By Sara Harris
July 14, 2010
Denise Cortis Park, Ph.D., Professor of Behavioral and Brain Sciences, The University of Texas at Dallas
Dr. Denise Park
With its rapidly aging society, the United States faces an increasingly pressing issue: how to stave off memory lapses and the loss of mental agility as well as the brain diseases associated with senior years. Dr. Denise Park, Director of the Center for Vital Longevity, employs innovative brain imaging tools to understand how our brains change as we age. Her findings will help develop diagnostic tests for detecting Alzheimer's disease, and they should provide a better understanding of strategies for maintaining a healthy mind at every stage of life.
The Problem: Aging brings both richer memories and lapses of memory. On the one hand, we experience wisdom and insight; on the other, we're more susceptible to normal age-related forgetfulness and, in many cases, to Alzheimer's disease or other dementias. Could neuroscientists uncover the secrets of the aging mind, ultimately providing the tools and strategies needed to optimize the way our brains function and slow down or even prevent the progression of Alzheimer's disease?
In 2006, the first of the baby boomers turned 60. By 2030, 72 million people—almost 1 out of 5 Americans in that year—will be 65 years or older, almost twice the figure today. As Americans live longer, questions on aging have become increasingly urgent.
Finding a Solution: With new brain imaging tools, funding from the Recovery Act, and two ongoing long-term studies, Dr. Park is very much engaged in the search for answers.
One of the initiatives in which she is involved, the Dallas Lifespan Brain Study, is a comprehensive examination of the brain and its function across the lifespan—with the aim of identifying patterns of healthy aging as well as flagging changes that lead to disease. This 10-year study pairs cognitive tests with genetic examinations, and it includes measurements of brain structure and function using magnetic resonance imaging (MRI) in 350 volunteers, from people in their 20s to those in their 80s. The approach represents a shift in thinking, Dr. Park said. In contrast to an earlier focus on what goes wrong to cause cognitive decline and disease, the scientific community now is rallying to explore what goes right. There is a realization that “we need to make a parallel investment in the study of healthy aging that we have made in studying the pathology of aging,” she said.
Recent developments allow Dr. Park to add another layer to her lifespan study: amyloid imaging. The amyloid protein forms on the brain and comprises the characteristic plaques in the brains of people who suffer from Alzheimer's disease. Until recently, however, the plaques could be observed only after a person died. With the availability of a new radioactive compound that binds to the plaques when injected, the brains of healthy living people can now be safely scanned, and scientists can observe which adults have amyloid plaques on their brain, enabling researchers to correlate the presence of amyloid with cognitive abilities.
In partnership with Avid Radiopharmaceuticals, the company that makes the compound that binds to amyloid in the brain, Dr. Park has begun adding amyloid imaging to the studies performed on participants in the Dallas Lifespan Brain Study. She and her team presented their first results in July 2010 at the International Congress on Alzheimer's Disease; they reported that about 25 percent of healthy older adults have amyloid and that this may be a harbinger of Alzheimer's disease many years before it is manifested in behavior. Ultimately, the work may result in the most complete picture of cognitive aging to date and produce the first measurements of amyloid in middle age. “I have never in my career wanted to do a study as much as I wanted to do this one, as it allows us to learn if we can predict the course of aging years into the future,” Park said.
The second question—Can we modify the brain to prevent memory loss, lags in processing, and other signs of cognitive decline?—is being tested simultaneously in another study by Park: the Synapse Project.
The Recovery Act's Challenge Grants focus on high-priority research areas and approaches—in this case, comparing specific strategies for preventing cognitive decline. The Synapse Project enrolls older participants in mentally stimulating activities for many months. Participants spend upward of 20 hours a week learning digital photography or participating in quilting classes. The cognitive function of these participants is contrasted with that of older adults who engage in less stimulating activities, such as spending time in social settings or engaging in relatively low-key challenges at home, such as working crossword puzzles or watching intellectually stimulating movies. With the new funding, Dr. Park will add a walking group to compare the effects on improvement in cognition between exercise and intellectually stimulating activities. Some participants will receive both exercise and mental stimulation to see if this produces maximal improvement.
Research shows exercise can help people keep their minds sharp by increasing blood flow to the brain. Learning a skill and maintaining an active social life have also been shown to be good strategies.
Although we may not consider socializing to be a form of intellectual stimulation, meeting new people and developing relationships requires remembering names, listening attentively to stories, and responding. “It's possible we underestimate the value of being socially engaged,” Park said.
In the Synapse Project, this kind of engagement will be compared with challenges that stress specific mental tasks or motor skills and now, walking.
Dr. Park tests volunteers' memory and other cognitive skills in her studies of aging.
Perhaps one of these alternatives will come out on top. Is one more effective than the others? How much would people benefit from combining two of them? The answers to these questions may one day shape our senior years.
How This Funding Helps: The Synapse Project is one of very few studies that attempts to see how changing to a stimulating lifestyle enhances cognition, and it allows for a direct comparison of whether intellectual stimulation, social interaction, or exercise is best for preventing cognitive decline. Historically, such comparisons have been difficult, as, for example, establishing experimental groups to measure the effects of exercise is complicated and expensive. As a result, studies comparing mental stimulation and physical exertion have been limited under typical avenues of funding. In short, Dr. Park noted, the extensions of her ongoing research “would never have happened” without stimulus funding.
Similarly, without stimulus funding and the partnership with Avid, it would have been prohibitively expensive to learn about the frequency of amyloid deposits on the brains of still healthy adults and how the brain changes and responds to this event.
As a result of the funding, Dr. Park employs two new postdoctoral researchers and other staff in her laboratory. One researcher, initially hired on a temporary basis, would have lost her job if the funding hadn't come through. Altogether, Dr. Park estimated, ARRA funding allowed her to nearly double the size of her laboratory staff. Meet Dr. Park and two of her research assistants.
After Two Years ... The enhancements Dr. Park initiated in January generated compelling results within months. For example, the presence of amyloid in the brains of healthy adults appears to exert an effect on basic cognitive measures such as processing speed and working memory. Higher-level functions such as verbal memory and reasoning also appear to be affected. Other early findings in healthy adults suggest that the presence of amyloid correlates with less brain activity during specific tasks performed for the study.
Results like these could help researchers pin down what it is that triggers cognitive decline in Alzheimer's disease. Paired with developments in medication, doctors ultimately could use the techniques Dr. Park develops to check for specific signs of aging and prescribe appropriate drugs to control amyloid deposits and maintain cognitive health. One day this combination may be as routine—and effective—as blood tests and statins are for high cholesterol today, Park said. Findings from the Synapse study comparing learning, social engagement, and exercise could help doctors define the most effective strategies for maintaining brain health in older adults.
Recovery Act Investment: ARRA funding supported three lines of research: “Active Interventions for the Aging Mind” was awarded $290,712 in fiscal 2009 from the National Institute on Aging (NIA). NIA also funded “Neuroimaging of Dedifferentiation and Memory Across the Lifespan” ($894,213) and “Impact of Exercise and Engagement on Cognition in Older Adults” ($392,071).