With the "graying" of society, people are living much longer. This increased lifespan is not without accompanying health problems. Alzheimer's disease, osteoporosis, and cancer are three pathological states the incidence of which seems to increase rapidly with age. The following research update covers Alzheimer's disease--a progressive form of dementia most often associated with aging.

Dementia is a biochemically-mediated mental disorder indicated by a generalized loss of intellectual ability. This involves impairment of memory, judgment, and abstract thinking. Changes in personality are also associated with dementia.

Dementia is not a specific disease. It is a set of symptoms found in a variety of pathological conditions. These include Alzheimer's disease, Huntington's disease, stroke, depression, infections of the brain, and trauma to the head. The most common cause of dementia is Alzheimer's disease.

Alzheimer's disease is a progressive, degenerative disease of the brain. Its etiology is just now starting to be understood. It is characterized by a diffuse atrophy throughout the cerebral cortex with attendant, highly distinctive pathological changes. These changes include senile plaques and neurofibrillary tangles.

Senile plaques are microscopic lesions made up of fragmented axon terminals and dendrites enveloping a core of beta-amyloid protein. Neurofibrillary tangles are intracellular clumps or knots of neurofibrils within individual diseased neurons.

Many of the degenerating neurons in Alzheimer's disease are cholinergic (acetylcholine-containing) neurons. There is a loss of choline acetyltransferase enzymatic activity in the cerebral cortex.

The first signs of the disease are a slight loss of memory and minor changes in personality. However, the deterioration is progressive over the next 5 to 10 years resulting in profound dementia. The age of onset varies, but the risk factors increase with age.

Alzheimer's disease most often strikes people 65 and older; however, people much younger can be affected. Ten percent of people over 65 and up to half of those 85 or older have Alzheimer's disease.

There are over 4 million Americans with Alzheimer's disease. This number is projected to climb to a staggering 14 million by the middle of the 21st century. The disease claims over 100,000 lives per year in the U.S. making it the 4th leading cause of death for adults.

There is no cure yet for Alzheimer's disease. But in mid-November of 1994 a team of researchers at the Harvard Medical School announced a new diagnostic test for the disease. The test is relatively simple and may be able to detect Alzheimer's disease in its early stages.

The progressive nature of Alzheimer's disease ultimately results in patients becoming unable to care for themselves. But a patient can live for up to 20 years after the onset of the condition. This generates a cost to society of $100 billion per year.

The Alzheimer's Association has developed a checklist of 10 common symptoms for Alzheimer's disease. Taken alone, some of these symptoms could be indicative of a number of disorders. However, if someone you know displays several or more of the symptoms, the individual should see a physician for a definitive diagnosis.

The national headquarters of the Alzheimer's Association is located at 919 N. Michigan Ave., Suite 1000, Chicago, IL 60611-1676. They can be reached at 1-800-272-3900.

1. Recent memory loss that affects job skills
2. Difficulty performing familiar tasks
3. Problems with language
4. Disorientation of time and place
5. Poor or decreased judgment
6. Problems with abstract thinking
7. Misplacing things
8. Changes in mood or behavior
9. Changes in personality
10. Loss of initiative

Reprinted with permission of The Alzheimer's Association.

The citations in this hot topic, together with full abstracts, are available as part of the Life Sciences Collection (online, magnetic tape, CD-ROM, and via the Internet) and in the CSA Neurosciences Abstracts print journal.

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Editor

Frederic A. Spangler, Ph.D.

• CSA Senior Science and Internet Editor
  and Web Resources Manager

• B.S. (Biology; minor concentrations in Mathematics, Biophysics, and Earth Sciences), Pennsylvania State University, University Park, Pennsylvania

• Ph.D. (Physiology and Biophysics; thesis research area: Biochemical Endocrinology; minor fields of study: Neurobiology, Pharmacology), The Georgetown University Medical Center, Washington, DC

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