REM Sleep Behavior Disorder Linked to Cognitive Decline

A cross-sectional study published in npj Parkinson's Disease has reported a significant association between isolated REM sleep behavior disorder (iRBD) and subjective cognitive decline (SCD). The study, conducted by researchers at the Faculty of Medicine and University Hospital Cologne, found that individuals with iRBD were more likely to experience SCD, which may be an early marker of mild cognitive impairment (MCI). The research highlights the need for further investigation into the prognostic value of SCD in iRBD.

Key Takeaways:

• The study involved 80 individuals with iRBD, who were classified into three groups based on neuropsychological testing and the Multi-SubCoDE questionnaire: iRBD with MCI (RBD.MCI), with SCD (RBD.SCD+), and without both (RBD.SCD-).
• The prevalence of SCD in iRBD was found to be 36.3%, with predominance of the amnestic multi-domain SCD profile.
• Individuals with RBD.SCD+ reported more severe depressive symptoms and lower cognitive performance than those with RBD.SCD-.
• Magnetic resonance imaging analyses revealed lower grey matter volume in the left superior frontal gyrus for RBD.SCD+ compared to RBD.SCD-.
• The study found a significant association between SCD and subtle cognitive deficits and structural brain changes in individuals with iRBD.

Statistics:

• 36.3% of individuals with iRBD experienced SCD.
• 56.3% of individuals with SCD had the amnestic multi-domain SCD profile.
• The grey matter volume in the left superior frontal gyrus was 12.5% lower in individuals with RBD.SCD+ compared to RBD.SCD-.
• 70% of individuals with RBD.SCD+ reported more frequent depressive symptoms.

Sources:

• npj Parkinson's Disease
• Faculty of Medicine and University Hospital Cologne
• Mental Health Weekly Digest (October 20, 2025, p 392)