Matt Grilli, PhD, Director of the Human Memory Lab at the University of Arizona talks about a test to predict Alzheimer’s.
Interview conducted by Ivanhoe Broadcast News in August 2018.
We’re talking about diagnosing the risk for Alzheimer’s, tell me about your memory study.
Dr. Grilli: Sure. For a bit of background, Alzheimer’s disease is a condition that gradually affects the health of the brain. We can think about the brain as a sort of city built of warehouses, and roads that connect these warehouses and allow us to travel between them. We access these warehouses to look on our knowledge, to retrieve recent and remote memories and to take note of our ongoing sensory experiences. Through this we’re able to manage a variety of complex activities of daily living. From paying attention to the road while we drive from one location to another, to remembering to take our medication later in the day or balancing a checkbook and paying our bills on time. With Alzheimer’s disease, it’s a condition that gradually shuts down these warehouses and closes the roads. And once it begins it’s something that unfortunately we can’t stop. So currently there isn’t a cure for this disease. That being said we know that early diagnosis of this disease is really key for trying to treat the symptoms, for helping with providing resources to patients and their families. Whether that be social resources, medical or educational. Things like local chapters of an Alzheimer’s Association. And what we’ve also learned over the years is that neuropsychologists and cognitive neuroscientists have realized that many of the tests that we use, the cognitive and memory test that we use to try and detect Alzheimer’s disease aren’t picking up on this condition as early as we would like. So there’s been a lot of interest recently in trying to approach this problem in a different way, to ask if we might be able to identify new ways of testing learning and memory that might be more sensitive to these earliest brain changes. That is what ultimately motivated us and we approach this problem by asking whether a particular type of memory, when we engage in this type of memory, we mentally sort of travel back in time. Place ourselves at the scene of life events that happened recently or sometimes very remote in our past. And we almost start to reconstruct these events like they originally happened and watch them unfold in our minds eye. This type of memory is autobiographical memory. What’s interesting about it is it’s not trivial for the brain to allow us to do this. It relies on a number of regions to be coordinated and to work together to allow us to reconstruct these memories in our minds eye. And what’s important is that many of these brain regions are sensitive to some of the earliest brain changes of Alzheimer’s disease. So we thought this was an opportunity to see whether this type of memory might be sensitive to risk for developing Alzheimer’s disease. We tested individuals who would be classified as cognitively normal if they were to be seen by a neuropsychologist or neurologist and have an evaluation done. And we focused on recruiting two groups of individuals. All middle aged and older adults; individuals in their fifties, sixties, seventies or eighties. Half of these individuals were at increased risk for Alzheimer’s disease because of a particular gene that they carried, and the other half weren’t carriers of this gene and so they weren’t at increased risk for this reason. We used this basic model to allow us to see when we asked individuals to sort of mentally travel back in time in their minds eye and to try to relive life events as they shared them with us would we be able to detect the individuals who are at increased risk, who seemed to be having a harder time providing details that really add to the uniqueness of these memories. That make them vivid, that show how they were emotional. So that’s what we did in the study. We were recording these memories as they shared them, later we would go and score them for the types of details that they provided. And ultimately we did find that as a group, the individuals who were at increased genetic risk for Alzheimer’s disease generated these autobiographical memories with fewer specific details. Details that really captured the uniqueness of these life events. If you were to hear them in conversation I don’t know if you’d be able to notice in reality if it was a subtle deficient or disruption that could really be best captured through sort of careful scoring in a lab environment. But that’s what we found.
Is it a little bit subjective then or was there a specific and pretty strict guideline?
Dr. Grilli: There are specific and strict guidelines. This is a type of test and scoring procedure that actually has been used in neuropsychology and cognitive neuroscience research for almost two decades now. But it hadn’t been applied previously to this population to see if it was potentially sensitive to early signs of Alzheimer’s disease, in this context Alzheimer’s disease risk.
So was it a hundred percent, like everybody with this gene or not a hundred percent?
Dr. Grilli: No it wasn’t. As a group the individuals who were at increased risk were generating memories that were less detailed on the average. Some individuals in that group were generating memories that were very vivid, very elaborative but many of them weren’t. So that’s sort of an important point of this study is it doesn’t tell us sort of which ones for sure are at increased risk who might be in the earliest stages of Alzheimer’s disease. But it does tell us that this type of memory testing has promise as a new way of trying to pick up on early signs of Alzheimer’s disease.
So with this information did you give the details to the participants as well?
Dr. Grilli: We do at the end of studies provide summaries of what we’ve done and what we found. But our participants don’t know if they’re at increased genetic risk for Alzheimer’s disease, at least they don’t learn that from us. And because the tests are experimental we can’t at the end say, well this individual didn’t do particularly well and so we think this might mean that you have Alzheimer’s disease. It’s really not at that stage.
But eventually with this information if further studies prove to be conclusive like this what do you do with that information.
Dr. Grilli: Yeah there’s the possibility that at some stage down the line that autobiographical memory testing could be one of the tests that a neuropsychologist or a neurologist or a physician has in their clinic, in there tool box. And they could pull that test out and use it to assess whether they think somebody, whether their memory complaints might be a sign of normal aging or if think they might be an indication of something more serious. That sort of test could then prompt additional procedures and tests that could help close in on a diagnosis.
One thing that our Alzheimer’s patient that we interviewed that her partner loved was that it was noninvasive, non-expensive and potentially easy. It seems like it’s a good road to go down.
Dr. Grilli: Yes I think an advantage of cognitive testing, of neuropsychological testing in general is that it’s not expensive and not invasive. It will always be one piece of the puzzle; I don’t see a future where we only use neuropsychological testing to diagnose Alzheimer’s disease. But it can be an efficient way to begin that process or to determine that further testing isn’t necessary at this time.
Will you follow these people?
Dr. Grilli: We do want to. Our hope is to re-visit many of these individuals in a year or two and to evaluate where they are then. Where those individuals who were having a particularly difficult time retrieving autobiographical memories are; are they still in a category that we would call cognitively normal or have some of them begun to show more serious signs of decline that would justify a diagnosis of clinical impairment even if it’s mild. And so that’s something yes, that we hope to do in the next few years.
What’s next after the study, did you just publish?
Dr. Grilli: We did. The first wave of memory testing was just published. And we’ve already done additional follow up work with this new way of approaching memory testing for Alzheimer’s risk. In a separate study we’ve done another wave of autobiographical memory testing while also getting brain scans. There we’ll be looking to see if individuals who are having a difficult time retrieving autobiographical memories in a detailed way have signs of disruption or alteration in areas that we know were at increased risk of vulnerability for Alzheimer’s disease. And that will help us continue to build evidence for the utility of this test.
Is that study still going on?
Dr. Grilli: It is, yeah.
What else haven’t I asked you that you think is important to get in the study?
Dr. Grilli: I think you hit the highlights.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Jean Spinelli
520-626-2531
Sign up for a free weekly e-mail on Medical Breakthroughs called First to Know by clicking here.
