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Faculty Spotlight: Brenda Plassman, PhD

Thursday, July 5, 2018

Brenda Plassman, PhD, became interested in dementia after studying a cohort of twin World War II veterans. In this group, some men developed Alzheimer’s disease even as their identical twins did not. Now at the Alzheimer’s Disease Research Center, she is studying the complex, interacting factors that cause Alzheimer’s disease. In this week’s Faculty Spotlight interview, Plassman talks to us about these factors, predicts trends in the measurement of dementia over the next 20 years, and discusses her recent 10-day rafting trip down the Grand Canyon.

What are your current responsibilities within the Departments of Neurology and Psychiatry and Behavioral Sciences? What does your typical day look like?

I lead multiple studies funded by National Institutes of Health and Department of Defense. I am also an Associate Director of the Bryan Alzheimer’s Disease Research Center, which involves a fair bit of administrative duties. A typical day involves interacting with members of our research group on a range of study-related issues, handling administrative and financial issues, working with post-docs and graduate students, and writing grants and manuscripts. Because our group has a number of funded studies, much of my time is dedicated to ensuring all of the studies are on track to complete the study aims.

How and when did you first get interested in psychology? What interests you the most about dementia, aging and cognition?
My interest in cognitive neuroscience was piqued when I took courses taught by Ralph Reitan, PhD, one of the pioneers in the field of neuropsychology. This interest became more focused on dementia when I came to Duke and worked with John Breitner, MD, and Kathie Welsh-Bohmer, PhD on the Duke Twin Study of WWII veterans. Studying twins highlighted the complexity of Alzheimer’s disease. In the cohort we studied, there were monozygotic twin pairs who remained discordant for Alzheimer’s disease for many years, despite the fact that they both had two APOE e4 alleles, meaning they were at increased risk of developing the disease. Thus, other factors such as environmental exposures were influencing gene expression or other mechanisms which altered risk of the disease.

Adding further complexity, the factors that influence risk of Alzheimer’s disease likely begin in early life, even though symptoms are not present until decades later. My research has focused on identifying factors throughout the lifespan that alter risk of Alzheimer’s disease. Some of my upcoming projects will focus on identifying early symptoms of the disease.  

Much of your work is at the population level, where you examine risk factors and protective factors for dementia and related conditions. What are the biggest risk factors for these conditions? What can people do to lower their risk of these conditions?

The strongest risk factors for Alzheimer’s disease and other dementias are age and genetics – two factors that are not modifiable. Several medical conditions and environmental exposures have been proposed as possible risk or protective factors for dementia. Among the more consistently reported risk factors is traumatic brain injury; while the leading protective factor is probably physical exercise. But the etiology of most types of dementia is multi-factorial, so we need to study interactions between multiple exposures, age of exposure, and genes to really understand how to prevent dementia.

We currently advise that what is good for the heart is good for the brain. But because the brain does not function in isolation from the rest of the body systems, we may expand that advice as we learn more about how each body system influences brain health.

Our research group is currently studying the association between long-term pesticide exposure and risk of dementia. Pesticides are ubiquitous in the environment; exposure is not limited to those who apply pesticides. Although pesticides alone may not lead to dementia, they may work in combination with selected genes and other factors to increase risk of dementia.

How have epidemiological trends for dementia and related conditions changed since the beginning of your career? What trends do you see coming over the next 20 years?

In recent years, a number of research groups have reported that the prevalence and incidence rates of Alzheimer’s disease and dementia have been declining. However, some of these studies classify individuals as demented based on very limited information, such as just a brief cognitive screening measure. In addition, some of the studies have shown that there has not been a corresponding decrease in dementia-related risk factors that would explain the reported decline in rates of dementia. Thus, it seems prudent to view reports of a declining trend in rates of dementia with a bit of healthy skepticism.   

I think in the next 20 years, we will see a move toward more objective or quantitative measurement of potential risk or protective factors for dementia, and a push to more systematically investigate the link between exposure and biomarkers for specific types of dementia. 

What passions or hobbies do you have outside of the Department?

I enjoy spending time with family and traveling. I also enjoy swimming and bicycling. I recently went on a bucket-list trip. Fifteen family members and I did a 10-day rafting trip down the Colorado River through the entire Grand Canyon.

I just participated in a bike ride for the Alzheimer’s Association’s The Longest Day event. The event raises funds to support education and research for Alzheimer’s disease. The Bryan ADRC has a team who biked 50+ miles on June 23 as one of many events around the country for The Longest Day.

B Plassman

Plassman, left, enduring the North Carolina summer during the Alzheimer's Association's The Longest Day fundraiser.