Courtesy of GE Healthcare
RSNA 2012: Women vs. men, golf and Alzheimer's
November 27, 2012
by Brendon Nafziger
, DOTmed News Associate Editor
RSNA 2012: Women vs. men, golf and Alzheimer's
Women's brains shrink sooner than men's in early Alzheimer's as measured by MRI scans and a plethora of activities from golf to gardening are linked with less brain volume loss in the elderly, according to a pair of studies presented Monday at the Radiological Society of North America's annual meeting in Chicago.
The researchers said the preliminary findings could help in the understanding and care of patients afflicted with the degenerative disease, which affects some 5 million Americans each year.
In the first study, using a subset of 109 patients from the larger Alzheimer's Disease Neuroimaging Initiative, MRI scans reveal women lose more brain volume than men in the early stages of Alzheimer's disease. However, the difference vanishes about a year after diagnosis.
Also, although women have greater volume loss initially, it's not linked to worse cognitive function, suggesting females might have a "greater cognitive reserve," according to lead author Dr. Maria Spampinato, a radiology professor at the Medical University of South Carolina in Charleston.
For the study, Spampinato and colleagues collected MRI scans on 60 men and 49 women suffering from amnestic mild cognitive impairment (aMCI), in which they have memory loss but are otherwise cognitively normal, who went on to develop full-blown Alzheimer's. (Usually, about one-tenth of aMCI patients will go on to develop Alzheimer's, Spampinato said.)
The researchers then examined gray matter volume in MRI scans taken one year before their Alzheimer's diagnosis, at the time of diagnosis, and then one year following the diagnosis. Spampinato said women had more atrophy than men in the 12 months preceding their diagnosis and at the time of their diagnosis. However, in the one-year follow-up scan men had caught up with the women.
Looking specifically at the volume of the hippocampus, a brain structure associated with memory and implicated in Alzheimer's, men had larger volumes initially but experienced a steeper drop in volume after their disease progressed, Spampinato said.
"Male and female brains respond differently to Alzheimer's disease pathology," Spampinato told reporters at a press conference Monday announcing the findings.
Why does the disease affect men and women differently? Spampinato said there's no "single unifying" cause but researchers suspect it could be a mixture of hormonal and genetic risk factors. "Hormones definitely play a role," she said.
Interestingly, Alzheimer's gender differences have been discovered before. Spampinato said it's known that women have one and a half times greater risk of developing the disease, and they're believed to be more impaired in language and memory when the disease first presents itself. Women also are more prone to depression, and men to aggression, over the course of the affliction, she said.
Golf to gardening
But for men and women at risk for Alzheimer's, or who have the disease, researchers at RSNA also found some potentially heartening news: a variety of physical activities were linked with less brain volume loss, also measured using an MRI technique, in both healthy older adults and those with cognitive impairment.
This could have important implications for seniors, as the study suggests any number of aerobic activities from dancing to swimming to racquetball, might be beneficial.
"Individuals who are elderly need to be able to customize" their exercise regimens, said study author Dr. Cyrus Raji, a radiology resident at UCLA.
In his study, Raji used a technique called voxel-based morphometry to quantify gray matter. The study, which used a GE Healthcare-made 1.5-Tesla MRI scanner, was "one of the largest voxel-based imaging studies on humans ever done," he said, involving some some 876 MRI scans taken at four sites around the country, as part of a larger cardiovascular health trial.
Raji said they gave patients a survey, the Minnesota Leisure-Time Physical Activity Questionnaire, asking what physical activities they did in the previous two weeks. The researchers then estimated the amount of calories burned during the self-reported activities, and then compared brain scans of patients with their activity levels.
After controlling for a number of factors, such as age, gender, body-mass index, head size and dementia status, the researchers said they found the most active patients had 5 percent more gray matter, as measured by the scans, than the least active patients. The most active patients, who burned 3,434 kilocalories a week, had around 664 mL of gray matter, compared with the least active, who burned about 348 kilocaries a week, and had 628 mL of gray matter, he said.
Although the study doesn't show exercise caused a slowdown in gray matter loss among the most active patients, Raji said an earlier study in which patients were randomly assigned to a walking group had 2 percent greater gray matter volume in part of their brain than control patients.
Why would physical activities help? Raji said it's believed aerobic exercise can help boost blood flow to the brain and increase neurotrophic growth factors.