Vascular Cognitive Impairment With Dr. Lisa C. Silbert

Vascular cognitive impairment is a common and often underrecognized contributor to cognitive impairment in older individuals, with heterogeneous etiologies requiring individualized treatment strategies. 

In this episode, Katie Grouse, MD, FAAN speaks with Lisa C. Silbert, MD, MCR, FAAN, an author of the article “Vascular Cognitive Impairment,” in the Continuum December 2024 Dementia issue.

Dr. Grouse is a Continuum® Audio interviewer and a clinical assistant professor at the University of California San Francisco in San Francisco, California.

Dr. Silbert is is co-director at Oregon Alzheimer's Disease Research Center, a Gibbs Family Endowed professor of neurology, a professor of neurology at Oregon Health & Science University, a staff neurologist, director of Cognitive Care Clinic, and director of the Geriatric Neurology Fellowship Program at Portland Veterans Affairs Health Care System in Portland, Oregon.

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Read the article: Vascular Cognitive Impairment

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Full transcript available here

Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum, the premier topic-based neurology clinical review and CME journal from the American Academy of Neurology. Thank you for joining us on Continuum Audio, which features conversations with Continuum's guest editors and authors who are the leading experts in their fields. Subscribers to the Continuum Journal can read the full article or listen to verbatim recordings of the article and have access to exclusive interviews not featured on the podcast. Please visit the link in the episode notes for more information on the article, subscribing to the journal, and how to get CME.

Dr Grouse: This is Dr Katie Grouse. Today I'm interviewing Dr Lisa Silbert about her article on vascular cognitive impairment, which is part of the December 2024 Continuum issue on dementia. Welcome to the podcast and please introduce yourself to our audience. 

Dr Silbert: Hi Katie. Thanks for having me here today. Like you mentioned, my name is Lisa Silbert. I am a behavioral neurologist at Oregon Health and Science University and my research focus is in the area of vascular contributions to cognitive impairment and dementia.

Dr Grouse: It's such a pleasure to have you and I really enjoyed reading your article. Just incredibly relevant, I think, to most practicing general neurologists, and really to any subspecialty. I'd like to start by asking, what do you think is the main takeaway point of your article for our listeners? 

Dr Silbert: Yeah. I think, you know, the field of vascular cognitive impairment has changed and evolved over the last several decades. And I would say the main take-home message is that vascular cognitive impairment or vascular dementia is no longer a diagnosis that is only considered in someone who's had acute decline following a clinical stroke. That we have to expand our awareness of vascular contributions to cognitive impairment and consider other forms of the disease that can cause a more subacute or slowly progressive form of cognitive impairment. And there are many, many forms of vascular cognitive impairment that present in a more slowly progressive manner. The other thing I would say as a major take-home message is that we know that cerebrovascular disease is a very common copathology with other forms of dementia and that it lowers one 's threshold for manifesting cognitive impairment in the context of multiple pathologies. And so, in this way, vascular cognitive impairment should be considered as a contributing and potentially modifiable factor in any dementia. 

Dr Grouse: I found that last point just really, really fascinating. And also, you know, the reminder that a combination of pathologies are more common than any one. To your initial point, I'm actually curious, could you kind of outline for us how you approach diagnosing vascular cognitive impairment? 

Dr Silbert: Yeah. So with everything in neurology, a lot of it comes down to the initial history taking. And so part of the work up always includes a very detailed history of the presentation of cognitive impairment. Any time there is an acute change in cognition, vascular contribution should be considered, particularly if it's in the context of a clinical stroke or some kind of event that might have lowered cerebral blood flow to the brain. And then having said that, I already mentioned there are many forms of vascular cognitive impairment that can mimic neurodegenerative disease in terms of its course. So being more slowly progressive. And so because of that neuroimaging, and in particular MRI, has become an extremely valuable tool in the workup of anyone who presents with cognitive impairment in order to evaluate contributions from cerebral vascular disease. And so, MRI is a really helpful tool when it comes to teasing out what may be contributing to a patient's clinical syndrome, as well as their other comorbid medical issues, including stroke risk factors and other kind of medical conditions that might contribute to reduce cerebral blood flow.

Dr Grouse: I'd love to talk a little bit more about that. You know, as is often the case with neurologic disease associated with vascular pathology, the importance of prevention, you know, focusing on prevention of vascular diseases is so important. What are some things that we can make sure to focus on with our patients and, you know, particularly anything new to be aware of in counseling them?

Dr Silbert: Yeah, I'm really glad you asked me that question because like I mentioned, you know, cerebral vascular disease is so common, it lowers one's threshold for cognitive impairment in the face of other age-related brain pathologies. And so, it's really important for all of us to focus on preserving our cognitive health, even starting in midlife. And so, there are a number of areas that I counsel my patients on when it comes to preserving cerebral health and maximizing cerebrovascular health. And so, these stem from the American Heart Association's Life's Essential 8 because we know that preserving cardiovascular health is likely going to also preserve cerebral vascular health. And so, some of the things that I'm very commonly discussing with my patients are controlling stroke risk factors such as blood pressure, blood sugars and cholesterol, maintaining a healthy weight, and then also working towards a lifestyle that includes a healthy diet, no smoking, regular exercise. And then new within the last couple years is also the recommendation that people get adequate sleep, which is something that hasn't been focused on previously.

Dr Grouse: I was really interested in reading your article to learn about enlarged perivascular spaces and the role as a mediating factor in the interaction between through a vascular dysfunction and development and progression of neurodegenerative pathology. Can you elaborate on this further?

Dr Silbert: So, this is an area that's still largely unknown in the field, and it's an area where there's a lot of emerging work being done. The short answer is, we really don't know with great certainty how it directly connects with accumulating Alzheimer's pathology. But there is some evidence to suggest that the perivascular space is involved in the clearance of toxic solutes from the brain, including Alzheimer's disease pathology. And so there's a lot of work looking at how potentially cerebrovascular risk factors might affect the clearance of those toxic solutes through the perivascular space, including pulse pressure changes that might occur with accumulating cerebrovascular disease and other potential contributors. But one thing I can say with more certainty is that the, you know, location of perivascular spaces is thought to help distinguish those who might have cognitive symptoms due to cerebrovascular disease versus due to cerebral amyloid angiopathy. Or I guess I should say location is helpful in terms of recognizing vascular contributions to cognitive impairment that's due to arteriolosclerosis versus that due to cerebral amyloid angiopathy. In so much that… when we see a lot of perivascular spaces in the basal ganglia in the subcortical structures, that is thought to be more associated with arteriolosclerosis and hypertension type related vascular cognitive impairment. Whereas when we see multiple perivascular spaces within the centrum semiovale, that tends to be more associated with cerebral amyloid angiopathy.

Dr Grouse: That's so interesting. And on the topic ofcerebral amyloid angiopathy, you did go into this a good deal. And you know, I think I encourage everybody to revisit the article to remind themselves about, you know, the findings that can increase the suspicion of tribal amyloid angiopathy. However, you also talked about transient focal neurologic episodes, which I th