{"doi":"10.1093/sleep/zsae037","title":"Evaluating a novel 24-hour rest/activity rhythm marker of preclinical β-amyloid deposition","abstract":"STUDY OBJECTIVES: To compare sleep and 24-hour rest/activity rhythms (RARs) between cognitively normal older adults who are β-amyloid-positive (Aβ+) or Aβ- and replicate a novel time-of-day-specific difference between these groups identified in a previous exploratory study. METHODS: We studied 82 cognitively normal participants from the Baltimore Longitudinal Study of Aging (aged 75.7 ± 8.5 years, 55% female, 76% white) with wrist actigraphy data and Aβ+ versus Aβ- status measured by [11C] Pittsburgh compound B positron emission tomography. RARs were calculated using epoch-level activity count data from actigraphy. We used novel, data-driven function-on-scalar regression analyses and standard RAR metrics to cross-sectionally compare RARs between 25 Aβ+ and 57 Aβ- participants. RESULTS: Compared to Aβ- participants, Aβ+ participants had higher mean activity from 1:00 p.m. to 3:30 p.m. when using less conservative pointwise confidence intervals (CIs) and from 1:30 p.m. to 2:30 p.m. using more conservative, simultaneous CIs. Furthermore, Aβ+ participants had higher day-to-day variability in activity from 9:00 a.m. to 11:30 a.m. and lower variability from 1:30 p.m. to 4:00 p.m. and 7:30 p.m. to 10:30 p.m. according to pointwise CIs, and lower variability from 8:30 p.m. to 10:00 p.m. using simultaneous CIs. There were no Aβ-related differences in standard sleep or RAR metrics. CONCLUSIONS: Findings suggest Aβ+ older adults have higher, more stable day-to-day afternoon/evening activity than Aβ- older adults, potentially reflecting circadian dysfunction. Studies are needed to replicate our findings and determine whether these or other time-of-day-specific RAR features have utility as markers of preclinical Aβ deposition and if they predict clinical dementia and agitation in the afternoon/evening (i.e. \"sundowning\").","journal":"SLEEP","year":2024,"id":437874,"datarank":0.3596842909197557,"base_score":2.3978952727983707,"endowment":2.3978952727983707,"self_citation_contribution":0.3596842909197557,"citation_network_contribution":0.0,"self_endowment_contribution":0.3596842909197557,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":10,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.6087,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":409898,"name":"Fangyu Liu","orcid":"0000-0003-1554-1478","position":1,"is_corresponding":false},{"id":490122,"name":"Vadim Zipunnikov","orcid":"0000-0001-9864-2420","position":2,"is_corresponding":false},{"id":250664,"name":"Murat Bilgel","orcid":"0000-0001-5042-7422","position":3,"is_corresponding":false},{"id":373360,"name":"Jill A. Rabinowitz","orcid":"0000-0002-3674-8032","position":4,"is_corresponding":false},{"id":254759,"name":"Yang An","orcid":"0000-0002-3312-7265","position":5,"is_corresponding":false},{"id":428084,"name":"Junrui Di","orcid":"0000-0001-6325-8090","position":6,"is_corresponding":false},{"id":402037,"name":"Jiawei Bai","orcid":"0000-0003-4021-0101","position":7,"is_corresponding":false},{"id":503931,"name":"Sarah Wanigatunga","orcid":null,"position":8,"is_corresponding":false},{"id":272105,"name":"Mark N. Wu","orcid":"0000-0002-1329-0655","position":9,"is_corresponding":false},{"id":253620,"name":"Brendan P. Lucey","orcid":"0000-0001-5400-825X","position":10,"is_corresponding":false},{"id":264188,"name":"Jennifer A. Schrack","orcid":"0000-0001-9244-9267","position":11,"is_corresponding":false},{"id":409899,"name":"Amal A. Wanigatunga","orcid":"0000-0002-5763-5184","position":12,"is_corresponding":false},{"id":320072,"name":"Paul B. Rosenberg","orcid":"0000-0003-1106-4299","position":13,"is_corresponding":false},{"id":264194,"name":"Eleanor M. Simonsick","orcid":"0000-0002-5460-3494","position":14,"is_corresponding":false},{"id":34922,"name":"Keenan A. Walker","orcid":"0000-0002-5989-9853","position":15,"is_corresponding":false},{"id":21956,"name":"Luigi Ferrucci","orcid":"0000-0002-6273-1613","position":16,"is_corresponding":false},{"id":230044,"name":"Susan M. Resnick","orcid":"0000-0003-1115-7145","position":17,"is_corresponding":false},{"id":439252,"name":"Adam P. Spira","orcid":"0000-0003-1507-0995","position":0,"is_corresponding":true}],"reference_count":30,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T02:00:34.490087Z","pmid":"38381532","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}