Alzheimers’ researchers set their sights on prevention

Kristine Berey

February 2011

Except in its rare early-onset form, Alzheimer’s is typically seen as a disease of the elderly. A probable diagnosis, confirmed only through an autopsy, is based on several factors, including rapidly advancing dementia and the presence of plaques and tangles in the brain.

New imaging techniques have made it possible to detect the likelihood of the disease developing decades before any cognitive loss appears, a leading Alzheimer’s researcher told the crowd at the Alzheimer Groupe’s Awareness conference last month.

“It’s been known for some time that you can have amyloid buildup and plaques 20 years before having any symptoms,” said Dr. Serge Gauthier, of the McGill Centre for Studies in aging. “We can do the scan at the Neuro, but do you really want to know?”

Although researchers hope that in the long run early diagnosis and early treatment “will go hand in hand,” diagnosing Alzheimer’s at a pre-clinical stage is sparking debate among researchers and policy makers. “Screening could be done but [except in special cases] it’s not advisable,” Gauthier said, explaining that such a diagnosis could adversely impact a person’s right to drive, his employment benefits and access to insurance. “Anything in a medical file, the insurance people have access to because you signed permission.”

Though PET and MRI scans can identify the hallmark lesions of the illness, it is likely but not a given that the disease will develop. As demonstrated in the now-famous Nun study, continuing since the mid-’80s, plaques and tangles can exist in the brain without cognitive loss.

Minimize risk, Dr. Serge Gauthier says. Photo: Courtesy of Alzheimer Groupe

“Having buildup doesn’t mean you will get Alzheimer’s,” Gauthier said. “This is new territory for us and we may say you have a higher risk.”

Gauthier and his team are focusing on “the worried well” and those with mild cognitive impairment (MCI), a population in which medications have not been shown to be effective so far. Such drugs as Aricept, Exelon and Reminyl seem to help more in the later stages of the illness.

“New programs looking a prevention strategies for persons at risk will be starting soon in Montreal,” Gauthier said.

Preventing Alzheimer’s, at least for now, lies in minimizing risk factors and augmenting the protective factors afforded by nutrition, lifestyle changes and physical activity. “These are things we can do right now,” Gauthier said, adding that whatever is good for the heart, is good for the brain.

Risk factors include alcohol, diet, excess weight and little mental or social stimulation, said Howard Chertkow, director of the Jewish General Memory Clinic.

He talked about the concept of “cognitive reserve,” a combination of good genes, nutrition, a nurturing environment and a good education, that is built during one’s early years. “It appears these factors may impact on Alzheimer’s,” Chertkow said. “Some have a better ability to withstand disease than others.”

Though we cannot add to our cognitive reserve, we can work to maintain what we do have, says Jens Pruessner, director of McGill Studies in Aging. “One of the main characteristics of the central nervous system is that there is very little neurogenesis. Once a neuron is lost, it’s lost. But what you might be able to do is generate more connections between the neurons you still have.” Brain fitness activities include learning an instrument, solving puzzles, gardening and being socially involved.

“It’s not a question of what you do but that you do it consistently.”

Pruessner says video games have been shown to be beneficial in terms of cognitive training. “You can improve your mental speed, memory and logical reasoning,” Pruessner said, pointing out that the McGill Studies in Aging has put an online videogame on its website. Completely free to users who are asked to register, the games also serve as research. “The project allows us to pool anonymous data, without individuals’ names,” Pruessner said.

To try out the cognitive training games, go to Prevention Of Neurodegenerative Disease in Everyone at Risk at ponder.mcgill.ca