How to Make an Early Diagnosis

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Dr. Agronin:
This is CME on ReachMD, and I'm Dr. Marc Agronin. I'm here with my colleague Dr. Richard Isaacson.

So let's dive right in and talk about early diagnosis of Alzheimer's disease. How do we do it? What challenges or barriers might get in the way? And, Dr. Isaacson, I guess I pose it this way: What's the one really critical question that either a caregiver or a person themselves or their physician needs to be asking if there's a concern about cognitive impairment? And if so, then what do we do to try to get at that early diagnosis?

Dr. Isaacson:
Yeah, so I think in the future where there's going to be a simple blood test, or a simple cognitive test, or a simple test, or a simple something that can deduce this in a much more easier and more effective way. But right now, there's a variety of different tools that we can do. And I think if I had to choose one thing it's to take a detailed clinical history. How is that person doing over the last several months, several years? And how has that change been from their original baseline?

If there's been a change in their ability to recall information and a problem with short-term memory loss that’s been progressive over time, that clinical history, those details really suggest that something could be happening in terms of pathologic decline in the brain. And common things happen commonly; the most common cause of neurodegenerative dementia and short-term memory loss is Alzheimer's disease. And these are things that will allow us to at least say, hmm, maybe we need to think about doing more tests.

So that alone isn't going to be perfect, but we're going to do a physical exam. We, of course, need to do some screening cognitive tests. I wish there was a perfect test. I think a lot of people use the Mini-Mental status exam. It's helpful because everyone's familiar with it, but it's an imperfect test. I do think the MoCA, Montreal Cognitive Assessment, is also an option. And there's other more extensive neurocognitive testing that can help. And then of course, there's Alzheimer's biomarkers; there's brain imaging; there's all sorts of different studies.

But I think when it takes just a few minutes, just talk to the patient, talk to your loved one, and try to understand where were they at baseline? Where have they gone? And what were the exact specific symptoms, the exact changes that the person has observed over time.

Dr. Agronin:
Yeah, without question that has to be the mainstay of the treatment. When it comes to neuroimaging, if obviously, we want to be comprehensive, but what's the first priority there in terms of the type of scan and what you would look for on a scan?

Dr. Isaacson:
Yeah, so, aside from doing the usual screening blood tests, the thyroid check and the B12, and a lot of times, you may find something with the thyroid or the B12, but that's not necessarily going to be the cause of the cognitive decline, but it's always important to rule out. We have to do some sort of brain imaging tests. The American Academy of Neurology guidelines state that we have to do something, whether it's a CAT scan or an MRI. In my clinical experience and in my practice, we always, of course, choose an MRI of the brain. We do thin cuts, thin slices or coronal cuts, through the temporal lobes to actually evaluate is there shrinkage of the memory center, the atrophy of the hippocampus. And if you have that biomarker on a read and you have progressive short-term memory loss, that person could certainly have the earliest stages of Alzheimer's disease.

But in terms of neuroimaging, we can now do biomarkers between an amyloid scan using a PET scan or a tau scan, also using a PET scan. However, these tests are expensive; they have radiation; they're costly. You could do a spinal tap. A spinal tap is something that not everyone is excited about doing. There also is a cost to that, and a procedural cost and time, but that looks for both amyloid and tau in the spinal fluid.

But where I'm really excited about is the emerging area of blood-based biomarkers. And nowadays in the United States in 49 states, we can get the amyloid blood test today. And coming very soon is both an amyloid and tau blood test that has a very good sensitivity and specificity for someone having amyloid in the brain based on a PET scan. So I think this whole era of early diagnosis is going to change quite rapidly as we have this new era of blood-based biomarkers.

Dr. Agronin:
I would say this is a key takeaway here. Don't rush to judgment. Just because someone is getting older doesn't mean that automatically they have memory problems. If someone has memory problems, that doesn't automatically mean that they have Alzheimer's disease. The bottom line is that you need this comprehensive evaluation, all the different parts put together. And then critically, you need expert eyes to look at the information to put it together, to synthesize, to take the story over time, and to try to determine what's the best diagnosis.

So, Dr. Isaacson, again, this has been a great bite-sized discussion. Our time is up here. But, everyone, thank you for listening.

Dr. Isaacson:
Thanks so much.

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