BACKGROUND: Older adults frequently experience acute and long-term cognitive impairment following critical illness hospitalization in an intensive care unit (ICU). Delirium affects up to 80% of ICU patients and is linked to cognitive dysfunction and increased risk of cognitive decline associated with Alzheimer's disease and related dementias (ADRD). Sleep and circadian rhythm disturbances are present in about 75-80% of ICU patients and may exacerbate delirium and undermine cognitive interventions. Nonpharmacological interventions such as earplugs, eye masks, and computerized cognitive training show promise in reducing delirium and improving sleep but have not been rigorously tested - separately or combined - in older adult ICU survivors. Moreover, prior studies have not leveraged chronotherapeutic timing to align cognitive training with individual circadian rhythms.
OBJECTIVES: We propose a multi-modal combination of sleep promotion intervention [SLEEP], and computerized cognitive training program timed daily according to individual chronotype [COG], to improve cognitive function in hospitalized older adult ICU survivors. The primary aim is to test the feasibility, acceptability, and preliminary separate and combined effects of SLEEP and COG [SLEEP, COG, SLEEP+COG] versus an active control condition [AC] in improving cognitive function after the intervention period. The secondary aims are to explore: (1) circadian rhythm parameters of continuous body temperature to determine the optimal window for chronotherapeutic timing of cognitive interventions; (2) if the effects of each intervention on cognitive function are mediated by sleep and activity; (3) if biopsychosocial and clinical factors moderate the effects of each intervention on cognitive function; and (4) the effects of each intervention on cognitive function at 1, 6, and 12 months.
METHODS: After discharge from ICU, English- or Spanish-speaking older adult ICU survivors ( n =100) are randomly assigned to 7 days of (1) SLEEP, (2) COG, (3) SLEEP+COG, or (4) AC. Cognitive function, delirium severity, sleep and circadian rhythms, patient-reported symptoms, and data regarding biopsychosocial and clinical factors are collected.
RESULTS: Results are pending study completion.
DISCUSSION: We aim to target sleep and circadian rhythm disturbances, mitigate ICU delirium, and reduce cognitive decline associated with ADRD. If hypotheses are supported, this combination of low-cost, non-pharmacological interventions could be integrated into standard care to accelerate cognitive recovery during hospitalization.
