Background Idiopathic REM sleep behavior disorder (RBD) is a parasomnia that is an important risk factor for PD and Lewy body dementia. Its prevalence is unknown. One barrier to determining prevalence is that current screening tools are too long for large-scale epidemiologic surveys. Therefore, we designed the REM Sleep Behavior Disorder Single-Question Screen (RBD1Q), a screening question for dream enactment with a simple yes/no response. Methods Four hundred and eighty-four sleep-clinic– based participants (242 idiopathic RBD patients and 242 controls) completed the screen during a multicenter case-control study. All participants underwent a polysomnogram to define gold-standard diagnosis according to standard criteria. Results We found a sensitivity of 93.8% and a specificity of 87.2%. Sensitivity and specificity were similar in healthy volunteers, compared to controls or patients, with other sleep diagnoses. Conclusions A single-question screen for RBD may reliably detect disease, with psychometric properties favorably comparable to those reported for longer questionnaires.

In Parkinson’s disease, rapid eye movement sleep behaviour disorder is an early non-dopaminergic syndrome with nocturnal violence and increased muscle tone during rapid eye movement sleep that can precede Parkinsonism by several years. The neuronal origin of rapid eye movement sleep behaviour disorder in Parkinson’s disease is not precisely known; however, the locus subcoeruleus in the brainstem has been implicated as this structure blocks muscle tone during normal rapid eye movement sleep in animal models and can be damaged in Parkinson’s disease. Here, we studied the integrity of the locus coeruleus/subcoeruleus complex in patients with Parkinson’s disease using combined neuromelanin-sensitive, structural and diffusion magnetic resonance imaging approaches. We compared 24 patients with Parkinson’s disease and rapid eye movement sleep behaviour disorder, 12 patients without rapid eye movement sleep behaviour disorder and 19 age- and gender-matched healthy volunteers. All subjects underwent clinical examination and characterization of rapid eye movement sleep using video-polysomnography and multimodal imaging at 3 T. Using neuromelanin-sensitive imaging, reduced signal intensity was evident in the locus coeruleus/subcoeruleus area in patients with Parkinson’s disease that was more marked in patients with than those without rapid eye movement sleep behaviour disorder. Reduced signal intensity correlated with the percentage of abnormally increased muscle tone during rapid eye movement sleep. The results confirmed that this complex is affected in Parkinson’s disease and showed a gradual relationship between damage to this structure, presumably the locus subcoeruleus, and abnormal muscle tone during rapid eye movement sleep, which is the cardinal marker of rapid eye movement sleep behaviour disorder. In longitudinal studies, the technique may also provide early markers of non-dopaminergic Parkinson’s disease pathology to predict the occurrence of Parkinson’s disease.

Objective To assess whether risk factors for Parkinson’s disease and Dementia with Lewy bodies increase rate of defined neurodegenerative disease in idiopathic REM sleep behavior disorder Methods 12 centers administered a detailed questionnaire assessing risk factors for neurodegenerative synucleinopathy to patients with idiopathic REM sleep behavior disorder. Variables included demographics, lifestyle factors, pesticide exposures, occupation, co-morbid conditions, medication use, family history, and autonomic/motor symptoms. After 4-years follow-up, patients were assessed for dementia or parkinsonism. Disease risk was assessed with Kaplan-Meier analysis, and epidemiologic variables were compared between convertors and those still idiopathic using logistic regression. Results Of 305 patients, follow-up information was available for 279, of whom 93 (33.3%) developed defined neurodegenerative disease. Disease risk was 25% at 3 years, and 41% after 5 years. Patients who converted were older (difference=4.5 years, p<0.001), with similar sex distribution. Neither caffeine, smoking, nor alcohol exposure predicted conversion. Although occupation was similar between groups, those who converted had a lower likelihood of pesticide exposure (occupational insecticide=2.3% vs. 9.0%). Convertors were more likely to report family history of dementia (OR=2.09), without significant differences in Parkinson’s disease or sleep disorders. Medication exposures and medical history were similar between groups. Autonomic and motor symptoms were more common among those who converted. Risk factors for primary dementia and parkinsonism were generally similar, except for a notably higher clonazepam use in dementia convertors (OR=2.6). Interpretation Patients with idiopathic RBD are at very high risk of neurodegenerative synucleinopathy. Risk factor profiles between convertors and non-convertors have both important commonalities and differences.

