Abstract
Introduction: Sleep and circadian disturbances are highly prevalent among individuals with Alzheimer’s disease (AD) and related dementias, often manifesting years before diagnosis, and could represent a modifiable risk factor for dementia. However, sleep was not formally classified as such in the latest Lancet Commission report of modifiable dementia risk factors. Although there has been a proliferation of research on sleep in the context of aging and dementia over the last decades, consensus guidance is needed to facilitate high-quality research, comparability and consistency. In this context, the Sleep and Circadian Rhythms Professional Interest Area (PIA) of the International Society to Advance Alzheimer’s Research and Treatment (ISTAART) conducted an expert consensus study to establish recommendations to harmonize future research efforts in the field.
Materials and methods: A modified Delphi consensus approach was used to establish recommendations. Between December 2022 and September 2023, a steering committee (SC) of 18 experts in the field of sleep, aging and dementia was constituted by invitation of the 2022-2024 chair of the ISTAART Sleep and Circadian Rhythms PIA (Prof. Sharon Naismith). The SC designed the questions and outcomes of an online survey, and the first voting round was open between November 2023 and February 2024 to all PIA members (n∼480) and non-member researchers. A second online voting round occurred in May 2024 for questions which did not reach consensus in Round 1 or needed clarity, based on the SC’s recommendations. In July 2024, the results were presented to the SC during a virtual meeting. Final recommendations were discussed during the 2024 Alzheimer’s Association International Conference, and were then approved by all SC members.
Results: Forty complete responses were received during the first round of the Delphi process (12 countries; 60% women; mean years of experience in research: 13). Thirty-eight participants agreed to be contacted again for the second Delphi round, and 32 complete responses were received. After two voting rounds, the group determined by consensus: 1) the most relevant sleep and circadian features to assess in the context of aging and dementia research, 2) recommendations on data acquisition and report in older populations with and without cognitive deficits (including on the use of newly-developed wearable and nearable devices), and 3) high-priority future research directions in the field, including which knowledge gaps should be addressed and which sleep and circadian features, populations and designs should be prioritized.
Conclusions: Final consensus recommendations provide guidance to develop high-quality sleep and circadian research in the context of aging and dementia, and synergize future research to improve comparability and clarity within the field. Similar recommendations will need to be established for clinical practice.