Altered Sleep Stage Transitions of REM Sleep: A Novel and Stable Biomarker of Narcolepsy

Objectives: To determine the diagnostic values, longitudinal stability, and HLA association of the sleep stage transitions in narcolepsy. Methods: To compare the baseline differences in the sleep stage transition to REM sleep among 35 patients with type 1 narcolepsy, 39 patients with type 2 narcolepsy, 26 unaffected relatives, and 159 non-narcoleptic sleep patient controls, followed by a reassessment at a mean duration of 37.4 months. Results: The highest prevalence of altered transition from stage non-N2/N3 to stage R in multiple sleep latency test (MSLT) and nocturnal polysomnography (NPSG) was found in patients with type 1 narcolepsy (92.0% and 57.1%), followed by patients with type 2 narcolepsy (69.4% and 12.8%), unaffected relatives (46.2% and 0%), and controls (39.3% and 1.3%). Individual sleep variables had varied sensitivity and specifi city in diagnosing narcolepsy. By incorporating a combination of sleep variables, the decision tree analysis improved the sensitivity to 94.3% and 82.1% and enhanced specifi city to 82.4% and 83% for the diagnosis of type 1 and type 2 narcolepsy, respectively. There was a signifi cant association of DBQ1∗0602 with the altered sleep stage transition (OR = 16.0, 95% CI: 1.7-149.8, p = 0.015). The persistence of the altered sleep stage transition in both MSLT and NPSG was high for both type 1 (90.5% and 64.7%) and type 2 narcolepsy (92.3% and 100%), respectively. Conclusions: Altered sleep stage transition is a signifi cant and stable marker of narcolepsy, which suggests a vulnerable wake-sleep dysregulation trait in narcolepsy. Altered sleep stage transition has a signifi cant diagnostic value in the differential diagnosis of hypersomnias, especially when combined with other diagnostic sleep variables in decision tree analysis.Link_to_subscribed_fulltex

Prospective outcome of rapid eye movement sleep behaviour disorder: Psychiatric disorders as a potential early marker of Parkinson's disease

Link_to_subscribed_fulltex

Reduced striatal dopamine transmission in REM sleep behavior disorder comorbid with depression

© 2015 American Academy of Neurology. Objective: To investigate dopamine transmission in patients with comorbid REM sleep behavior disorder (RBD) and major depressive disorder (MDD). Methods: This is a case-control study including 11 medicated patients with comorbid RBD and MDD (mean age 47.5 6 8.2), 8 medicated patients with MDD only (mean age 47.9 6 8.4), and 10 healthy participants (mean age 46.5 6 10.6 years). They underwent clinical assessment, video-polysomnography, olfactory tests, and neuroimaging studies (18F-DOPA, 11C-raclopride, and 18F-FDG PET neuroimaging). Results: Compared with the 2 control groups, patients with comorbid RBD and MDD had significantly lower 18F-DOPA uptake at 60 minutes in the putamen and caudate after controlling for age and sex effect (p 18F-FDG-PET. The 18F-DOPA uptake in putamens had significant inverse correlation with severity of RBD symptoms (p <0.01) and REM-related tonic muscle activity (p <0.01). The comorbid RBD and MDD group had more impairment in olfactory function. Conclusion: Patients with comorbid RBD and MDD had presynaptic dopamine dysfunction and impaired olfactory function. There is a distinct possibility that the development of RBD symptoms among patients with MDD may represent an early phase of a-synucleinopathy neurodegeneration instead of a merely antidepressant-induced condition.Link_to_subscribed_fulltex