Radiologists identify early brain marker of Alzheimer's disease

Sep 25, 2007

Researchers using functional magnetic resonance imaging (fMRI) have found a new marker which may aid in early diagnosis of Alzheimer’s disease, according to a study published in the October issue of Radiology.

“The findings of this study implicate a potential functional, rather than structural, brain marker—separate from atrophy—that may help enhance diagnosis and treatment monitoring of Alzheimer’s patients,” said the study’s lead author, Jeffrey R. Petrella, M.D., associate professor of radiology at Duke University Medical Center in Durham, N.C.

Alzheimer’s disease is a progressive brain disorder characterized by memory loss, confusion, personality or behavioral changes and other symptoms. According to the Alzheimer’s Association, more than five million Americans currently have Alzheimer’s disease.

While there is still no cure for the disorder, early diagnosis is crucial so that the patient receives proper treatment.

“As new therapies for Alzheimer’s disease enter the pipeline over the next five years, early diagnosis will become critical for patient selection,” Dr. Petrella said. “fMRI may play a key role in early diagnosis, when combined with clinical, genetic and other imaging markers.”

Among the earliest known changes to the brain in Alzheimer’s disease are episodic memory deficits and structural changes in the medial temporal lobe (MTL). For the study, Dr. Petrella and colleagues set out to identify brain regions in which changes in activation took place during a memory task and to correlate these changes with the degree of memory impairment present in patients with Alzheimer’s disease or mild cognitive impairment.

The researchers studied 13 patients with mild Alzheimer’s disease, 34 patients with mild cognitive impairment and 28 healthy controls. The study group contained 37 men and 38 women with a mean age of 72.9 years. After completing standard neuropsychological testing, the study participants were monitored with fMRI while performing a face-name associative memory task.

While some areas of the brain activate, or turn on their activity, when a person tries to remember something, other areas deactivate, or suppress their activity. Results from this study showed that along the spectrum from healthy people at low risk, to people with mild memory problems, to patients with Alzheimer’s disease, there was increasingly impaired activation in the MTL, an area of the brain associated with episodic memory that normally turns on during a memory task. More surprising, however, was increasingly impaired deactivation in the posteromedial cortices (PMC), an area recently implicated with personal memory that normally suppresses its activity during a memory task. The magnitude of deactivation in the PMC was closely related to the level of memory impairment in the patients and significantly correlated with their neuropsychological testing scores.

While previous studies have suggested that MTL activation may be a possible marker of Alzheimer’s, based on the findings, Dr. Petrella and colleagues concluded that, compared to activation in the MTL, deactivation in the PMC may represent a more sensitive marker of early Alzheimer’s disease.

“In other words, the brain not only loses its ability to turn on in certain regions, but also loses its ability to turn off in other regions, and the latter may be a more sensitive marker. These findings give us insight into how the brain’s memory networks break down, remodel and finally fail as memory impairment ensues,” Dr. Petrella said.

The researchers hope that fMRI will eventually help to identify patients at risk for developing Alzheimer’s disease.

The next step is to conduct a large, multicenter study to see if fMRI can be combined with other imaging and genetic tests to scan for future disease,” said study co-author P. Murali Doraiswamy, M.D., chief of the Division of Biological Psychiatry and Alzheimer’s clinical trial expert at Duke. “Much like a negative colonoscopy gives you reassurance, a normal fMRI may, in the future, also offer predictive value.”

Source: Radiological Society of North America

Explore further: Lebanon reports first suspected case of Ebola

add to favorites email to friend print save as pdf

Related Stories

Frenchman Tirole wins Nobel economics prize

Oct 13, 2014

(AP)—French economist Jean Tirole won the Nobel prize for economics Monday for research on market regulation that has helped policymakers understand how to deal with industries dominated by a few companies.

The 2014 Nobel Prizes at a glance

Oct 13, 2014

(AP)—All winners of the 2014 Nobel Prizes have now been announced, starting with the medicine award a week ago and ending with the economics prize on Monday.

Modiano wins Nobel for works about Nazi occupation

Oct 09, 2014

Patrick Modiano of France, who has made a lifelong study of the Nazi occupation and its effects on his country, won the 2014 Nobel Prize in literature Thursday for what one academic called "crystal clear ...

The truth about the war on wheat

Oct 03, 2014

If you believe the best-seller lists, the biggest bad in the supermarket aisles is not fat or sodium or sugar, but wheat. We have been warned that eating wheat makes our bellies fatter and triggers diseases ...

Recommended for you

Lebanon reports first suspected case of Ebola

5 minutes ago

A Lebanese man who arrived from West Africa is suspected of having Ebola and was quarantined on Thursday in a Beirut hospital, the first such suspected case in the country, Lebanon's health minister said.

New, faster therapeutic hypothermia techniques

20 minutes ago

Rapid lowering of body temperature following an acute myocardial infarction (MI) can be an effective therapeutic strategy to minimize damage to the heart muscle caused by the loss and restoration of blood ...

Sri Lanka celebrates two years without malaria

4 hours ago

Sri Lanka has not reported a local case of malaria since October 2012, according to the Sri Lankan Anti-Malarial Campaign. If it can remain malaria-free for one more year, the country will be eligible to apply to the World ...

User comments : 0