A recent book, The End to Alzheimer’s, has become a best seller. In my next post I will discuss this book, but to understand the book and my review of it it’s necessary to know what the terms “dementia” and “Alzheimer’s” (AD) mean.

Dementia is a loss of overall brain power: reasoning, analytic thought, behavior and memory are all effected to a varying degree. Dementia may be acute or chronic; reversible or permanent; stable, improving or progressive. Many causes of dementia have been discovered but most cases, especially in the elderly, are due to some combination of vascular disease and AD.

When I was in medical school Alzheimer’s was termed pre-senile dementia. The original description was from the early 20th century: a middle aged woman developed progressive dementia and died after several years. At autopsy she had severe loss of brain tissue and unusual changes in some parts of the brain. These pathologic findings are still the definitive way to diagnose AD. In recent decades AD has become epidemic, especially in older people. Half or more of people over 85 may have AD, and AD is one of the leading causes of death in the United States.

Specific genes make development of AD more likely and there is now a lively debate on the usefulness of genetic testing for it.

BUT- some people with strong genetic patterns favoring AD never get the disease, and some people with large amounts of the diagnostic brain pathology changes at autopsy had no dementia while alive.