University Times

Increasingly, studies have shown, people are seeking health-related information. A recent Pew Internet study found that 80 percent of Americans with Internet access turn to the web for answers to their medical and health questions.

But three-quarters of consumers fail to check how reliable and how current that information is, the study revealed.

In an effort to detangle some of the overload of health information that is out there, this occasional University Times series, On Health, is turning to Pitt experts for current — and reliable — information on some of today’s major health-related topics.

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Beware the gathering storm: According to the Alzheimer’s Association, Alzheimer’s disease (AD) strikes someone every 71 seconds; it currently affects more than 5.2 million Americans and more than 25 million people worldwide.

A form of dementia, Alzheimer’s is an irreversible neurodegenerative disease that is not a normal part of aging. The disease grows progressively worse over time, slowly destroying memory and thinking skills and eventually interfering with the ability to carry out simple tasks. AD also is fatal: Today it’s the seventh-leading cause of death in the United States, according to the National Institute on Aging.

The Alzheimer’s Association estimates that by 2050, as many as 16 million Americans could be suffering from AD, which is the most common form of dementia, accounting for about 70-75 percent of cases.

That fact, coupled with the 10-15 year average duration for the disease and the enormous costs associated with caring for AD patients, could bankrupt Medicare by the middle of the century, some experts believe.

That speaks to the urgent need for more laboratory research, clinical trials and funding, AD experts at Pitt said in a recent series of interviews with the University Times.

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Alzheimer’s disease was named after German psychiatrist and neuropathologist Alois Alzheimer, who first described the condition in 1906 after noticing during an autopsy changes in the brain of a woman who had exhibited symptoms of memory loss, language difficulties and unpredictable behavior.

As he examined her brain, Alzheimer discovered many abnormal clumps, called amyloid plaques, and tangled bundles of fibers, called neuro-fibrillary tangles. Plaques and tangles in the brain are two of the main features of Alzheimer’s disease. The third is the loss of connections between nerve cells, or neurons, in the brain.

What triggers the onset of Alzheimer’s still is unknown. However, it is known that brain damage can begin as many as 10-20 years before symptoms present, as tangles begin to develop deep in the entorhinal cortex (the brain’s network for memory) and plaques form in other areas of the brain. As more plaques and tangles form, healthy neurons begin to work less efficiently, gradually losing their ability to function and eventually dying. This damaging process spreads to the hippocampus, the area of the brain essential to forming memories. As the death of neurons increases, affected brain regions begin to shrink. By the final stage of Alzheimer’s, damage is widespread and brain tissue has shrunk significantly.

While Alzheimer’s disease has been recognized for more than 100 years, its causes and cure remain elusive, frustrating researchers, doctors and health care workers alike.

According to the Alzheimer’s Disease Education and Referral Center, part of the National Institute on Aging, there are two main kinds of Alzheimer’s. About 95 percent of the AD cases are termed late-onset Alzheimer’s, rarely occurring before age 60 and most prevalent in those age 80 and older.

The other type, early-onset Alzheimer’s, is believed to be a genetic disorder and typically develops in people age 30-60. Some cases of early-onset AD, known as familial Alzheimer’s disease, are inherited, caused by genetic mutations of one of three chromosomes leading to the formation of abnormal proteins. These mutations are not present in late-onset Alzheimer’s.

Currently, AD can be diagnosed definitively only during an autopsy, but that may be changing. The Food and Drug Administration now is considering approval of an imaging test to detect the plaque buildup in the brain that characterizes the disease. Even without the test, scientists now have several methods to help them determine with about 90 percent accuracy whether a person who is having memory problems has “possible” Alzheimer’s disease (the dementia could be due to another cause, such as depression or drug interaction) or “probable” Alzheimer’s disease (no other cause for the dementia can be found).

Most diagnostic uncertainty arises from the difficulty of distinguishing Alzheimer’s disease from other types of dementia, such as vascular dementia, fronto-temporal dementia, Lewy body dementia, Creutzfeldt-Jakob disease and Parkinson’s disease.

According to the Alzheimer’s Disease Education and Referral Center, criteria for an Alzheimer’s diagnosis include a decline in memory coupled with at least one of the following: difficulty with language or communication; difficulty with everyday activities, or difficulty with one’s ability to perceive the world accurately.

Diagnosis of Alzheimer’s typically involves a thorough review of a patient’s medical history and a comprehensive evaluation including medical, neurological, psychiatric, social and cognitive assessments to determine the level of memory deficiency and the overall function of the mind and nervous system.

Such evaluations are conducted regularly at Pitt’s Alzheimer Disease Research Center (ADRC), a cluster of more than 30 affiliated Alzheimer’s experts from various parts of the health care spectrum.

Founded in 1985, ADRC’s overall objective is to study the changes in the brain of Alzheimer’s disease patients with the aim of improving the reliability of diagnosis of AD and developing effective treatment strategies.

ADRC is funded by the National Institute on Aging.

—Peter Hart