Enhancing 'Brain Reserve' Might Delay Onset of Alzheimer's

Dementia is a brain disorder that seriously affects a person's ability to carry out daily activities, and Alzheimer's disease (AD) is the most common form of dementia among older people.

Anyone can develop Alzheimer's disease, but people who have a family history of the disease are at a four times higher risk of getting it themselves, says Piero G. Antuono, MD, Medical College of Wisconsin Professor of Neurology and Director of the Memory Disorders Program at Froedtert & the Medical College of Wisconsin.

"If you look at your parents, you can look at your future and health conditions," he notes.

A Gradual Loss
Alzheimer's disease disrupts nerve cells in the brain, causing them to stop working, lose connections with other nerve cells, and die. Insoluble protein deposits called plaques form in some areas of the brain, and twisted fibers called neurofibrillary tangles develop inside the nerve cells.

These changes cause the symptoms that we associate with AD - memory failure, personality changes, problems in carrying out daily activities, and other features of the disease.

The symptoms of AD begin slowly. The initial changes involve the parts of the brain that control thought, memory and language. People with AD might have trouble remembering things that happened recently or names of people they know. Over time, symptoms get worse. People may not recognize family members or have trouble speaking, reading or writing. They may forget how to brush their teeth or comb their hair. Later on, they may become anxious or aggressive, or wander away from home. Eventually, they need total care. This can cause great stress for family members who must care for them.

The disease begins long before its symptoms are obvious. "When we make a diagnosis today, the disease has been going on for probably 10 to 20 years," says Dr. Antuono, but the brain continues to function fairly well because humans possess a great deal of "brain reserve" - the ability to maintain good cognitive function even as disease breaks down delicate tissues and vessels.

"There is evidence that if we treat things that reduce your brain reserve, that is if we can protect your brain, it may take the disease 25, maybe 30 years to show," Dr. Antuono says. "The prevailing mantra is what's good for the heart is good for the brain. If you do physical exercise, you actually improve your cognitive performance. Because you have more oxygen, you have better circulation. Exercise also helps prevent and treat problems such as anxiety and depression, he adds.

You can enhance your brain health by "keeping your blood pressure low, keeping your cholesterol low and avoiding head trauma. (Head trauma can increase the risk of Alzheimer's disease three-fold.) Hypertension in middle age is a very important risk factor for dementia," Dr. Antuono advises.

Focus on Early Identification, Prevention
Dr. Antuono cites research that is giving new direction to efforts at understanding the disease process. "They've done studies showing that people who have higher educations are protected from getting Alzheimer's. Education, per se, might not train the brain and create brain reserve, but it may be a marker of people who have bigger brains or better-connected, more efficient brains," he notes.

"We were involved in "The Nun Study", which looked at retired Catholic nuns. The nuns who were the leaders, the international leaders, the PhDs and so forth were the ones who had much less Alzheimer's than the sisters who were the seamstresses, the bakers, the housekeepers. It's a definite connection to education."

In the study, the sisters who had more than seven siblings were also at a higher risk for Alzheimer's disease. "Generally in very large families there are fewer resources as you're growing up, as the brain is developing," Dr. Antuono said. The availability of protein, prenatal care and medical attention may affect the risk for children in large families, as the brain has usually completed most of its growth by age six.

Dr. Antuono believes that identifying people at future risk for the development of Alzheimer's disease gives us a window of opportunity to intervene.

"We're doing studies in children of Alzheimer's patients because we know that they're at high risk," he said. The program is trying to find markers with fMRI (functional MRI) so if a treatment is developed, those who need to be targeted will already be identified.

"Studies are being conducted also on those in the early stages of the disease as well as with MCI, or mild cognitive impairment. The Memory Disorders Program is working to identify those most at risk for early diagnosis and possible intervention."

Melissa Rigney Baxter
HealthLink Contributing Writer

Piero G. Antuono, MD, practices at the Neuroscience Center at Froedtert & Medical College Clinics.

This article includes information from the National Institute on Aging.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.