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Idiopathic rapid eye movement sleep behaviour disorder is characterized by nocturnal violence, increased muscle tone during rapid eye movement sleep and the lack of any other neurological disease. However, idiopathic rapid eye movement sleep behaviour disorder can precede parkinsonism and dementia by several years. Using 3 T magnetic resonance imaging and neuromelanin-sensitive sequences, we previously found that the signal intensity was reduced in the locus coeruleus/subcoeruleus area of patients with Parkinson's disease and rapid eye movement sleep behaviour disorder. Here, we studied the integrity of the locus coeruleus/subcoeruleus complex with neuromelanin-sensitive imaging in 21 patients with idiopathic rapid eye movement sleep behaviour disorder and compared the results with those from 21 age- and gender-matched healthy volunteers. All subjects underwent a clinical examination, motor, cognitive, autonomous, psychological, olfactory and colour vision tests, and rapid eye movement sleep characterization using video-polysomnography and 3 T magnetic resonance imaging. The patients more frequently had preclinical markers of alpha-synucleinopathies, including constipation, olfactory deficits, orthostatic hypotension, and subtle motor impairment. Using neuromelanin-sensitive imaging, reduced signal intensity was identified in the locus coeruleus/subcoeruleus complex of the patients with idiopathic rapid eye movement sleep behaviour. The mean sensitivity of the visual analyses of the signal performed by neuroradiologists who were blind to the clinical diagnoses was 82.5%, and the specificity was 81% for the identification of idiopathic rapid eye movement sleep behaviour. The results confirm that this complex is affected in idiopathic rapid eye movement sleep behaviour (to the same degree as it is affected in Parkinson's disease). Neuromelanin-sensitive imaging provides an early marker of non-dopaminergic alpha-synucleinopathy that can be detected on an individual basis.

Patients with Parkinson's disease (PD) often complain of unsteadiness. This can occur as the result of various neurological dysfunctions, including changes in postural adjustments, loss of postural reflexes, axial akinesia and rigidity, freezing and/or postural hypotension. In some cases these symptoms remain unexplained, and rare cases of unsteadiness have been attributed to tremor on standing. To delineate this condition, we investigated 11 consecutive PD patients with unexplained unsteadiness because of tremor on standing, seen in our department over a 6-year period. All the patients had detailed clinical and electrophysiological investigations based on surface polygraphic electromyographic recordings. Four patients had fast orthostatic tremor (13-18 Hz), one had intermediate orthostatic tremor (8-9 Hz), and three had slow orthostatic tremor (4-6 Hz). The remaining 3 patients had orthostatic myoclonus, a condition that has not previously been reported in PD. Patients with fast tremor improved on clonazepam. Patients with slow tremor and myoclonus improved on levodopa and sometimes benefited further when clonazepam was added. These observations show the usefulness of neurophysiological investigations for diagnosing and treating unexplained unsteadiness in Parkinson's disease.

Narcolepsy is a novel, easy model for studying lucid dreaming.

SUMMAR Y Patients with idiopathic hypersomnia never feel fully alert despite a normal or long sleep night. The spectrum of the symptoms is insufficiently studied. We interviewed 62 consecutive patients with idiopathic hypersomnia (with a mean sleep latency lower than 8 min or a sleep time longer than 11 h) and 50 healthy controls using a questionnaire on sleep, awakening, sleepiness, alertness and cognitive, psychological and functional problems during daily life conditions. Patients slept 3 h more on weekends, holidays and in the sleep unit than on working days. In the morning, the patients needed somebody to wake them, or to be stressed, while routine, light, alarm clocks and motivation were inefficient. Three-quarters of the patients did not feel refreshed after short naps. During the daytime, their alertness was modulated by the same external conditions as controls, but they felt more sedated in darkness, in a quiet environment, when listening to music or conversation. Being hyperactive helped them more than controls to resist sleepiness. They were more frequently evening-type and more alert in the evening than in the morning. The patients were able to focus only for 1 h (versus 4 h in the controls). They complained of attention and memory deficit. Half of them had problems regulating their body temperature and were near-sighted. Mental fatigability, dependence on other people for awakening them, and a reduced benefit from usually alerting conditions (except being hyperactive or stressed) seem to be more specific of the daily problems of patients with idiopathic hypersomnia than daytime sleepiness.k e y w o r d s fatigue, hypersomnia, long sleep time, mental fatigability, sleep drunkenness, sleepiness, tiredness