Cognitive Behavioral Therapy for Insomnia in Neurodegenerative Disorders: Targeting Sleep Disturbances in Alzheimer's and Parkinson's Disease: A scoping review

Desirèe Latella¹Andrea Calderone^1*Carmela Casella²Rosaria De Luca¹Antonio Gangemi¹Federica Impellizzeri¹Santina Caliri¹Angelo Quartarone¹Rocco Salvatore Calabrò¹

• ¹IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
• ²Azienda Ospedaliera Universitaria G Martino di Messina, Messina, Italy

Word count: 291 Insomnia is highly prevalent in neurodegenerative disorders, yet pharmacological options carry safety 16 and tolerability concerns. This scoping review (code/number: DOI 10.17605/OSF.IO/8VP3F) mapped 17 contemporary evidence for cognitive behavioral therapy for insomnia (CBT-I) across Alzheimer's 18 disease (AD), mild cognitive impairment (MCI), and Parkinson's disease (PD). Following a 19 preregistered protocol, we searched PubMed, Cochrane Library, Web of Science, and Scopus (2015– 20 2025), screened English-language studies in adults, and applied dual independent review with 21 consensus resolution. Of 105 records, 70 were screened after deduplication and 8 met eligibility 22 criteria. Across randomized trials, pilot and feasibility studies, and single-case experimental designs, 23 CBT-I, delivered in person or via telehealth, consistently reduced insomnia severity and improved 24 sleep quality, with frequent ancillary gains in mood, anxiety, and daytime functioning. Remote and 25 digitally augmented delivery appeared feasible and acceptable for cognitively vulnerable adults and 26 caregivers. Early signals suggested potential cognitive benefits in prodromal populations (AD/MCI), 27 and exploratory observations linked improved sleep with plausible neurobiological mechanisms such 28 as amyloid beta dynamics. In PD, findings also aligned with a mechanistic pathway in which presleep 29 cognitive arousal, safety behaviors, and dysfunctional sleep beliefs are modifiable targets. Non-30 pharmacological comparators (for example, mindfulness, therapeutic exercise, neuromodulation) 31 showed benefits that contextualize where CBT-I may offer disorder-relevant leverage on insomnia 32 outcomes. The overall strength of evidence is tempered by small samples, heterogeneity in comparators 33 and dosing, short follow-up, and inconsistent reporting of clinically meaningful change. Priorities 34 include multicenter randomized trials with standardized sleep and cognitive endpoints, longer 35 observation, head-to-head comparative effectiveness with economic evaluation, adaptive protocols 36 tailored to PD-specific disruptors, and mechanistic studies integrating digital phenotyping and 37 biomarkers to test durability and downstream clinical impact.