Excessive daytime sleepiness in Parkinson's disease: the key is beyond sleep macrostructure.

Abstract

The so-called “non-motor symptoms” are present in almost all patients with Parkinson’s disease (PD), and sleep disorders are among the most common ones [1, 2]. Excessive daytime sleepiness (EDS), defined as the difficulty to remain awake and alert during the day and/or sleep attacks (unintended and inappropriate episodes of falling sleep with minimal or no prodromes of drowsiness), affects a large portion of patients with PD, ranging from 20% to 75% [3–5]. This wide range depends on both the personal ability of the patient and/or the caregiver to recognize and report EDS and the methods used for its evaluation. EDS significantly impairs the quality of life of patients with PD and its disabling consequences include undesired sleep episodes, reduced attention, cognitive impairment, depressed mood, increased accidents, decreased productivity, and worsening of motor function [6–8]. EDS is often multifactorial in etiology, which complicates its treatment. Comorbid sleep disorders, older age, advanced PD stage, presence of autonomic dysfunction, and psychiatric comorbidities are all the multiple factors implicated as possible causes of EDS [9–11].