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

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

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Does rapid eye movement sleep behavior disorder exist in psychiatric populations? A clinical and polysomnographic case-control study

Objectives: Rapid eye movement (REM) sleep behavior disorder (RBD) has been increasingly reported in patients with psychiatric disorders (pRBD). Although a close association with the usage of psychotropics has been postulated, it remains elusive whether psychotropics are the only causative factor of RBD symptoms in psychiatric populations. Moreover, there is limited literature documenting and quantifying the clinical and polysomnographic features in this population. Methods: A case-control study comparing the clinical and polysomnographic features of 31 pRBD patients with: (1) Age-, sex-, and psychiatric diagnoses-matched controls; and (2) Typical idiopathic RBD (tRBD) patients. Results: Despite being prescribed with similar psychotropics, pRBD patients had more dream-enacting behaviors (p<. 0.01), sleep-related injuries (p<. 0.01), and nightmares (p<. 0.01) than the psychiatric controls. pRBD patients were younger with more females, but they had comparable sleep-related injuries to tRBD. Both tRBD and pRBD had more REM-related muscle activity than controls (p<. 0.01) and the effect remained significant after adjusting for age, gender, and use of antidepressants. Conclusions: Our study suggests that pRBD had comparable clinical features and consequences to those of tRBD. The occurrence of RBD symptoms in these patients may be related to a constellation of factors, including individual predisposition, depressive illness, antidepressants, and other clinical factors. Given the association of RBD and neurodegeneration in tRBD, further prospective follow-up of these patients is warranted. © 2012 Elsevier B.V.Link_to_subscribed_fulltex