

What is early onset Alzheimer's disease?

Liz Szabo
Tennessee head coach Pat Summit, left, hugs player Shekinna Stricklen after defeating Rutgersin 2009.

About 200,000 Americans suffer from early onset Alzheimer's disease, the condition that took the life Tuesday of legendary basketball coach Pat Summitt at age 64. She was diagnosed with the illness five years ago.

USA TODAY's Liz Szabo asked experts to explain the disease.

Q. How does early onset Alzheimer's differ from other forms of Alzheimer's disease?

A. The symptoms, including memory loss, are the same, regardless of when the disease strikes, said Maria Carrillo, chief science officer at the Alzheimer’s Association. The main difference is the age at which symptoms develop.

Early onset Alzheimer's strikes before age 65, often in the 40s and 50s, said James Leverenz, a neurologist and director of the Cleveland Lou Ruvo Center for Brain Health at the Cleveland Clinic.

Alzheimer's disease is normally a disease of aging. After age 65, the risk of Alzheimer's doubles every five years. After age 85, the risk reaches nearly 50%, according to the Alzheimer's Association.

People with early Alzheimer's are more likely to develop muscle twitching and spasms. They may be more active and physically fit than people with late-onset Alzheimer's disease, but decline at a faster rate, according to the Mayo Clinic.

Because people with early onset Alzheimer's often have jobs and family responsibilities, they may be more likely to feel powerless, frustrated and depressed.

Legendary Tennessee coach Pat Summitt dies at 64

Q. What happens to the brain with Alzheimer's disease?

A. A classic sign of Alzheimer's is a buildup in the brain of protein plaques and tangles. Scientists suspect these plaques and tangles are involved in killing brain cells, said Dean Hartley, director of science initiatives, medical and scientific relations at the Alzheimer's Association.

The plaques are made of a protein called beta amyloid, which seems to do the most damage when it clumps together, Hartley said. In animal experiments, beta amyloid causes another protein, called tau, to stick together, forming tangles inside the cells. These tangles then block the movement of nutrients and other essential supplies inside brain cells, killing the cells, Hartley said.

While beta amyloid appears to trigger Alzheimer's disease, the tau proteins actually kill the cells. "One is the trigger, the other is the executioner," Hartley said.

Q. What are other symptoms of early onset Alzheimer's disease?

A. In addition to memory loss, symptoms include confusion, restlessness, misplacing things, trouble performing familiar tasks, changes in personality and behavior, poor or decreased judgment, impaired communication, inability to follow directions, problems with language, impaired visuospatial skills, social withdrawal and less willingness to interact with others and a loss of motivation or initiative, according to the Mayo Clinic.

Q. How common is early onset Alzheimer's disease?

A. The disease is relatively rare, affecting about 5% of the 5 million Americans with Alzheimer's disease, according to the Alzheimer's Association.

Q. What causes early onset Alzheimer's disease?

A. Although doctors don't know all the causes, one rare form of early onset Alzheimer's disease is called familial  Alzheimer's disease, because people inherit the genes that cause it from their parents. These people tend to develop Alzheimer's symptoms in their 30s or 40s, Carrillo said. People with these genes always develop Alzheimer's.

Other people may have a variation in a gene called APOE, which increases their risk for Alzheimer's disease, but doesn't guarantee that they will develop the condition, she said. Everyone has two copies of the APOE gene, but only certain variations in the gene increase Alzheimer's risk.

Inheriting one copy of the high-risk version of APOE increases the chance of developing Alzheimer's. Inheriting two copies — one from each parent — doubles that risk, Carrillo said. Variations in this gene are involved in 20% to 25% of Alzheimer's cases.

Q. Beyond the mental decline, how does Alzheimer's affect people physically?

A. People forget not just words, but how to perform basic tasks, such as dressing themselves or using the bathroom, Carrillo said. Eventually, people forget how to walk and end up bedridden. They may need their food to be liquified because they can't chew. They develop problems with basic bodily functions, such as swallowing, so that food or saliva gets into their lungs. That can lead to infections such as pneumonia, which kills many people with Alzheimer's, Carrillo said.

Obama: Pat Summitt was a role model for my daughters

Q. What treatments are available?

A. The Food and Drug Administration has approved five drugs to treat the symptoms of Alzheimer's, according to the Alzheimer's Association. They can help improve memory and thinking problems in about half of those who take them. None of the drugs slow the progress of the disease or help people live longer. There is no cure for Alzheimer's.

Q. How do doctors diagnose Alzheimer's?

A. Many things can cause mental confusion and memory problems, such as strokes, brain tumors, certain medications, infections or a condition called hydrocephalus, in which fluid accumulates in the brain, Leverenz said. Doctors need to perform a variety of tests to find out if a person's memory problems are truly caused by Alzheimer's.

Not all dementia is caused by Alzheimer's disease, Carrillo said. Dementia also can be caused by strokes or mini strokes that kill brain cells over time.

Doctors diagnose Alzheimer's by taking a medical history, conducting memory tests, performing a physical and neurological exam, running blood tests and scanning the brain with procedures such as PET scans, according to the Alzheimer's Association. PET scans can detect amyloid proteins in the brain, a sign of Alzheimer's, Carrillo said.

Q. What progress is being made against Alzheimer's?

A. Doctors hope to treat the underlying causes of Alzheimer's, not just its symptoms.

Many experimental drugs aim to stop the creation of the brain plaques and tangles that are a hallmark of Alzheimer's disease, according to the Alzheimer's Association. Future treatments could include a cocktail of medications, similar to current state-of-the-art treatments for AIDS and certain cancers.

Scientists are also testing drugs aimed at Alzheimer's in people whose brains scans suggest they're at high risk, even though they don't have any symptoms of the disease.

Congress recently increased federal funding for Alzheimer's research by $350 million, bringing the total to about $1 billion a year, Carrillo said. While she welcomes that increase, she said the country needs to spend $2 billion a year on Alzheimer's research to better understand the disease and how to treat it.