Speaking of Psychology: Protecting your aging brain, with Glenn E. Smith, PhD

Research into effective ways to prevent or slow down the onset of dementia and Alzheimer’s disease has come a long way, according to researcher and neuropsychologist Glenn E. Smith, PhD. In this episode, he discusses the causes of dementia as well as the effectiveness of activities such as physical exercise and brain training games in preventing it.

Glenn E. Smith, PhD, is a neuropsychologist at the Mayo College of Medicineopens in new window in Minnesota and a principal investigator of a study titled “Comparative Effectiveness of Behavioral Interventions to Prevent or Delay Dementia.” He is also a member of the American Psychological Association’s Committee on Aging. 

Smith received his PhD in clinical psychology from the University of Nebraska. He completed an internship in neuropsychology-geropsychology at UCLA's Neuropsychiatric Institute and a post-doctoral fellowship in clinical neuropsychology and rehabilitation at the Mayo Medical School. He is past president of APA's Div. 40 (Clinical Neuropsychology) and the American Board of Clinical Neuropsychology.

Audrey Hamilton: More than five million Americans are living with Alzheimer’s disease, making it the most common form of dementia. There is no cure. But psychologists and other researchers have been studying ways to prevent Alzheimer’s disease and other dementia-related disorders, including the use of brain-training games and physical exercise. But do they work? In this episode, we talk with a psychologist who studies the effectiveness of these treatments. I’m Audrey Hamilton and this is “Speaking of Psychology.”

Glenn Smith is a neuropsychologist at Mayo Clinic in Minnesota and a principal investigator of a study titled “Comparative Effectiveness of Behavioral Interventions to Prevent or Delay Dementia.” He is also a member of the American Psychological Association’s Committee on Aging. His research focuses on not only treating dementia and Alzheimer’s, but on how to prevent these brain disorders. Welcome, Dr. Smith. 

Glenn Smith: Thank you. It’s a pleasure to be here. 

Audrey Hamilton: Some people can live to 100 and never show signs of dementia or other cognitive impairments. Others can be severely debilitated by these diseases in their 80s or even younger. What do we know about why certain people develop dementia – particularly dementia associated with Alzheimer’s? 

Glenn Smith: Well, the honest answer is we don’t know enough. We’re trying to learn more about this issue of why some people have a predilection to develop dementia.

A few of the things we do know – we have some reasonable ideas about how the Alzheimer’s disease develops in the brain. We believe the current theories are that there is a protein called amyloid beta that deposits in the brain and it seems that it’s toxic to neurons – brain cells – and so amyloid deposition in the brain can lead to cell death and twisting and tangling of brain cell processes so you end up with the plaques and tangles of Alzheimer’s disease.

Now one of the really challenging parts of the disorder is that the amount of brain pathology that accumulates seems pretty strongly correlated with the degree of thinking, cognitive and functional impairments that people have. We’ve followed people from their 60s, 70s and 80s, annually, with evaluations of their thinking and functioning and we’ll see two trajectories – some people progress to cognitive impairment and dementia and then they die and they’ve given us permission to do autopsy. And those folks will have Alzheimer’s disease or other pathologies. One in five people who have been in this longitudinal study, when they die, even though they remain cognitively and functionally normal throughout their life, they have plaque and tangle disease in their brain.

So one of the intriguing, perplexing questions we’re trying to understand is, how is that possible? How did those people remain resilient to that amount of disease in their brain? And psychologists, most notably a man named Yaakov Stern from Columbia University, have talked about this idea of cognitive reserve, the ability to show resilience in the face of brain pathology. So, we’re trying to understand more about what are factors that contribute to cognitive reserve and is cognitive reserve malleable? Can we enhance it somehow? 

Audrey Hamilton: Let’s talk now about the research into the ability to prevent dementia onset. Are there drugs available? What about lifestyle changes? 

