neuromelanin

Publication date: Available online 29 May 2019Source: NeuroImage: ClinicalAuthor(s): Natasha Morales Drissi, Marcel Warntjes, Alexander Wessén, Attila Szakacs, Niklas Darin, Tove Hallböök, Anne-Marie Landtblom, Helena Gauffin, Maria EngströmAbstractThe aim of this study was to investigate structural changes in the brain stem of adolescents with narcolepsy, a disorder characterized by excessive daytime sleepiness, fragmented night-time sleep, and cataplexy. For this purpose, we used quantitative magnetic resonance imaging to obtain R1 and R2 relaxation rates, proton density, and myelin maps in adolescents with narcolepsy (n = 14) and healthy controls (n = 14). We also acquired resting state functional magnetic resonance imaging (fMRI) for brainstem connectivity analysis. We found a significantly lower R2 in the rostral reticular formation near the superior cerebellar peduncle in narcolepsy patients, family wise error corrected p = .010. Narcolepsy patients had a mean R2 value of 1.17 s−1 whereas healthy controls had a mean R2 of 1.31 s−1, which was a large effect size with Cohen d = 4.14. We did not observe any significant differences in R1 relaxation, proton density, or myelin content. The sensitivity of R2 to metal ions in tissue and the transition metal ion chelating property of neuromelanin indicate that the R2 deviant area is one of the neuromelanin containing nuclei of the brain stem. The close proximity and its demonstrated involvement in sle...
Source: NeuroImage: Clinical - Category: Radiology Source Type: research