Delirium is an acute decline in attention and cognition.  It is a common, life-threatening, and potentially preventable clinical syndrome among persons who are 65 years of age or older.  The development of delirium often initiates a cascade of events culminating in the loss of independence, an increased risk of morbidity and mortality, and increased health care costs.  Delirium in hospitalized older patients has assumed particular importance because the care of such patients accounts for more than 49 percent of all hospital days, complicates hospitals stays for at least 20 percent of the 12.5 million patients 65 years of age or older who are hospitalized each year and increases hospital costs by $2,500 per patient.  Substantial additional costs accrue after hospital discharge because of the need for institutionalization, rehabilitation services, formal home health care, and informal caregiving.  Delirium is often unrecognized by the patients' physicians and nurses, in part because of its fluctuating nature, its overlap with dementia, lack of format cognitive assessment, underappreciation of its clinical consequences, and failure to consider the diagnosis important.  (Source: Inouye SK.  Current concepts:  Delirium in older persons.  N Engl J Med. 2006; 354:1157-1165.)

Depressive symptoms are common in elderly hospitalized patients, with significant symptom levels occurring in 10 to 44% of patients.  The presence of depressive symptoms during hospitalization is associated with adverse outcomes.  It is now recognized that among elderly patients hospitalized with a range of medical diagnoses, those with depressive symptoms are at increased risk of poor post-hospitalization outcomes including worse physical and mental health, functional decline and increased mortality.  The presence of an overlap syndrome of depression and delirium in hospitalized patients has not been well studied, although depressive symptoms are an established risk factor for the development of delirium.  Due to the high prevalence of depressive symptoms and delirium among elderly hospitalized patients and their association with poor post-hospitalization outcomes, the question of whether patients with an overlap of these two conditions are at even greater risk of adverse outcomes has clinical importance but has not been investigated previously.  Members of the Aging Brain Center Working Group recently completed a study with Dr. Jane Givens of the Institute for Aging Research, with the goal of closing gaps in current knowledge regarding the coexistence of depression and delirium.  (Source: Givens JL, Jones RN, Inouye SK.  The Overlap Syndrome of Depression and Delirium in Older Hospitalized Patients.  Submitted.)

The Hospital Elder Life Program (HELP) was the developed by Sharon K. Inouye, M.D., M.P.H., currently the director of the Aging Brain Center, at Yale University School of Medicine.  Tested in the Yale Delirium Prevention Trial, it is an innovative approach to improving the hospital care for older patients.  Kerry Fenlon, MSW, MBA, has recently joined the staff of the Aging Brain Center as the Associate Director of HELP Dissemination.  Please visit http://elderlife.med.yale.edu to learn more about HELP. 

Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain.

Neuropathology is the study of disease of nervous system tissue, usually in the form of either small surgical biopsies or whole autopsy brains.

Pathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome. More formally, it is the branch of medicine which deals with any disturbances of body functions, caused by disease or prodromal symptoms.

"Reserve" refers to passive and active processes in the brain that modify an individual's risk for expression of clinical signs and symptoms associated with brain injury or neuropathology.  The concept of reserve has been cited as a theoretical framework for explaining individual differences in risk for, and patterns of, cognitive impairment associated with dementia, brain injury or medical illness.  Reserve has been suggested to account for individual differences in risk for delirium; however, there is a dearth of research examining this.  An active model of reserve, cognitive reserve, refers to the degree of efficiency with which an individual uses relevant brain networks or cognitive strategies to cope with brain injury.  Emerging evidence suggests reserve may be a potentially modifiable characteristic.  Studying the role of reserve in delirium can advance prevention strategies for delirium and may advance knowledge of reserve and its role in aging and disease more generally.  (Sources: Jones RN, Yang FM, Zhang Y, Kiely DK, Marcantonio ER, Inouye SK.  Does educational attainment contribute to risk for delirium? A potential role for cognitive reserve.  J Gerontol Med Sci. 2006;61A:1307-1311; Jones RN, Fong TG, Metzger E, Tulebaev S, Yang FM, Alsop DC, Marcantonio ER, Cupples LA, Gottlieb G, Inouye SK.  Aging, Brain Disease, and Reserve: Implications for Delirium.  Submitted.)