Introduction: Disrupted sleep and excessive daytime sleepiness (EDS) are common and disabling symptoms of Parkinson's disease (PD). The relationships between subjective and objective assessments of sleep and sleepiness in PD are not well established. We aimed to examine the relationships between self-reported (subjective) and objective assessments of sleep and sleepiness in PD.
Methods: Epworth Sleepiness Scale (ESS), Pittsburg Sleep Quality Index (PSQI), Parkinson's Disease Sleep Scale (PDSS), sleep diaries, and overnight polysomnography (PSG) with next-morning multiple sleep latency testing (MSLT) were collected from 27 individuals with PD and EDS who participated in a clinical trial of light therapy for EDS in PD.
Results: No significant correlations were found between measures of EDS and night-time sleep quality and quantity. PDSS was correlated with PSQI. PDSS and PSQI had significant relationships with multiple metrics derived from sleep diaries, including sleep latency, quality, and ease of falling asleep. Several PSG-derived sleep metrics correlated well with sleep diary metrics.
Conclusions: There is a poor correlation between metrics used to assess sleep and sleepiness in PD. A sleep diary may be a valuable tool for this purpose. Accurate clinical and research assessment and monitoring require refinement of existing and development of novel methods for measuring sleep and sleepiness in PD.
Keywords: Parkinson's disease; Sleep; Sleep diary; Sleepiness.
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