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Report: Rethinking Alzheimer's
(This article is an update of Dr. Goldberg's first "Senior Moments" column published here in July 1998.)
Alzheimer's disease -- a well-known cause of memory impairment in aging -- remains the most common and feared problem that we are asked and consulted about in geriatric medicine.
Although Alzheimer's disease was only "discovered" about 100 years ago, it obviously is not really a newly occurring condition, only a newly recognized or understood condition.
Certainly throughout history, people became old, feeble and confused, but they were just called "senile." And most people didn't live to be very old, so the problems of senility were uncommon and not all that important. Only since the 1960s did the medical community begin to realize that most "senile" old people really had a similar or identical condition to a disease that had been reported upon in 1907 by German pathologist Dr. Alois Alzheimer.
Since then, it has been felt that about two-thirds of elderly patients with what is now called "senile dementia" have Alzheimer's disease, and about one-third have strokes or other miscellaneous brain diseases.
True (pathological) Alzheimer's disease consists of abnormal deposits called "plaques and tangles" in the brain cells that can only be diagnosed with certainty through biopsy or autopsy.
But a study announced at the annual meeting of the American Academy of Neurology in Hawaii just weeks ago reported that Alzheimer's is often misdiagnosed. Many people labeled with it actually do not have it.
They do have dementia (memory impairment), but the actual underlying cause in the brain may be more variable and unpredictable, according to the latest research.
In the "Honolulu-Asia Aging Study," Dr. Lon White and colleagues studied the brains of several hundred elderly individuals who died after having extensive psychological testing to diagnose dementia.
Some of the patients diagnosed with the disease did have the expected "plaques and tangles" in their brain cells, but only a minority had just that. Most had other pathologies, either alone or in combination, including atherosclerosis (hardening of the arteries, micro-infarcts, small strokes), Parkinsonian "Lewy Bodies," nonspecific brain atrophy (loss of brain tissue) or other abnormalities.
Not surprisingly, most patients had more than just one thing wrong with their brains, and the more things that were wrong, the more likely dementia.
So the conclusion is not that these patients weren't suffering from dementia, but that it was seldom really "just Alzheimer's." Micro-infracts due to hardening of the arteries -- typical of people with diabetes, high cholesterol, high blood pressure and coronary heart disease -- was very common.
Whether the current medicines for Alzheimer's, such as Aricept and Namenda, helped these more complex situations is unknown.
But this finding also contains some hope. New diagnostic criteria for Alzheimer's and dementia were recently released by the Alzheimer's Association and National Institute on Aging, which may help health care providers make a more accurate diagnosis.
Further, many other studies have recently found that most cardiovascular risk factors and conditions are related to dementia. Obesity, diabetes, hypertension and high cholesterol have all been found to cause strokes and dementia, as well as heart disease.
Aggressive prevention and control of these conditions may reduce the risk of developing Alzheimer's, as well as vascular dementia.
Indeed, in another study announced at the April meeting and published in the journal Neurology, treating high blood pressure, diabetes and cholesterol did reduce the risk of Alzheimer's in people starting to show signs of memory problems.
Dr. Todd Goldberg, a nationally prominent geriatrician and former medical director of Pauls Run in Philadelphia, is associate professor/director of geriatrics, West Virginia University/Charleston Area Medical Center in Charleston, W.Va.