Lack of Association between Impulse Control Disorders and REM Sleep Behavior Disorder in Patients with Parkinson’s Disease

Purpose: Rapid eye movement sleep behavior disorder (RBD) and impulse control disorders (ICDs) are common in subjects with Parkinson’s disease. The association between these two conditions has been contradictory. The aim of this study is to analyze the association between these two non-motor symptoms. Methods: Consecutive subjects with Parkinson’s disease attending the Movement Disorders Outpatient Clinic were included. The presence of ICDs was assessed using the Questionnaire for Impulse Control Disorders Rating Scale. RBD was diagnosed by an overnight, single night polysomnography. Results: Fifty-five consecutive subjects with Parkinson’s disease were included. The prevalence of ICDs and related behaviors was 23.6% (ICD in 14.5% and related behaviors in 9.1%). RBD was diagnosed in 47.2% of the patients. No differences were found in the frequency of ICDs and related behaviors when comparing subjects with and without RBD (23% versus 24.1%, p = 0.926, respectively). Conclusion: No association between the presence of RBD and the frequency of ICDs in subjects with Parkinson’s disease was found.

Perchance to dream? Primordial motor activity patterns in vertebrates from fish to mammals: their prenatal origin, postnatal persistence during sleep, and pathological reemergence during REM sleep behavior disorder

An overview is presented of the literature dealing with sleep-like motility and concomitant neuronal activity patterns throughout the life cycle in vertebrates, ectothermic as well as endothermic. Spontaneous, periodically modulated, neurogenic bursts of non-purposive movements are a universal feature of larval and prenatal behavior, which in endothermic animals （i.e. birds and mammals） continue to occur periodically throughout life. Since the entire body musculature is involved in ever-shifting combinations, it is proposed that these spontaneously active periods be designated as ＇rapid-BODY-movement＇ （RBM） sleep. The term ＇rapid-EYE- movement （REM） sleep＇, characterized by attenuated muscle contractions and reduced tonus, can then be reserved for sleep at later stages of development. Mature stages of development in which sustained muscle atonia is combined with ＇paradoxical arousal＇ of cortical neuronal firing patterns indisputably represent the evolutionarily most recent aspect of REM sleep, but more research with ectothermic vertebrates, such as fish, amphibians and reptiles, is needed before it can be concluded （as many prematurely have） that RBM is absent in these species. Evidence suggests a link between RBM sleep in early development and the clinical condition known as ＇REM sleep behavior disorder （RBD）＇, which is characterized by the resurgence of periodic bouts of quasi-fetal motility that closely resemble RBM sleep. Early developmental neuromotor risk factors for RBD in humans also point to a relationship between RBM sleep and RBD.

Premotor Diagnosis of Parkinson's Disease

Typical Parkinsonian symptoms consist of bradykinesia plus rigidity and/or resting tremor. Some time later postural instability occurs. Pre-motor symptoms such as hyposmia, constipation, REM sleep behavior disorder and depression may antecede these motor symp- toms for years. It would be ideal, if we had a biomarker which would allow to predict who with one or two of these pre-motor symptoms will develop the movement disorder Parkinson＇s disease （PD）. Thus, it is interesting to learn that biopsies of the submandibular gland or colon biopsies may be a means to predict PD, if there is a high amour of abnormally folded alpha-synuclein and phosphorylated alpha-synuclein. This would be of relevance if we would have available means to stop the propagation of abnormal alpha-synuclein which is otherwise one of the reasons of this spreading disease PD.

Recent Progress in Non-motor Features of Parkinson’s Disease with a Focus on Circadian Rhythm Dysregulation

Parkinson’s disease(PD)is the second most common neurodegenerative disease,which manifests with both motor and non-motor symptoms.Circadian rhythm dysregulation,as one of the most challenging non-motor features of PD,usually appears long before obvious motor symptoms.Moreover,the dysregulated circadian rhythm has recently been reported to play pivotal roles in PD pathogenesis,and it has emerged as a hot topic in PD research.In this review,we briefly introduce the circadian rhythm and circadian rhythm-related genes,and then summarize recent research progress on the altered circadian rhythm in PD,ranging from clinical features to the possible causes of PD-related circadian disorders.We believe that future comprehensive studies on the topic may not only help us to explore the mechanisms of PD,but also shed light on the better management of PD.