Jester DJ, et al. - Via performing this systematic review, researchers consolidated the most recent literature on neuropsychological deficits in adults with Parkinson disease who endure excessive daytime sleepiness (EDS). In addition, they addressed confounds and methodological limitations. Proposal of a framework entitled the Cascade Model of Excessive Daytime Sleepiness (CMEDS) was made to define the role of EDS attributing to cognitive impairment for patients with Parkinson disease. Systematic search through PubMed, PsychInfo and citation records yielded eight studies with 1,373 patients for inclusion; 442 of the patients had Parkinson disease with EDS. As per the analysis, Parkinson disease patients suffering from EDS may exhibit global additional cognitive deficits, in executive control, and in processing speed. The CMEDS framework indicates that EDS influences cognition in relation to Parkinson disease pathology, comorbidities, and medication use.