Characterization of the Involvement of the Subthalamic Nucleus During Wakefulness and Sleep in Parkinson's Disease: Contribution of Deep Brain Stimulation

Overview

Sleep-wake disturbances are common in Parkinson's disease. These disturbances are associated with a decline in patients' quality of life and a poor prognosis. This clinical research project follows a study conducted in non-human primates that began in 2017 at the Grenoble Institute of Neuroscience. In this study, the investigators confirmed the existence of sleep-wake behavior disturbances in the macaque model of the disease, and the investigators characterized their nature and expression. These disturbances were founded to be very similar to those observed in patients with Parkinson's disease. The investigators then explored the involvement of different brain structures, potentially targets for deep brain stimulation, in sleep-wake behavior under healthy conditions and dopamine depletion (Parkinson's disease model). Among the deep brain stimulation targets being explored, the subthalamic nucleus (STN), still under investigation in this preclinical program, is a promising candidate for deep brain stimulation because this nucleus is strongly implicated in motor behavior and, more recently, in sleep/wake behavior. An ongoing study in non-human primates shows that it is possible to identify states of alertness based on STN activity, and an automatic detection algorithm is currently being evaluated. Furthermore, this study will allow for the characterization of sleep/wake behavioral disturbances (diurnal and nocturnal) in patients with Parkinson's disease. Finally, this study will enable a correlation analysis between disease severity and sleep/wake disturbances.

The subthalamic nucleus (STN) is a central structure of the basal ganglia circuit. Through its connection to the frontal cortex via the hyperdirect pathway, it is a key indicator of cortical activity, and its stimulation can exert an anterograde influence on the cortex. While the mechanisms of STN deep brain stimulation (DBS) are not yet fully understood, recent studies (see above) have demonstrated that Parkinson's disease (PD) patients with STN implants experience improved sleep. However, this improvement is insufficient to restore more physiological sleep, and further research is needed to develop better management strategies for sleep disorders. In this study, the investigators hypothesize that: 1\) STN activity reflects cortical activity and can therefore detect events characteristic of sleep-wake disorders. 2) Such events detected on the basis of STN activity could allow for a better understanding of the role of the STN in sleep and the development of adaptive DBS targeting sleep disorders in addition to motor disorders. This is a prospective, single-center, open-label pilot study. Patients with Parkinson's disease for whom surgery to implant deep brain stimulation electrodes in the subthalamic nucleus is indicated will be included. These patients will be recruited by the investigators during their follow-up visits to the neurosurgery department of Grenoble Alpes University Hospital. In addition to providing a better understanding of how deep brain stimulation of the subthalamic nucleus impacts sleep/wake behavior, this study will allow for a more precise investigation of the subthalamic nucleus's involvement in the pathophysiology of sleep/wake behavior disorders in patients with Parkinson's disease. These results could then lead to the development of adaptive stimulation, triggered according to markers of sleep and wakefulness disorders.