Researchers studying postoperative delirium find that it’s important to assess patients for possible delirium before surgery, and that exhibiting a higher cognitive reserve can protect patients from delirium.

“We looked at cognitive reserve measures early in life — education and literacy — and we looked at late-life reserves, such as how many activities you do that are mentally stimulating,” says Joe Verghese, MBBS, MS, professor of neurology and medicine and chief of the Integrated Divisions of Cognitive & Motor Aging (Neurology) and Geriatrics (Medicine) at Albert Einstein College of Medicine in Bronx, NY. Verghese also is the director of the Montefiore Einstein Center for the Aging Brain.

Verghese and colleagues found that late-life cognitive reserve was associated with lower delirium incidence and severity in older surgery patients. Researchers theorized that interventions to enhance cognitive reserve by initiating or increasing participation in cognitive activities could be a delirium prophylaxis strategy.1

Cognitive Deficits, Dementia Risk

Delirium is a confused mental state associated with altered consciousness and decreased attention. It can affect 20-60% of surgical patients, depending on the type of surgery. It also manifests in two forms: the hypoactive form, in which the patient is quiet, or the hyperactive form, in which patients are agitated physically and pose a potential harm to themselves and others, Verghese says.

“It’s common in older patients admitted to the hospital for surgery or acute infections,” he says.

Patients who experience delirium are more likely to demonstrate cognitive deficits and to develop dementia, and their surgical outcomes often are not as good as patients who do not experience dementia, Verghese adds.

All these factors make it important for surgeons, from a risk assessment perspective, to identify patients’ potential for dementia. One way is to look at a person’s cognitive reserve, indicated by his or her intellectual activities, he suggests.

“Overall, older adults who reported reading books and doing computer games were less likely to have delirium after surgery, and if they had delirium, it was less severe,” Verghese says.

Using email and singing also were associated with lower dementia incidence and severity.1

Delirium in post-surgery patients typically picks up a day or two after surgery. Earlier confusion likely is related to pain medications, he explains.

“If you are assessing someone for elective surgery and you find out they have low education and are not mentally stimulated, then you could find that the person is at high risk of delirium and monitor them more closely,” Verghese says.

Another new study found that when nurses used delirium-friendly preprinted postoperative orders with hip fracture patients, the intervention patients were less likely to develop delirium than those in a control group.2

Surgery centers might track delirium through follow-up visits.

“Most cases of delirium occur the first week after surgery,” Verghese says. “In this study, we looked at the day after surgery and repeated an exam of the patient a day or two after that to make sure they didn’t have delayed onset of delirium.”

The surgeries studied were elective, in which patients would be in a hospital setting for two to three days after surgery.

“Elective surgeries are becoming increasingly common as more people require hip and knee surgery,” Verghese says. “There’s a push to get patients out of hospitals sooner after surgery, partly for economic reasons, and you don’t want people in hospitals too long because they can pick up infections.”

Delirium typically comes in two forms, either an agitated or quiet form, Verghese says.

“The agitated patients are easier to identify because they are active,” he explains. “The others are not moving around, but they’re confused.”

Outcomes are the same for either type of delirium, he notes.

Researchers are beginning to imagine the possibility of developing a program of cognitive stimulation that might reduce the risk and severity of delirium. “There usually is a gap between initial assessment and surgery, and it’s possible to do a brain-building program to build up a person’s reserve,” Verghese says.

“We want to apply for a grant to see if this would work,” he says. “We want to show that someone with a low level of mentally stimulating activities would benefit from an intense period of brain game program.”

The theory is that these brain-stimulating activities would reduce delirium and could be incorporated into routine preoperative procedures, Verghese explains.

There especially is interest in researchers developing a way to test cognitive reserve for the purpose of preventing delirium, but that also requires more study, he says.


  1. Tow A, Holtzer R, Wang C, et al. Cognitive reserve and postoperative delirium in older adults. J Am Geriatr Soc 2016:64:1341-1346.
  2. Freter S, Koller K, Dunbar M, et al. Translating delirium prevention strategies for elderly adults with hip fracture into routine clinical care: A pragmatic clinical trial. J Am Geriatr Soc 2016. Epub ahead of print.