Baycrest Breakthroughs 2008

Slowing down Alzheimer’s Disease

Researchers at Baycrest have made great strides in recent years in understanding Alzheimer’s, but so much more is needed to beat this crippling disease.

Alzheimer’s disease is the most common form of dementia – a term used for a number of conditions that lead to a progressive deterioration in our ability to think, remember and perform daily tasks. Researchers are discovering that long before symptoms of the disease appear there are small changes in the brain that may foretell the onset of dementia.

It is therefore vitally important to identify these brain changes as early as possible so that medical intervention can be quickly and aggressively put into effect. A recent Baycrest study has been targeting this issue and a new diagnostic breakthrough tool offers some hope for a more timely intervention.

Dr. Paul Verhoeff is a clinician-scientist at Baycrest’s Kunin-Lunenfeld Applied Research Unit (KLARU) and staff psychiatrist at Baycrest’s Brain Health Centre. “I could not imagine anything worse happening to me than a decline in my brain functioning,” he says, when asked what drew him to this area of research. “The brain defines who we are and helps us to maintain our independence,” he says. Nevertheless, he is anxious to point out that, while there is to date no cure for the disease, there have been important advances made in recent years.

Gauging the Risk

“Age is the main risk factor for Alzheimer’s disease,” he explains. “People, particularly women, are living longer in our society and Alzheimer’s is a bit more prevalent in women than in men. But the increased prevalence may also be gender related, as opposed to age related.”

Genetic predisposition is another factor in determining risk. Early symptoms of Alzheimer’s are not always directly related to deterioration in cognition. An uncharacteristic apathy or an increase in anxiety levels can sometimes be early signs of the disease.

Researchers have discovered a link between depression and Alzheimer’s, says Dr. Verhoeff, to the extent that people with a history of depression have a two-fold greater risk of developing the disease.

Clinical guidelines mark the onset of Alzheimer’s from age 45, but physicians sometimes see people with dementia even earlier, particularly those with a hereditary factor. “Most people are diagnosed with Alzheimer’s after the age of 65,” Dr. Verhoeff reports. “If it occurs before that age, it is considered early onset.”

The numbers of people afflicted with this debilitating disease are quite stark: at age 60, Alzheimer’s affects approximately one per cent of the population and it doubles every five years, so that if at age 65 the chance is one in 20, at age 75 it would be one in 10, while at 85 it would be one in four and at 90 the prevalence spikes to one in two people.

Reducing the Odds

With such dramatic statistics, you might be wondering if there is any good news out there.

Yes, say researchers and clinicians at Baycrest – it appears that our lifestyle can affect our ability to withstand Alzheimer’s. “It is important to mention that there is some hope in the fact that you can probably stave off the onset of Alzheimer’s by making lifestyle changes,” maintains Dr. Verhoeff.

Epidemiological studies suggest that, as with our bodies, the ‘use it or lose it’ approach is worth adopting for brain health. Studies show a decreased risk for dementia in older adults who exercise their brain – and the earlier you begin the better.

Researchers have learned that a lifestyle of greater mental challenge can actually affect the system of connections in our brain, thereby giving us more ‘muscle power’ to withstand cognitive deterioration. Put another way, Dr. Verhoeff says, “We might need greater brain damage before we see or experience the tell-tale signs of Alzheimer’s or other dementias.”

In fact, researchers have noted that people with higher education and those who remain intellectually active appear to have greater protection from the disease. Crossword puzzles, chess, learning a language or a musical instrument – these are all brain-challenging and brain-stimulating activities.

In the same vein, people who perform regular physical exercise are less likely to develop heart disease or stroke – both of which are associated with an increased risk of dementia. A heart healthy diet, exercise and active social life are also protective factors that positively affect brain health.

The Importance of Developing Early Diagnostic Tools

Although early detection and aggressive treatments to preserve cognitive function are vital for Alzheimer’s sufferers, to date doctors have had no laboratory test either for diagnosing or for monitoring the progression of the disease.

Together with researchers at the Centre for Addiction and Mental Health (CAMH), and the University of Toronto, Dr. Verhoeff has been engaged in research that involves using Positron Emission Tomography (PET) scanning to detect brain deposits associated with Alzheimer's.

Previous research has revealed that these deposits, known as beta-amyloid plaques, were unusually high when autopsies were performed on Alzheimer’s victims. Scientists believe that abnormally high levels of beta-amyloid are found in the brains of Alzheimer’s sufferers well before cognitive symptoms appear.

Until recently, no reliable test for detecting this substance in the brain existed, but a research study by Dr.Verhoeff and his partners successfully injected patients with a compound that attaches itself to amyloid deposits and sends out harmless radioactive signals that can be detected with a PET scan.

As with the levels found in Alzheimer’s victims, abnormally high beta-amyloid levels were found in living subjects and it is hoped that this promising new compound might be a reliable predictor of early changes in the brain that might lead to Alzheimer’s. Such a predictor would help doctors arrive at an early diagnosis of Alzheimer’s, which would, Dr. Verhoeff reports, “allow for a more timely initiation of preventative treatment strategies aimed at delaying the onset and decreasing the severity of Azheimer’s disease.”

If you would like to know more about funding research in Alzheimer's and related diseases at Baycrest, please contact Florence Weinberger of the Baycrest Foundation at 416-785-2500, ext. 2055.

Related Links

• Memory and Aging at Baycrest
• Sam and Ida Ross Memory Clinic
• Memory & Aging Program
• Alzheimer's - Health Information  
• Are my memory lapses a sign of Alzheimer's?
• Caring for Your Loved One