The American Geriatrics Society/National Institute on Aging Bedside-to-Bench Conference: Research Agenda on Delirium in Older Adults

Abstract

The American Geriatrics Society, with support from the National Institute on Aging and the John A. Hartford Foundation, held its seventh Bedside-to-Bench research conference, entitled “Delirium in Older Adults: Finding Order in the Disorder” on February 9–11, 2014, to provide participants with opportunities to learn about cutting-edge research developments, draft recommendations for future research involving translational efforts, and opportunities to network with colleagues and leaders in the field. This meeting was the first of three conferences that will address delirium, sleep disorders, and voiding difficulties and urinary incontinence, emphasizing, whenever possible, the relationships and potentially shared clinical and pathophysiological features between these common geriatric syndromes.

Keywords: Geriatric syndromes; cognition; delirium; interventions; measurement; pathophysiology.

Figure 1

Potential common mechanisms and risk factors for 7 three common geriatric syndromes—delirium, sleep disorders, and voiding dysfunction—which are the topics for the current American Geriatrics Society/National Institute on Aging Bed-side-to-Bench Conference Series. All three syndromes have common predisposing factors, including physical frailty and cognitive impairment, and can be precipitated by acute stressors, which include medications and acute illnesses.

Figure 2

Delirium risk increases with aging: the relevance of homeostenosis (progressive constriction of homeostatic reserve with aging) to delirium. A young person is subjected to a stressor that perturbs function out of normal range but within the limits of compensatory reserve; in this case, compensatory mechanisms are recruited, and the individual returns to homeostatic equilibrium. An older person subjected to the same stressor (orange arrow of similar length) is now beyond the reserve limits because of aging-related homeostenosis. In this case, compensatory mechanisms are overwhelmed, and decompensation occurs, which, if brain-centered, results in delirium. This model also suggests two broad types of interventional approaches to reduce risk of delirium: reducing stressors and increasing homeostatic reserve. Both approaches are discussed further in the text.