Delirium hastens memory decline in Alzheimer’s patients

May 5th, 2009 - 2:56 pm ICT by ANI  

Washington, May 5 (ANI): An episode of delirium rapidly accelerates cognitive decline and memory loss in Alzheimer’s patients, according to a study by researchers at Beth Israel Deaconess Medical Center (BIDMC) and Hebrew Senior Life.

Elderly patients often develop delirium during hospitalisation or serious illness, and this acute state of confusion and agitation has for long been suspected to be linked to Alzheimer’s disease and other dementias.

Alzheimer’s disease is an irreversible, progress form of dementia that gradually destroys a person’s ability to carry out even the simplest of tasks,

Delirium, on the other hand, is a potentially preventable condition that often develops following a medical disturbance, surgery or infection, and is estimated to affect between 14 percent and 56 percent of all hospitalized elderly patients.

“The cognitive rate of decline was found to be three times more rapid among those Alzheimer’s patients who had had an episode of delirium than among those who did not have such a setback,” according to lead author Dr. Tamara Fong.

Fong added: “In other words, the amount of decline you might expect to see in an Alzheimer’s patient over the course of 18 months would be accelerated to 12 months following an episode of delirium.”

The researchers conducted a secondary analysis of data gathered from 408 patients, examined between 1991 and 2006 at the Massachusetts Alzheimer’s Disease Research Center (MADRC).

Over this 15-year period, MADRC staff conducted a number of memory tests on patients, which was done on at least three occasions, separated by intervals of approximately six months.

They observed that 72 participants developed delirium during the course of the study.

In the final analysis, the researchers found that among patients who developed delirium, the average decline on cognitive tests was 2.5 points per year at the beginning of the study.

After an episode of delirium, decline nearly doubled to 4.9 points per year.

Fong said: “Although each dementia patient declines at his or her own individual rate, the results of our study tell us that this rate can increase three-fold following an episode of delirium.

“Older patients may be at greater risk of developing delirium - particularly in the hospital setting - because they tend to have less ‘reserve’ or ability to compensate in settings of increased stress. Consequently, infections, new medications and other stressors put the patient at risk for delirium.”

Fong further said that all elderly patients, but particularly patients who have already been diagnosed with Alzheimer’s disease, could benefit from a number of preventive measures if they are hospitalized.

“Our current study now shows that delirium can also adversely impact the state of cognitive decline in patients with Alzheimer’s disease. Because up to 40 percent of delirium episodes can be prevented, taking steps to avoid delirium could result in significant improvements,” said Fong.

The findings have been reported in the latest issue of the journal Neurology. (ANI)

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