深い睡眠中の脳波がアルツハイマー病を防ぐ可能性、新研究が示す(Deep sleep brain waves offer protection against Alzheimer’s disease, new research shows)

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2026-08-25 カナダ・コンコルディア大学

カナダ・コンコルディア大学を中心とする国際研究チームは、アルツハイマー病における認知機能低下と、覚醒・睡眠移行に関わる神経伝達物質オレキシン、睡眠中の脳波との関係を明らかにした。軽度から中等度のアルツハイマー病患者60人を3年間追跡した結果、脳脊髄液中のオレキシン濃度が高い人ほど、記憶・思考能力の低下や行動・精神症状、神経変性・炎症の生物学的指標が強い傾向を示した。一方、ノンレム睡眠中に生じる睡眠紡錘波や徐波振動が強い人では、この悪影響が軽減され、認知機能低下が比較的小さかった。研究者らは、こうした睡眠脳波が神経の「レジリエンス」を高め、オレキシン過剰による認知への悪影響を抑える可能性を指摘している。睡眠脳波やオレキシン濃度をアルツハイマー病の進行評価に利用し、睡眠を標的とした治療につなげられる可能性がある。

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アルツハイマー病におけるオレキシン、睡眠、認知機能:ノンレム睡眠時の振動活動と神経回復力 Orexin, Sleep, and Cognition in Alzheimer Disease Non-REM Oscillatory Activity and Neural Resilience

Arsenio Paez, Gerard Piñol-Ripoll, Anna Carnes-Vendrell, Farida Dakterzada, Ferran Barbé, Henrik Zetterberg, and Thien Thanh Dang-Vu
Neurology  Published:August 11, 2026
DOI:https://doi.org/10.1212/WNL.0000000000218307

深い睡眠中の脳波がアルツハイマー病を防ぐ可能性、新研究が示す(Deep sleep brain waves offer protection against Alzheimer’s disease, new research shows)

Abstract

Background and Objectives
Sleep-wake dysregulation and elevated CSF orexin have been implicated in Alzheimer disease (AD). Sleep spindles (SPs) and slow oscillations (SOs) are linked to cognition and neurodegeneration; however, their relationship with CSF orexin concentrations in symptomatic AD has not been characterized. We investigated whether nonrapid eye movement (NREM) SP-SO activity is associated with CSF orexin and whether these oscillatory features moderate associations between orexin, cognition, neuropsychiatric symptom severity, and AD biomarkers.

Methods
This prospective observational cohort study was conducted at a tertiary memory clinic in Lleida, Spain. Individuals aged ≥60 years with biomarker-confirmed mild-to-moderate AD (National Institute on Aging-Alzheimer’s Association criteria) underwent overnight polysomnography and morning CSF sampling. SP and SO were detected using validated automated algorithms with independent verification and visual quality control. CSF was assayed for orexin-A, amyloid-β42 (Aβ42), phosphorylated tau181 (pTau181), total tau, and YKL-40. Cognitive performance Alzheimer’s Disease Assessment Scale–Cognitive Subscale ([ADAS-Cog], Mini-Mental State Examination (MMSE), California verbal learning test, ROCF) and neuropsychiatric symptoms (NPI) were assessed longitudinally over 36 months. Associations were examined using generalized linear models with robust estimators adjusted for age, sex, Aβ42, and apnea-hypopnea index. Multiple comparisons were controlled using false discovery rate correction. Interaction terms assessed moderation effects.

Results
Sixty participants (30 women; mean age 74.7 years) were included. Longer SO duration and higher SP density and power were associated with lower CSF orexin concentrations (SP density: β = −187.37 pg/mL, 95% CI −344.93 to −29.80). Orexin was not associated with global sleep continuity metrics. Higher CSF orexin concentrations were associated with worse global cognition (ADAS-Cog: β = 0.014, 95% CI 0.003–0.024; MMSE: β = −0.01, 95% CI −0.011 to −0.004) and greater neuropsychiatric symptom severity (NPI at: β = 0.03, 95% CI 0.011–0.041). Higher orexin was also associated with higher pTau181 (β = 0.11, 95% CI 0.04–0.19), total tau, and YKL-40 (β = 0.37, 95% CI 0.17–0.57). Significant orexin × SP-SO interactions were observed, such that greater oscillatory activity attenuated the adverse associations between orexin and cognitive outcomes, independent of Aβ42 and tau.

Discussion
In biomarker-confirmed AD, NREM SP and SO activity are associated with CSF orexin concentrations and moderate associations between orexin and longitudinal cognitive and neuropsychiatric outcomes. Limitations include the observational design and absence of a comparator group, precluding causal inference and limiting contextualization relative to normal aging. NREM oscillatory metrics and orexin concentrations may represent complementary physiologic markers for disease monitoring and therapeutic targeting.

Trial Registration Information
Role of Hypoxia and Sleep Fragmentation in AD; ClinicalTrials.gov Identifier: NCT02814045.

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