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The Delirium Connection

The Delirium Connection
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Winter 2023
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A complex condition that can happen after surgery may be linked to dementia

Poor memory. Disorientation. Personality changes. When waking from surgery, patients may experience these alarming symptoms, eliciting concern from their family members and doctors. Often these symptoms are the result of delirium — a condition that can be caused by a variety of factors such as surgery, certain medications, alcohol or drug withdrawal, or medical conditions. While delirium typically lasts less than one to three days, in some cases it can persist for months and lead to long-lasting complications — even death.

Given the similarities in symptoms, delirium can be mistaken for dementia. There are key differences — dementia develops more slowly, progresses steadily and is typically caused by neurodegenerative diseases like Alzheimer's. Although the two are different conditions, researchers are uncovering growing evidence that people who experience delirium may be at higher risk for dementia.

Scientists don't yet understand the connection, says Lisbeth Evered, Ph.D., M.Sc., associate professor of Neuroscience in Anesthesiology at Weill Cornell Medicine in New York and associate professor of Critical Care at the University of Melbourne in Australia.

"In community studies, we know that an episode of delirium is associated with an increased risk of progression to dementia," says Evered. However, she notes that it's unclear whether delirium that occurs after surgery actually heightens dementia risk or simply reveals previously undiagnosed neurodegenerative disease in some people.

Delirium is a common and serious problem among hospitalized older adults, including those who have surgery. While delirium can happen to anyone, risk increases with age, and people already living with dementia are especially vulnerable to episodes, which can accelerate decline. There are many factors that can increase risk, explains Sharon K. Inouye, M.D., MPH, professor of medicine at Harvard Medical School and director of the Aging Brain Center, Marcus Institute for Aging Research at Hebrew SeniorLife.

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"Persons with underlying brain vulnerability are most likely to develop delirium with any stressors," says Inouye, noting that these stressors can include the person's health condition, the major surgery itself or other medical factors like new medications, sleep deprivation and immobilization. The anxiety and stress of being in the hospital also has an impact. "It's this combination of multiple adverse factors that culminates in delirium," she says.

Inouye's trailblazing work has helped doctors not only diagnose delirium but also prevent it. After creating the Confusion Assessment Method (CAM), which helps health care professionals screen patients for delirium, she developed the innovative Hospital Elder Life Program (HELP) — which has been shown to prevent delirium in about 50% of cases.

HELP uses a variety of proven nondrug approaches, such as cognitive orientation, therapeutic activities and sleep enhancement strategies, to counteract the stressors older adults commonly experience in the hospital. For instance, updating a whiteboard in a patient's room after surgery with the date, schedule and names of doctors and nurses can help prevent confusion.

The program is tailored to the individual and provides enjoyable activities based on their interests (like reading or trivia games) that will help them stay engaged with other people and their environment during their hospital stay.

Inouye was inspired by the Child Life program used in many hospitals, which she experienced as a parent when her own kids were growing up. "I was so impressed with the humanistic care that was provided, the bedside attention. As a geriatrician, I was like, 'Why aren't we doing this for older adults?' So, that was the genesis."

To date, the HELP program has been established at more than 200 hospitals worldwide.

One day, Evered hopes to see widespread implementation of delirium screening well before surgery to help doctors spot people who are most vulnerable. In the meantime, she wants individuals and families to know that there are preventive steps they can take together with their care team, such as healthy eating and exercise, to better prepare the body and mind for surgery. She also recommends people learn about their risk factors in advance.

"If you have any concerns about even subtle cognitive impairment, your primary care physician can do a very short assessment," she says. "And patients should understand all of the [potential benefits and risks] when they're making a decision about going ahead with surgery. It's too late once they're admitted to the hospital and the wheels are in motion."

Ways to Reduce Risk of Delirium After Surgery

If you have any concerns about memory or thinking problems, talk to your doctor before your operation.

To the best of your ability and under the guidance of your doctor, maintain a healthy diet and exercise regimen.

Review your existing medications with your care team to avoid potential interactions.

If possible, seek out a hospital that offers interventions to help prevent delirium, like HELP or a similar program, and request these services. To learn more about HELP, visit

To learn more about delirium and how to prevent it, visit (a website maintained by Dr. Sharon K. Inouye and the Aging Brain Center team at the Marcus Institute for Aging Research, a Harvard Medical School affiliate).


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