Cognitive reserve moderates the relationship between sleep difficulties and executive functions in patients with Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor disturbances as well as non motor symptoms, such as sleep and cognitive difficulties. Recent evidence has shown that, in patients with PD, sleep disturbances selectively correlate with specific cognitive functions, such as non-verbal reasoning, attention and executive functions, and language abilities.The present study aimed to test the hypothesis of Cognitive Reserve (CR) as a potential moderator in the relationship between sleep difficulties and cognitive performance in PD patients. Participants were asked to attend two sessions in which they were assessed for cognitive functions and reserve, as well as subjective sleep quality, excessive sleepiness, and symptoms of REM sleep behavior disorder (RBD) and insomnia.The results of preliminary correlations confirmed the presence of a significant negative correlation between sleep quality and cognitive performance. The results of the moderation analysis revealed a significant role for CR as a moderator of the negative association between RBD and executive functions. Specifically, a significant negative correlation was observed between sleep difficulties and executive performance only in patients with low CR. Overall, our results suggest that patients with PD with low to average CR levels could be considered to be more at risk of developing cognitive deficits in the presence of sleep difficulties.

Automated summary

This study aimed to investigate the moderating role of Cognitive Reserve (CR) in the relationship between sleep difficulties and cognitive performance in patients with Parkinson's disease (PD). The results showed a significant negative correlation between sleep quality and cognitive performance, and CR was found to moderate the negative association between REM sleep behavior disorder (RBD) and executive functions. Patients with low levels of CR were more at risk of developing cognitive deficits in the presence of sleep difficulties.