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Updated: Aug 5, 2026

Association Between Sleep Quality and Cognitive Symptoms in Patients with Major Depressive Disorder
Published on: April 26, 2024
The Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale in frontotemporal dementia and Alzheimer's disease
Jessica Jiang1, Eva K Larsen1, Benjamin A Levett1
1Dementia Research Centre, Queen Square Institute of Neurology, University College London, London, England, UK.
Introduction:
Sleep disturbance is common in dementia, impacting daytime function and care. Compared with Alzheimer's disease (AD), sleep in frontotemporal dementia (FTD) is poorly characterized.
Methods:
We assessed sleep using the Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index in 58 people with primary progressive aphasia (PPA) and right temporal variant FTD, 32 with AD, and 36 cognitively healthy older volunteers. All participants had cognitive and behavioral assessments. Groups were compared using non-parametric statistics and correlations assessed sleep versus other indices.
Results:
Subjective sleep duration was increased in all syndromic groups. AD and semantic PPA were associated with increased daytime somnolence. Reported sleep quality varied between syndromes. Across the disease cohort, somnolence correlated with behavioral and empathy deficits; in AD, poorer sleep quality correlated additionally with self-monitoring deficits.
Discussion:
FTD and AD syndromes have distinct sleep phenotypes, and sleep alterations are associated with behavior. Standard sleep scales require careful interpretation in dementia.
