Catch those zzzz’s: Sleep and cognition in Parkinson’s disease

This study investigated the effects of sleep disorders on memory and executive function in patients with Parkinson’s disease (PD). The authors concluded that poor sleep was associated with memory and executive function in patients with PD.

In addition to problems with co-ordination and movement (motor function), PD patients can experience non-motor symptoms, such as sleep disorders. Sleep problems affect up to 98% of those with PD and can have a negative effect on quality of life. Some of these disorders include insomnia (inability to sleep) and sleep-related breathing disorders (SRBD).

Sleep disorders or poor sleep can lead to cognitive dysfunction in the general population. Cognitive dysfunction can include problems with memory and executive function (control of  concentration, decision-making, attention). It is unclear if sleep disorders causes similar problems with cognition (memory) and executive function in patients with PD.

This study reviewed data from 16 clinical reports, including 1882 patients with PD and sleep disorders. In these studies, patients were assessed using several different tests to determine cognitive function. 

Poor sleep significantly affected overall cognitive function and memory in patients with PD. Tasks involved in executive function appeared to be most affected.

This study concluded that sleep problems in patients with Parkinson's disease was associated with poorer cognitive performance that those who do not have sleep problems. 

The methods used in these studies varied and the effects seen were driven by a small number of the studies included. Further studies are needed larger populations and standardized methods to investigate sleep and cognitive function in PD.

This study did not determine that poor sleep directly caused cognitive problems, but instead found an association. Further studies are needed to determine the cause.