Researchers Working Toward Early Warning System for Alzheimerís by Gina Shaw The number of people with Alzheimerís disease worldwide is growing at such a rate that by the year 2020, experts predict that some 22 million people will have developed the disease, and by 2050, that number may climb to 45 million. Many of the millions of people who will begin a slow decline into debilitating dementia over the next few years may already have signs of the disease in their brainsóeven if they show no outward sign of memory problems. Over the past several years, researchers at the New York University School of Medicine have built a body of knowledge on Alzheimerís using magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning of the brain, which use the atrophy rate in certain parts of the brain to help predict who will develop Alzheimerís and who will not. Over the past six years, the NYU scientists have conducted regular MRI scans on 45 ìnormal elderlyî patientsóone ìbaselineî image and at least two follow-up studiesóalong with a battery of neurological and psychiatric tests. During the six-year period, 13 of the 45 study participants developed mild cognitive impairment (MCI), a form of m emory loss that is strongly associated with future Alzheimerís diseaseóand the MRI scans predicted with astounding accuracy who these individuals would be. Atrophy in the medial temporal lobe structures of the brain, which contain areas such as the hippocampus that are crucial to the formation of new memories, appeared on the MRI scans of 11 of the 13 study participants who went on to show signs of cognitive decline. ìTransition from normal aging to MCI has been largely uncharted until now. MRI shows us atrophy in the medial temporal lobe before the first signs of mild cognitive impairment appear,î said Dr. Henry Rusinek, an associate professor in NYUís Department of Radiology. ìWe have been able to show the first evidence that there is a one-year period ahead of the onset of mild cognitive impairment when we can establish with 90 percent accuracy what the future will tell in terms of cognitive decline.î These new findings build on earlier studies done at NYU that used PET scans to help predict who among a group of older people with no outward signs of memory loss would develop mild cognitive impairment and who would not. In those studies, PET scanning showed that certain study participants had a lower-than-normal rate of glucose metabolism in a particular area of the medial temporal lobe structure known as the entorhinal cortex. Three years later, all of those people had gone on to develop either MCI or Alzheimerís disease, while the study participants who had started out with normal PET scans showed no sign of mental deterioration. ìWeíre getting closer and closer to the start of the disease, indeed, finding the disease before there are symptoms,î said Dr. Mony de Leon, director of the Center for Brain Health and a professor of psychiatry at NYU. This potential Alzheimerís early warning system, much like genetic testing for progressive fatal disorders such as Huntingtonís disease, begs the question: Would you really want to know? If you and your brain have a single precious year left of working together normally, before the slow process of decline begins, would you want to make the most of that yearóor would you prefer not to be counting down the days until you can expect to start forgetting your childrenís names? It is true that there is no cure for Alzheimerís disease. But it is also true that most experts believe that early interventionóat a stage when the diseaseís characteristic amyloid ìplaquesî have done the least possible damage to the brainóholds out the best hope for slowing mental decline and, someday, perhaps stopping it in its tracks. Beating Alzheimerís ìis going to be contingent on identifying symptoms very early, before the disease has gained a foothold in the brain,î Dr. Kathleen Welsh-Bohmer of Duke Universityís Bryan Alzheimerís Disease Research Center told the 2000 World Alzheimer Congressóthe first-ever global conference on the disease. Consider the studies published earlier this year that have indicated that common over-the-counter pain relievers such as ibuprofen, known as non-steroidal anti-inflammatory drugs (NSAIDs), bind to those amyloid plaques and may actually be able to dissolve them and possibly prevent new ones. Ibuprofen as an Alzheimerís preventive is a long way from being a proven treatment, but if further study backs up these early conclusions, it may prove to be a powerful early intervention tool. And the NSAIDs are only one of many types of drugs being studied for the early treatment of Alzheimerís and other dementias. ìEarly diagnosis of Alzheimer's disease now has an underlying purpose: early therapeutic intervention at the stage where brain cell degeneration is minimal,î said Jorge R. Barrio, professor of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA, a lead investigator with the team that published the NSAID study in the journal Neuroscience in March. ìThis would provide hope to patients and families.î ìOur aim here is toward being able to test the new array of drugs designed to attack the mechanisms of plaque formation early on in the disease,î agreed Rusinek. ìThe earlier you can address this, the better.î Gina Shaw is the medical writer for The Washington Diplomat.