Glenn Smith: So, on the medication front, there is of course a class of drugs that’s approved for Alzheimer’s disease. Now this class of drugs has the effect of impacting levels of the neurotransmitter acetylcholine in the brain. That class of drugs was created from an earlier model of how we thought Alzheimer’s disease develops. And those class of drugs, while they are FDA-approved for Alzheimer’s disease, have proven to have limited effectiveness.

On the lifestyle front, the notion is emerging is that what’s good for the heart is good for the brain. So all of those things that we’ve tried to attend to on the public health front to reduce the risk of stroke and heart attack seem to have utility in reducing the risk of dementia as well. That includes things like physical activity level, diet and notably now some evidence that certain patterns of cognitive engagement – your lifestyle around cognitively stimulating activities – also seem to be associated with dementia risk, so people with more advanced levels of educational attainment or people that have engaged perhaps in their lifetime in learning musical instruments or foreign languages or those kinds of cognitive enrichment activities seem to be at lower risk. 

Audrey Hamilton: So if someone has already noticed signs of dementia, is it too late to engage in some of these treatments? 

Glenn Smith: We don’t think so and that’s really the genesis of that research project that you mentioned that we were fortunate to have funded by an organization called the Patient Centered Outcomes Research Institute. We’re trying to see if it’s possible, as I mentioned earlier, to impact this notion of cognitive reserves. So there is research to suggest that even if you already have the condition called mild cognitive impairment – there is some research to suggest that those folks, those people who engage in those lifestyle modifications, even after they’ve developed the diagnosis of mild cognitive impairment, at least have a longer time to progress to the full dementia syndrome. 

Audrey Hamilton: What about these adult brain training games? They’re really popular right now. You see ads for them. Do they have any scientifically measurable effect on cognition or memory? 

Glenn Smith: Well, they do and it’s an interesting time in that regard because a group of scientists in this area have just put out a statement that has been associated with the Stanford Center for Longevity, cautioning the general public about the utility of these kinds of tools.

But I think the meta-analyses of these different programs suggest that there is some measurable signal of cognitive improvement on certain programs that have been developed, especially those that target processing speed because processing speed is what changes as we age and as we age, we know this is kind of the fundamental deficit that normally aging people have.

So imagine being introduced to four people at a cocktail party. No matter if you’re 35 or 85, someone’s probably going to introduce you to those four people at the same rate. And at 35, you’ll be better able to hear that name. At age 85, you can do all those same tasks, but since they occur at a slower rate, by the time you get to the fourth person, you may not have the capacity to process it as deeply or as richly.

So that’s what gives people the experience of perhaps having memory failure. “Why can’t I remember that fourth person’s name? I used to be able to do that.” And it’s not really a memory failure, so much.

So a number of these different computer training programs are targeting that aspect of brain functioning. And what they tend to do is first – and the critique of them is first, primarily what they make you better at is playing computerized brain games.

But a few studies have shown some transfer to other areas of working memory. In our study, people did report better functioning in their daily life, but better functioning in your daily life is really hard to measure. Now all of this as it pertains to prevention of dementia gets a little more complicated because certainly we’re not at a place where we can say “Glenn Smith, if he does brain training games for the next 25 years, we can guarantee that he won’t get dementia.”

But, you know, prevention as a concept is a concept that we really apply at the population level. And similarly, in my opinion, if we engage both physical activity and cognitive stimulation, including these brain training games in a population-wide level, we have the potential to see fewer numbers of dementia in the population at large and that’s really the kind of prevention we’re talking about.

So one of the challenges in this area is really what do we mean by prevention? You know, we can prevent polio in a person by giving them a vaccine. We’re certainly not at that level in the area of dementia, but we can prevent the numbers of cases of heart attack and stroke by eliminating smoking and improving physical activity and diet. And I believe that that potential is there in the area of dementia as well. 

Audrey Hamilton: Well, great. Thank you so much for joining us, Dr. Smith. This has been very, very informative. Thank you. 

Glenn Smith: My pleasure. Thank you for the opportunity. 

Audrey Hamilton: For more information on dementia and Alzheimer’s disease, visit our website . With the American Psychological Association’s “Speaking of Psychology,” I’m Audrey Hamilton.