Les comportements oniriques et leurs caractéristiques lors de la maladie de Parkinson

Dynamic networks of cortico-muscular interactions in sleep and neurodegenerative disorders

The brain plays central role in regulating physiological systems, including the skeleto-muscular and locomotor system. Studies of cortico-muscular coordination have primarily focused on associations between movement tasks and dynamics of specific brain waves. However, the brain-muscle functional networks of synchronous coordination among brain waves and muscle activity rhythms that underlie locomotor control remain unknown. Here we address the following fundamental questions: what are the structure and dynamics of cortico-muscular networks; whether specific brain waves are main network mediators in locomotor control; how the hierarchical network organization relates to distinct physiological states under autonomic regulation such as wake, sleep, sleep stages; and how network dynamics are altered with neurodegenerative disorders. We study the interactions between all physiologically relevant brain waves across cortical locations with distinct rhythms in leg and chin muscle activity in healthy and Parkinson's disease (PD) subjects. Utilizing Network Physiology framework and time delay stability approach, we find that 1) each physiological state is characterized by a unique network of cortico-muscular interactions with specific hierarchical organization and profile of links strength; 2) particular brain waves play role as main mediators in cortico-muscular interactions during each state; 3) PD leads to muscle-specific breakdown of cortico-muscular networks, altering the sleep-stage stratification pattern in network connectivity and links strength. In healthy subjects cortico-muscular networks exhibit a pronounced stratification with stronger links during wake and light sleep, and weaker links during REM and deep sleep. In contrast, network interactions reorganize in PD with decline in connectivity and links strength during wake and non-REM sleep, and increase during REM, leading to markedly different stratification with gradual decline in network links strength from wake to REM, light and deep sleep. Further, we find that wake and sleep stages are characterized by specific links strength profiles, which are altered with PD, indicating disruption in the synchronous activity and network communication among brain waves and muscle rhythms. Our findings demonstrate the presence of previously unrecognized functional networks and basic principles of brain control of locomotion, with potential clinical implications for novel network-based biomarkers for early detection of Parkinson's and neurodegenerative disorders, movement, and sleep disorders.

Early onset of sleep/wake disturbances in a progressive macaque model of Parkinson's disease

Parkinsonian patients often experience sleep/wake disturbances, which may appear at an early stage of the disease; however, these disturbances have not been fully described. To better understand the evolution of these disturbances with respect to disease progression, we aimed to characterize these clinical signs in a progressive nonhuman primate model of Parkinson's disease. Three adult macaques (Macaca fascicularis) were equipped with a polysomnographic telemetry system allowing the characterization of sleep/wake behavior via long-term neurophysiological recordings and underwent a modified multiple sleep latency test. Experiments were first performed in a healthy state and then during the progressive induction of a parkinsonian syndrome by intramuscular injections of low doses of MPTP. We observed an early onset of significant sleep/wake disturbances (i.e., before the appearance of motor symptoms). These disturbances resulted in (i) a disorganization of nighttime sleep with reduced deep sleep quality and (ii) an excessive daytime sleepiness characterized by sleep episodes occurring more rapidly in the morning and spreading through the middle of the day. The present study suggests that nighttime and daytime sleep/wake disturbances may appear early in the disease and should be considered in the development of biomarkers in further studies.

Comorbid Sleep Disturbances in Neurologic Disorders

PURPOSE OF REVIEW

This article provides a review of disturbances of sleep comorbid with common neurologic disorders.

RECENT FINDINGS

A wide variety of neurologic disorders are frequently complicated by comorbid sleep disturbances. In many cases, a bidirectional relationship appears to occur between sleep function and the neurologic disease, such that treatment of comorbid sleep disturbances may improve the symptoms of the neurologic disease.

SUMMARY

Neurologic disorders are often associated with abnormalities of sleep. Sleep influences the severity of both epilepsy and headache, and treatment of comorbid sleep disorders may improve seizure and headache frequency. Alzheimer disease is characterized by circadian phase delay and poor nighttime sleep and is strongly associated with obstructive sleep apnea. Parkinson disease is associated with several sleep disorders, including insomnia, restless legs syndrome, rapid eye movement (REM) sleep behavior disorder, daytime hypersomnia, and sleep-disordered breathing. Hypoventilation in amyotrophic lateral sclerosis and other neuromuscular disorders often presents initially with sleep problems, and treatment with noninvasive ventilation improves survival and quality of life.

Non-motor signs in patients with Parkinson's disease at the University Hospital of Point "G", Mali

Introduction

Despite significant progress in the field of scientific research on Parkinson's disease (PD), the prevalence and pathophysiology of its non-motor signs remains less understood than the classic motor signs of bradykinesia, rigidity, tremor and postural instability. Data covering this topic are rare in Africa, and almost non-existent in sub-Saharan Africa. Thus, this study aims to highlight the frequency of certain non-motor signs in PD patients followed in the Department of Neurology of the University Hospital Point “G”, Bamako, Mali.

Methodology

This is a retrospective and descriptive study from January 2012 to November 2013. We identified records of patients with dopamine-responsive idiopathic Parkinson's disease, and quantified associated non-motor symptoms. Data were analyzed with Epi-Info 2000 version 3.5.5.

Result

During this period we reviewed 60 patient charts of which 68.3% were men. The average age of patients was 66.51 ranging from 25 to 94 years.

Non-motor symptoms were present in 90% of cases, including sensitive disorders in 76.7%, dysautonomia in 73.3%, and psycho-behavioral disorders, including sleep disorders, in 81.7%.

Conclusion

At the end of this study, we observed an important place for non-motor signs in the clinical manifestation of PD patients in general.