Our data show that lucid dreaming constitutes a hybrid state of consciousness with definable and measurable differences from waking and from REM sleep, particularly in frontal areas.

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Background: Sleep disturbances are common features in spinocerebellar ataxias (SCAs). Nevertheless, sleep data on SCA2 come from scarce studies including few patients, limiting the evaluation of the prevalence and determinants of sleep disorders. Objective: To assess the frequency and possible determinants of sleep disorders in the large and homogeneous SCA2 Cuban population. Methods: Thirty-two SCA2 patients and their age- and sex-matched controls were studied by video-polysomnography and sleep interviews. Results: The most striking video-polysomnography features were rapid eye movement (REM) sleep pathology and periodic leg movements (PLMs). REM sleep abnormalities included a consistent reduction of the REM sleep percentage and REM density as well as an increase in REM sleep without atonia (RWA). REM sleep and REM density decreases were closely related to the increase in ataxia scores, whereas the RWA percentage was influenced by the cytosine-adenine-guanine (CAG) repeats. PLMs were observed in 37.5% of cases. The PLM index showed a significant association with the ataxia score and disease duration but not with CAG repeats. Conclusions: REM sleep pathology and PLMs are closely related to SCA2 severity, suggesting their usefulness as disease progression markers. The RWA percentage is influenced by the CAG repeats and might thus be a sensitive parameter for reflecting polyglutamine toxicity. Finally, as PLMs are sensible to drug treatment, they represents a new therapeutic target for the symptomatic treatment of SCA2.

BackgroundDepersonalization-derealization syndrome (DDS) is an underdiagnosed and underresearched clinical phenomenon. In Germany, its administrative prevalence is far below the threshold for orphan diseases, although according to epidemiological surveys the diagnosis should be comparable frequent as anorexia nervosa for instance. Against this background, we carried out a large comprehensive survey of a DDS series in a tertiary mental health center with a specialized depersonalization-derealization clinic. To reveal differential characteristics, we compared the DDS patients, who consulted the specialized depersonalization-derealization clinic, with a group of patients with depressive disorders without comorbid DDS from the regular outpatient clinic of the mental health center.MethodsThe sample comprised 223 patients with a diagnosis of depersonalization-derealization-syndrome and 1129 patients with a depressive disorder but without a comorbid diagnosis of DDS. DDS patients were described and compared with depressive outpatients in terms of sociodemographic characteristics, treatment history, treatment wishes, clinical symptomatology, prevailing psychosocial stressors, family history of common mental disorders and history of childhood trauma.ResultsDespite the high comorbidity of DDS patients with depressive disorders and comparable burden with symptoms of depression and anxiety, the clinical picture and course of both patient groups differed strongly. DDS patients were younger, had a significant preponderance of male sex, longer disease duration and an earlier age of onset, a higher education but were more often unemployed. They tended to show more severe functional impairment. They had higher rates of previous or current mental health care utilization. Nearly all DDS patients endorsed the wish for a symptom specific counseling and 70.7 % were interested in the internet-based treatment of their problems. DDS patients had lower levels of self-rated traumatic childhood experiences and current psychosocial stressors. However, they reported a family history of anxiety disorders more often.ConclusionIn consideration of the selection bias of this study, this case series supports the view that the course of the DDS tends to be long-lasting. DDS patients are severely impaired, utilizing mental health care to a high degree, which nevertheless might not meet their treatment needs, as patients strongly opt for obtaining disorder specific counseling. In view of the size of the problem, more research on the disorder, its course and its optimal treatment is urgently required.Electronic supplementary materialThe online version of this article (doi:10.1186/s12888-016-0908-4) contains supplementary material, which is available to authorized users.

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