Sleep-like brain waves during wakefulness linked to Parkinson's symptoms

A new study shows that slow brain waves – typically associated with deep sleep or a sleep-like state – are more frequent during wakefulness in patients with Parkinson's disease and correlate with symptoms such as hallucinations and impaired cognition. The findings cast light on the link between brain waves, daytime sleepiness, and core features of Parkinson's disease – an important topic in neurodegenerative research.

Slow waves typically appear in healthy people during sleep, although sometimes they can briefly manifest when awake during mind-wandering or daytime sleepiness. Research shows that slow waves are altered during sleep in patients with neurodegenerative diseases such as Parkinson's disease, who tend to experience poorer sleep quality and excessive daytime sleepiness. However, it is still an open question whether patients with Parkinson's disease also display unusual patterns in the sleep-like slow waves that can appear during the daytime.

Seeking insight, Fosco Bernasconi and colleagues performed electroencephalography to record the brain's activity in 84 patients with Parkinson's disease and 30 healthy elderly participants. They observed that the patients experienced more daytime sleepiness and displayed a higher number of sleep-like slow waves per minute than the control group. Furthermore, the amplitude of the waves was greater in patients with Parkinson's disease who experienced minor hallucinations, and also correlated with poorer cognitive function as measured with a clinical scoring system. "Future studies should investigate whether [sleep-like slow wave] alterations are already present at a prodromal stage of [Parkinson's disease]," Bernasconi et al. write, adding that slow wave patterns might offer a way to identify people at risk of the condition.