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Drissi NM, Warntjes M, Wessén A, Szakacs A, Darin N, Hallböök T, Landtblom AM, Gauffin H, Engström M. Structural anomaly in the reticular formation in narcolepsy type 1, suggesting lower levels of neuromelanin. Neuroimage Clin 2019; 23:101875. [PMID: 31174102 PMCID: PMC6551567 DOI: 10.1016/j.nicl.2019.101875] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/04/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022]
Abstract
The 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 sleep-maintenance, specifically through orexin projections from the hypothalamus regulating sleep stability, as well as the results from the connectivity analysis, suggest that the observed deviant area could be the locus coeruleus or other neuromelanin containing nuclei in the proximity of the superior cerebellar peduncle. Hypothetically, the R2 differences described in this paper could be due to lower levels of neuromelanin in this area of narcolepsy patients.
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Affiliation(s)
- Natasha Morales Drissi
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden
| | - Marcel Warntjes
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden
| | | | - Attila Szakacs
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Tove Hallböök
- Department of Pediatrics, Queen Silvia Children's Hospital, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, 416 50 Gothenburg, Sweden
| | - Anne-Marie Landtblom
- Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden; Department of Clinical and Experimental Medicine (IKE), Linköping University, 581 83 Linköping, Sweden; Department of Neuroscience, Uppsala University, 752 36 Uppsala, Sweden
| | - Helena Gauffin
- Department of Clinical and Experimental Medicine (IKE), Linköping University, 581 83 Linköping, Sweden
| | - Maria Engström
- Department of Medical and Health Sciences (IMH), Linköping University, 581 83 Linköping, Sweden; Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden.
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Witt ST, Drissi NM, Tapper S, Wretman A, Szakács A, Hallböök T, Landtblom AM, Karlsson T, Lundberg P, Engström M. Evidence for cognitive resource imbalance in adolescents with narcolepsy. Brain Imaging Behav 2019; 12:411-424. [PMID: 28321606 PMCID: PMC5880867 DOI: 10.1007/s11682-017-9706-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
Abstract
The study investigated brain activity changes during performance of a verbal working memory task in a population of adolescents with narcolepsy. Seventeen narcolepsy patients and twenty healthy controls performed a verbal working memory task during simultaneous fMRI and EEG acquisition. All subjects also underwent MRS to measure GABA and Glutamate concentrations in the medial prefrontal cortex. Activation levels in the default mode network and left middle frontal gyrus were examined to investigate whether narcolepsy is characterized by an imbalance in cognitive resources. Significantly increased deactivation within the default mode network during task performance was observed for the narcolepsy patients for both the encoding and recognition phases of the task. No evidence for task performance deficits or reduced activation within the left middle frontal gyrus was noted for the narcolepsy patients. Correlation analyses between the spectroscopy and fMRI data indicated that deactivation of the anterior aspect of the default mode in narcolepsy patients correlated more with increased concentrations of Glutamate and decreased concentrations of GABA. In contrast, deactivation in the default mode was correlated with increased concentrations of GABA and decreased concentrations of Glutamate in controls. The results suggested that narcolepsy is not characterized by a deficit in working memory but rather an imbalance of cognitive resources in favor of monitoring and maintaining attention over actual task performance. This points towards dysregulation within the sustained attention system being the origin behind self-reported cognitive difficulties in narcolepsy.
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Affiliation(s)
- Suzanne T Witt
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.
| | - Natasha Morales Drissi
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
| | - Sofie Tapper
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Radiation Physics, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Anna Wretman
- Linnaeus Center HEAD, Linköping University, Linköping, Sweden
| | - Attila Szakács
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Tove Hallböök
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anne-Marie Landtblom
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Department of Neurology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.,Department of Neuroscience and Neurology, Uppsala University, Uppsala, Sweden
| | - Thomas Karlsson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Linnaeus Center HEAD, Linköping University, Linköping, Sweden.,Department of Behavioral Sciences and Learning, Linköping University, Linköping, Sweden
| | - Peter Lundberg
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Radiation Physics, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Radiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Maria Engström
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköpings universitet/US, SE-581 85, Linköping, SE, Sweden.,Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
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Morales Drissi N, Romu T, Landtblom AM, Szakács A, Hallböök T, Darin N, Borga M, Leinhard OD, Engström M. Unexpected Fat Distribution in Adolescents With Narcolepsy. Front Endocrinol (Lausanne) 2018; 9:728. [PMID: 30574118 PMCID: PMC6292486 DOI: 10.3389/fendo.2018.00728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 11/16/2018] [Indexed: 02/02/2023] Open
Abstract
Narcolepsy type 1 is a chronic sleep disorder with significantly higher BMI reported in more than 50% of adolescent patients, putting them at a higher risk for metabolic syndrome in adulthood. Although well-documented, the body fat distribution and mechanisms behind weight gain in narcolepsy are still not fully understood but may be related to the loss of orexin associated with the disease. Orexin has been linked to the regulation of brown adipose tissue (BAT), a metabolically active fat involved in energy homeostasis. Previous studies have used BMI and waist circumference to characterize adipose tissue increases in narcolepsy but none have investigated its specific distribution. Here, we examine adipose tissue distribution in 19 adolescent patients with narcolepsy type 1 and compare them to 17 of their healthy peers using full body magnetic resonance imaging (MRI). In line with previous findings we saw that the narcolepsy patients had more overall fat than the healthy controls, but contrary to our expectations there were no group differences in supraclavicular BAT, suggesting that orexin may have no effect at all on BAT, at least under thermoneutral conditions. Also, in line with previous reports, we observed that patients had more total abdominal adipose tissue (TAAT), however, we found that they had a lower ratio between visceral adipose tissue (VAT) and TAAT indicating a relative increase of subcutaneous abdominal adipose tissue (ASAT). This relationship between VAT and ASAT has been associated with a lower risk for metabolic disease. We conclude that while weight gain in adolescents with narcolepsy matches that of central obesity, the lower VAT ratio may suggest a lower risk of developing metabolic disease.
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Affiliation(s)
- Natasha Morales Drissi
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
| | - Thobias Romu
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
| | - Anne-Marie Landtblom
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine (IKE), Linköping University, Linköping, Sweden
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Attilla Szakács
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Tove Hallböök
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Darin
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Borga
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
- Department of Biomedical Engineering (IMT), Linköping University, Linköping, Sweden
| | - Olof Dahlqvist Leinhard
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- AMRA Medical AB, Linköping, Sweden
| | - Maria Engström
- Department of Medical and Health Sciences (IMH), Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
- *Correspondence: Maria Engström
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