Sundown Syndrome in Older Persons: A Scoping Review

Abstract

Objectives: To map comprehensive investigations of the sundown syndrome (SS), highlighting its key definition and associated characteristics.

Design: Scoping review of published articles on SS in PubMed, OVID, EMBASE, Scopus, CINAHL, and Science Direct.

Setting: Post-acute and long-term health care settings.

Participants: Older adults aged ≥60 years.

Measures: Articles must present primary data on specific SS behavior, with explicit psychopathological and quantitative outcomes; and/or evening disruptive behavior.

Results: From a total number of 460 articles focusing on psychopathology and standardized outcomes of SS, 23 were retained for the final analysis (n = 1210 subjects). The mean age of participants was 63.2 years, and slightly more participants were women. The samples were recruited by convenience from long-term care facilities and tertiary outpatient clinics. The frequency of SS varied from 2% to 82%, without evident difference between genders and race/ethnicity. Generally, the sundown episode occurred during later daytime, when psychomotor alterations and cognitive disturbance manifested repeatedly. The symptomatic manifestations of SS were heterogeneous across the studies. Demographic risk factors were inconsistent. Although some authors have viewed cognitive impairment as a substantive predisposing factor to SS, others supported SS as a predictor of looming cognitive decline. The disrupted circadian rhythm was the most accepted pathophysiology. To date, clinical trials to guide the management of SS with specific pharmacologic and nonpharmacologic approaches are scant.

Conclusions and implications: SS can be viewed as a cyclic delirium-like condition affecting the older population around the sunset hour that may last for a few hours. The scarcity of comprehensive studies makes it difficult to determine whether and to what extent it can represent a distinct disease, a prodromal stage of dementia, or an epiphenomenon of incipient or worsening dementia. Extensive gathering of clinical data from multiple health care settings, using uniform measurement tools, is much needed.

Keywords: Sundown syndrome; circadian rhythm; cognitive impairment; dementia; disruptive behaviors.