Special Journal Issue Focuses on Delirium and Dementia in Older People

What: Studies indicate that each year more than 2.5 million hospitalized older adults experience delirium, a state of acute mental confusion. Delirium is worrisome to patients and to their families and friends, and it is estimated that complications associated with the condition cost Medicare $6.9 billion annually. A special section in the newest issue of the Journal of Gerontology: Medical Sciences focuses on possible causes of delirium, ways to better predict patients’ risk for delirium, potential approaches to prevention and treatment, possible long-term effects of delirium and its association with dementia.

Summary of articles: This special section, edited by Sharon K. Inouye, M.D., Harvard Medical School, and Luigi Ferrucci, M.D., National Institute on Aging (NIA), part of the National Institutes of Health (NIH), includes five articles on research supported by NIA and other public and private funders.

The researchers examined several areas that could help improve understanding of delirium, including biological and behavioral influences and the potential for biomarkers or imaging techniques to aid in identifying those at risk.

• Biomarkers for delirium – This review examines methods to study delirium by tracking chemical compounds in the blood that may be present at different stages of the condition. Such methods, the authors note, could be used to improve monitoring of delirium treatment and provide insights into the relationship between delirium and dementia.

• Imaging techniques – Two papers discuss the application of brain imaging techniques to further understand brain and behavior changes associated with delirium. In one study, researchers examined blood flow in the brain in a small number of delirious patients and found that roughly half of them had abnormalities in blood flow to certain parts of the brain. (NIH’s National Institute on Neurological Disorders and Stroke co-funded part of this research.)

• Post-anesthesia delirium – Some surgery patients, particularly older patients, experience delirium following anesthesia; however, the reason is unknown. Isoflurane, an inhaled anesthetic, can trigger changes in brain cells that are hallmarks of Alzheimer’s disease, including cell death and increased clumping of amyloid beta protein. In the present study, researchers exposed human brain tumor cells, engineered to produce amyloid beta protein, to isoflurane. This resulted in increased amyloid beta protein clumping and cell death. Introducing a compound that inhibits the clumping of amyloid beta protein kept the cells alive. The results suggest a possible common mechanism for behavioral problems in delirium and Alzheimer’s disease.

• Education – A secondary analysis of two hospital-based studies found that as years of education increase, risk for delirium decreases. The study authors suggest that education may be a factor in “cognitive reserve,” which may allow individuals to better cope with brain insult.

These papers report on research presented at a 2006 meeting sponsored by the NIA-funded Massachusetts Alzheimer’s Disease Research Center and Hebrew SeniorLife. The meeting was supported by a grant from the Alzheimer’s Association.

NIA Spokesperson: Reporters who would like to schedule an interview with Molly V. Wagster, Ph.D., chief of the NIA Neuropsychology of Aging Branch, may contact Megan Homer or Linda Joy in the NIA Office of Communications and Public Liaison at 301-496-1752 or nianews3@mail.nih.gov.

The NIA leads the federal effort supporting and conducting research on aging and the medical, social and behavioral issues of older people, including Alzheimer’s disease and age-related cognitive decline. For information on cognitive issues and aging, please visit the NIA’s Alzheimer’s Disease Education and Referral Center at www.nia.nih.gov/alzheimers, or call 1-800-438-4380. For more general information on research and aging, go to www.nia.nih.gov.

The National Institutes of Health – the nation’s medical research agency – includes 27 institutes and centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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