Dementia / Alzheimer Disease / Sleep Wake Disorders · Journal article

Comparison of sleep characteristics between Alzheimer's disease dementia and Parkinson's disease dementia.

Sleep Medicine · July 14, 2026

Strong Evidence Why this matters to you Expert discussion

Well-designed and adequately powered for the question it asks.

AI Summary

In a comparative cohort of 105 AD and 104 PDD patients, despite similar global PSQI scores, PDD was independently associated with poorer subjective sleep quality, higher daytime nap frequency, and markedly elevated RBD prevalence. A combined sleep profile discriminated PDD from AD with an AUC of 0.763, suggesting distinct sleep phenotypes despite similar overall sleep burden.

What was studied

Prospective cross-sectional comparative cohort study. Consecutive patients from a memory clinic with AD dementia (n=105) or PDD (n=104).. Intervention: Comparison of sleep characteristics between two dementia phenotypes; no intervention applied.. Compared with: Alzheimer's disease dementia (AD) as the reference group for PDD.. n = 209. Single memory clinic; specific location not stated in source text..

Key findings

PDD remained independently associated with poorer sleep quality after full adjustment (B = 0.355, 95% CI: 0.092–0.619, p = 0.008) PDD independently associated with higher daytime nap frequency (B = 2.124, 95% CI: 1.327–2.920, p < 0.001) RBD much higher in PDD after adjustment (OR = 18.482, 95% CI: 3.297–103.603, p = 0.001)

Safety

Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.

Who this may help

Clinicians managing dementia patients should recognize that AD and PDD present distinct sleep profiles despite similar overall PSQI scores; assessment of subjective sleep quality, daytime napping, and RBD may help differentiate PDD from AD and guide targeted sleep interventions.

Plain-language summary

A well-designed comparative study with multivariable adjustment across two dementia cohorts identifies independent sleep phenotype differences with quantified effect sizes and confidence intervals.

Study design

As stated by the source record.

MethodsConsecutive enrollment of 105 AD and 104 PDD patients from a memory clinic. Both groups underwent standardized assessments including global cognition (MMSE, MoCA), activities of daily living (ADL), anxiety and depression (HAMA, HAMD), and sleep characteristics using validated instruments (PSQI, RBD assessment, daytime nap questionnaire, Epworth Sleepiness Scale). Multivariable regression analyses examined independent associations between group membership and sleep dimensions after adjustment for covariates. ROC curves evaluated combined sleep items' discriminative performance.

DesignProspective cross-sectional comparative cohort study

PopulationConsecutive patients from a memory clinic with AD dementia (n=105) or PDD (n=104).

Sample size209

InterventionComparison of sleep characteristics between two dementia phenotypes; no intervention applied.

ComparatorAlzheimer's disease dementia (AD) as the reference group for PDD.

SettingSingle memory clinic; specific location not stated in source text.

Reported figures

Quoted from the source exactly as published.

Sample size (AD)105

Sample size (PDD)104

Sleep quality—adjusted coefficient (B)0.355

Sleep quality—95% CI0.092–0.619

Sleep quality—p-value0.008

Daytime nap frequency—adjusted coefficient (B)2.124

Daytime nap frequency—95% CI1.327–2.920

Daytime nap frequency—p-value< 0.001

Clinical bottom line

Caveats

Single-center study; generalizability to other memory clinic or community settings unclear.
Cross-sectional design precludes causal inference about disease-specific sleep mechanisms.
No data on treatment effects or longitudinal sleep trajectory within each disease group.
ROC analysis uses post-hoc combination of items; validation in independent cohort not reported.

Evidence assessment

Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.

Study design

strong

Prospective consecutive enrollment with standardized validated instruments across both groups.

Directness

strong

Sleep characteristics directly measured in target populations; clinically relevant endpoints.

Consistency

moderate

Single center study; findings support distinction between AD and PDD but require replication.

Risk of bias

moderate

No blinding or control for unmeasured confounders; cross-sectional design limits causal inference.

Sample adequacy

strong

209 total participants; adequate for multivariable regression with adjustment for multiple covariates.

Source abstract

Background. Alzheimer's disease (AD) dementia and Parkinson's disease dementia (PDD) both frequently involve sleep disturbances, but the characteristics of sleep disruption differ between the two patient groups, and the extent of these differences remains unclear.Methods. We consecutively enrolled 105 patients with AD and 104 with PDD from a memory clinic. All participants underwent assessments of global cognition (MMSE, MoCA), daily living (ADL), anxiety and depression (HAMA, HAMD), and sleep characteristics (PSQI, RBD, daytime nap questionnaire, Epworth Sleepiness Scale). Multivariable regression analyses were conducted to examine whether sleep characteristics differed independently between the two groups. ROC curves evaluated discriminative performance.Results. Global PSQI scores did not differ between the two groups. In univariate analyses, PDD patients reported worse subjective sleep quality (the first PSQI component), more sleep disturbances, greater use of hypnotics, higher daytime nap frequency and duration, and a much higher prevalence of RBD. After full adjustment, PDD remained independently associated with poorer sleep quality (B = 0.355, 95% CI: 0.092-0.619, p = 0.008), higher daytime nap frequency (B = 2.124, 95% CI: 1.327-2.920, p < 0.001), and RBD (OR = 18.482, 95% CI: 3.297-103.603, p = 0.001). A combination of sleep items (sleep quality, nap frequency, RBD) distinguished PDD from AD with an AUC of 0.763.Conclusions. Despite a comparable total PSQI score, PDD patients showed significantly poorer sleep quality (the first PSQI component), more frequent daytime napping, and a much higher prevalence of RBD compared with AD patients. Subjective sleep profiling may help to understand the differential sleep burden in these common dementias.

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Hongmei CaoDementiaBeiyu ZhaoAlzheimer DiseaseSleep Wake DisordersMeng ZhangRong ZhouXiaojuan GuoSuhang ShangParkinson Disease