Alzheimer's: A Disease of the Brain

by Food and Drug Administration (FDA)

It was 1997 when an alarm went off in Vivian Freed's head. She knew something was wrong with her 85-year old mother, who had always planned her trip to celebrate Thanksgiving with her children down to the last detail. But that year, she got the airline tickets for the wrong days. Freed also found out that her mother had been missing doctors' appointments and social engagements, so she flew from her home in Rockville, Md., to her mother's home in Florida to check on her.

"Everything that she had done perfectly before was a mess," says Freed. The bills weren't paid, and the medications that her mother had been giving to her ailing father weren't right. "We realized we needed to do something," says Freed, after a doctor diagnosed her mother with Alzheimer's disease.

Freed's sister, Annette Heller, later "adult-napped" her parents and moved them to Maryland under the pretense of just visiting." They didn't really notice that she was packing up more things than they would need for just a visit," says Freed.

Her parents were fiercely independent and would have objected to moving. "It would have been much nicer to give them closure, but it wasn't possible," Freed says.

Not long after Freed moved her parents into an assisted living facility in Maryland, her father passed away. "The day after he died, Mom remembered what happened, but never did again," she says. "Mom kept asking, 'Where's Daddy?'"

As her mother's mental and physical health continued to deteriorate, Freed moved her into a small group home where she got 24-hour care. Alzheimer's disease, along with worsening vision, prevented her mother from recognizing Freed. "It was a very slow demise," she says. Her mother died at age 90 in 2002.

"Ultimately, Alzheimer's is fatal," says William Thies, Ph.D., vice president of medical and scientific affairs at the Alzheimer's Association in Chicago. "Until research provides the answers, Alzheimer's will continue to exact a terrible toll on those with the disease, as well as on their families, friends and caregivers."

But an explosion of Alzheimer's research in the last 10 years and its continuing momentum hold out hope for potential preventions and treatments for this devastating disease.

Rising Numbers

Health care costs for the roughly 4.5 million Americans with Alzheimer's disease (AD) exceed $100 billion a year, according to the Alzheimer's Association. As baby boomers age during the next few decades, the number of victims and the dollar costs of care are expected to almost quadruple.

As age increases, so does the risk of getting AD. For each five-year age group beyond 65, the percentage of people with AD doubles, according to the National Institute on Aging (NIA). Nearly half of those over age 85 have it. A small number are diagnosed with "early-onset Alzheimer's," which can strike people in their 30s, but most AD cases are among older people. A person with AD lives an average of eight years after the onset of symptoms, but some live as long as 20 years.

A Disease of the Brain

AD is a brain disorder that occurs gradually. It starts with mild memory loss, changes in personality and behavior, and a decline in thinking abilities (cognition). It progresses to loss of speech and movement, then total incapacitation and eventually death. It is normal for memory to decline and the ability to absorb complex information to slow as people get older, but AD is not a part of normal aging.

Researchers aren't exactly sure what causes AD, but they do know that people with the disease have an abundance of two abnormal structures in the brain: plaques and tangles. Plaques are dense, sticky substances made up of accumulations of a protein called beta-amyloid. Tangles are twisted fibers caused by changes in a protein called tau. The beta-amyloid plaques reside in the spaces between the billions of nerve cells, or neurons, in the brain, and the neurofibrillary tangles clump together inside the neurons. Plaques and tangles block the normal transport of the electrical messages between the neurons that enable us to think, remember, talk and move. As AD progresses, nerve cells die, the brain shrinks, and the ability to function deteriorates.

Healthy nerve cells in the brain (neurons) have support structures called microtubules, which guide nutrients and molecules from the cell's body down to the ends and back. A special kind of protein, tau, makes the microtubules stable. Tau is changed chemically in people with Alzheimer's disease. It begins to pair with other threads of tau and they become tangled up together. When this happens, the microtubules disintegrate, collapsing the neuron's transport system. This may result first in communication malfunctions between neurons and later in cell death.

About the Author

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