Differences in the Brains of Men and Women with Alzheimer's Disease
New research reveals how gender influences memory loss.
--by Alexia Severson
The pattern of gray matter volume loss in the brains of patients with Alzheimer’s disease is significantly different for men and women, according to a study presented at this year's annual meeting of the Radiological Society of North America.
Alzheimer’s disease (AD) is a form of dementia that gradually gets worse over time, affecting memory, thinking, and behavior. According to the Alzheimer's Association, it is the sixth leading cause of death in the U.S. and affects 5.4 million Americans.
While all patients with AD lose brain cells, this study reveals that the extent of cell loss may be greatly influenced by gender.
The Expert Take
In this study, researchers created brain maps based on magnetic resonance images (MRIs) of patients’ brains, revealing that compared to male patients, women had greater atrophy in gray matter 12 months prior to their AD diagnosis and at the time of their diagnosis. The brain maps also showed that men and women lost gray matter volume in different areas of the brain as their disease progressed from mild cognitive impairment (MCI) to AD.
"There is a strong interest in using magnetic resonance imaging to assess brain atrophy with the purpose of monitoring dementia progression noninvasively and to aid in understanding which factors can influence brain atrophy progression and distribution in the Alzheimer's brain," said lead researcher Maria Vittoria Spampinato, associate professor of radiology at the Medical University of South Carolina.
Spampinato and her colleagues also found other differences among men and women with AD. For example, while female patients in the study initially had more gray matter atrophy than male patients, the disease developed more aggressively over a shorter period of time in men.
"These differences should be taken into consideration when testing new drugs in clinical trials," Spampinato said. "Knowing the difference between the male and female patterns of atrophy will help researchers better decipher a patient's response to drug therapy."
Source and Method
Researchers analyzed data on 109 patients, including 60 men and 49 women with an average age of 77. All participants took part in the Alzheimer's Disease Neuroimaging Initiative, a major study that followed hundreds of cognitively healthy individuals and individuals with MCI and AD over a period of five years.
During the five-year period, each of the 109 patients progressed from amnestic MCI, in which the patient suffers memory loss but maintains cognitive function, to AD. The researchers created brain maps that illustrated gray matter changes using MRI images of the patients' brains taken when they were diagnosed with AD and 12 months before and after the diagnosis.
While this research may not lead to a cure for AD, it does offer a better understanding of the disease and the different ways in which it affects males and females. According to Spampinato, these gender differences also play an important role in developing therapies for MCI and AD.
A few other studies have examined the differences between men and women with AD. One study, published in the Journal of the American Geriatrics Society in 1996, examined the relationship between gender and specific types of behavioral problems that occur in patients with Alzheimer's. Researchers concluded that “although overall severity of behavior disturbance in Alzheimer's disease may be related primarily to severity in dementia, significant differences in the types of behaviors manifested exist between males and females with the disease.”
Another study, published in Neurology in 1995, looked at gender differences in language in AD patients and found that while both men and women decline at similar rates, the language abilities of women are more severely impaired overall.
More recently, a study published in Neurology in 1999 looked at the difference in risk for dementing diseases between men and women. Researchers in this study concluded that women have a higher risk of AD than men, but that no other gender differences in risk for vascular dementia exist.