The New Science of Alzheimer's

Imagine your brain as a house filled with lights. Now imagine someone turning off the lights one by one. That's what Alzheimer's disease does. It turns off the lights so that the flow of ideas, emotions and memories from one room to the next slows and eventually ceases. And sadly--as anyone who has ever watched a parent, a sibling, a spouse succumb to the spreading darkness knows--there is no way to stop the lights from turning off, no way to switch them back on once they've grown dim. At least not yet.

But sooner than one might have dared hope, predicts Harvard University neurologist Dr. Dennis Selkoe, Alzheimer's disease will shed the veneer of invincibility that today makes it such a terrifying affliction. Medical practitioners, he believes, will shortly have on hand not one but several drugs capable of slowing--and perhaps even halting--the progression of the disease. Best of all, a better understanding of genetic and environmental risk factors will lead to much earlier diagnosis, so that patients will receive treatment long before their brains start to fade.

Could Selkoe possibly be right? Could it really be that patients and physicians alike will come to view Alzheimer's disease in much the same way they now view heart disease--as a serious illness that can be treated and even prevented? That's what Alzheimer's experts are fervently hoping. Already, they observe, an estimated 20 million people are suffering from the disease worldwide--4 million in the U.S. alone. And as the population grows and as people live longer and longer, those numbers will explode--more than threefold by the year 2050, according to some estimates. Declares Bill Thies, the Alzheimer's Association's vice president of medical and scientific affairs: "What we are facing is an epidemic of major proportions."

This week, as Alzheimer's researchers gather from around the globe for the giant World Alzheimer Congress in Washington, there's a dawning sense that scientists could be on the verge of stemming the epidemic. In recent years, new and startling insights into Alzheimer's have started to pour out of university, government and corporate laboratories. And thanks to an influx of interest and research dollars, the pace of discovery is accelerating. Exclaims Marcelle Morrison-Bogorad, who heads the Neuroscience and Neuropsychology of Aging Program at the National Institutes of Health: "An awful lot of scientists are following an awful lot of leads, and the leads are tantalizing!"

This week, for example, scientists will describe the progress they have made tracking down genes that put people at risk for Alzheimer's disease. They will present fresh evidence that other factors--high-fat diets, for instance--may substantially elevate that risk. And most exciting of all, they will discuss the first clinical trials of compounds that target what many believe to be the cause of Alzheimer's disease--a sticky snippet of protein known as beta amyloid. A controversial yet compelling hypothesis--long championed by Selkoe, among others--contends that excessive amounts of beta amyloid are toxic to neurons in the same way that too much cholesterol is toxic to the cells in blood-vessel walls.