P51-S Oscillatory activity in motor episodes of REM sleep behaviour disorder

Background REM sleep behavior disorder (RBD) is a parasomnia, characterized by motor conducts that evoke the content of dreams and its association with alpha-synucleinopathies is well established. Little is known about the part that the cerebral cortex plays in its pathophysiology. Differences in movement-related cortical activity have been described between PD patients and controls and motor symptoms and signs of PD patients “disappear” in RBD during motor episodes while in REM sleep. Therefore the study of movement-related cortical changes during RBD between patients with and without Parkinson’s Disease might help understand these phenomena. Materials and Methods Polysomnographic studies from patients diagnosed with RBD were analyzed, 7 with Parkinson’s Disease and 8 without motor alterations, selecting fragments with the presence of limb movements. The cortical activity in temporal relationship to these movements was evaluated through time frequency transforms and statistical analyses. Results Our analyses showed a desynchronization of alpha and beta activity (10–30 Hz) that began shortly before the onset of the movement, and was followed by a post-movement synchronization in the 10–20 Hz range. An increase in gamma activity around 40 Hz was also observed during movement. No statistical differences were found between the two groups in our study. Conclusions The cortical activity associated with limb movements in RBD motor episodes possesses a similar configuration to the signal detected in relation to movements performed under circumstances such as wakefulness. This finding supports the participation of the primary motor cortex in RBD, with or without Parkinson’s Disease.