Complex paroxysmal nocturnal behaviors in Parkinson's disease.

Complex paroxysmal nocturnal motor behavioral disorders (CPNBs) are frequently reported in patients with Parkinson's disease (PD). REM sleep behavior disorder (RBD) is reported in at least a third of PD patients, although CPNB episodes can also occur on arousal from NREM sleep. It is important to establish the nature of CPNBs occurring in PD, as the different types have different neurobiological significance and clinical importance, and also different treatments. Ninety-six PD patients with and without CPNBs were submitted to overnight in-hospital video-polysomnography. Of these, 76 (47 men) were included in the study analysis: these were patients in whom it was possible to establish the presence or absence of CPNBs and to obtain a clear-cut diagnosis of the nature of the CPNBs reported. The CPNBs were found to be RBD episodes in 39 cases (87%) and nonRBD episodes in 6 (13%) (arousal-related episodes arising from NREM sleep in 3 cases and from REM sleep in 2 cases, parasomnia overlapping syndrome in 1 case). In 4 of the 6 subjects with nonRBD episodes, these occurred upon arousal at the end of an obstructive apnoeic event. Our data confirm that CPNBs in PD are, in most cases, RBD episodes. However, arousal-related episodes accounted for 13% of the CPNBs observed in our sample and occurred in close temporal association with sleep-disordered breathing (SDB). The arousal system is defective in extrapyramidal diseases due to neurodegenerative changes involving the brain stem reticular network; against this background, a trigger effect of SDB on CPNBs, through induction of abrupt arousal, may be hypothesized.