Have you ever wondered what impaired really means in dementia testing?

Like how does the neuropsychologists know what is impaired?

That's what we're covering in today's video.

When someone gets a formal dementia evaluation, they take many different

tests, and the neuropsychologist looks at those test scores in the individual tests,

and they pretty much come to a conclusion.

Is this considered a normal?

A below average performance, a high average performance,

maybe an impaired performance.

So what they do is they look at the specific score your loved one got on a

test, and then they compare that score.

To what the general population would typically score on that same test.

So they're looking to see how much does your loved one's test

score deviate from the average.

This is called a standard.

Deviation.

It's how far a score deviates from a certain group of people.

So when they're looking at test scores, they're looking

at a bell curve inside here.

That's the average range.

So this is 50% of people would perform in this area.

That's considered average.

Anything considered one standard deviation below the.

Or one standard deviation above the mean is still considered

generally within normal limits.

It's once the person's score starts to deviate beyond one standard deviation,

are there major concerns happening?

. If somebody scores two standard deviations below the mean, that's

impaired, that means that the person's score is lower than about

98% of the scores in that population.

And then if somebody is 1.5 standard deviations below the mean, so

they're not quite at two standard deviations, they're not quite

impaired, but they're beyond the.

about 1.5.

We consider that borderline impaired.

It's a little bit of a gray area, so in neuropsych testing, the

provider is looking at the scores and looking to see how far it deviates

and they're viewing that score.

This is their frame of reference to see how well the person is doing.

And so a lot of times, I remember when I used.

To be giving these tests in the clinic sometimes, understandably so the patient

might say something like, nobody would do good on this, or Who could ever get these?

Right.

And it's a little bit like, well, we have a reference point.

We actually have a database, a group of people have gone through these

tests and they've all taken them.

And so we're able to see.

How do people without any cognitive impairment, how do

those people generally perform?

So we get a read, we get an idea of what is considered normal in baseline for the

general population, and then we would take a look at, well, how did this person

do compare to the general population?

So all of the tests that are given to your loved one with dementia,

they have all been standardized.

To a group of people and a group of people.

Usually people without any conditions at all take these tests so that we

have a reference point of how the majority of people should perform.

And each test has its own database, if you will.

Each test has been given to a group of people to take it so we

can get a sense of what is normal.

We call this normative.

What are the norms?

So like if I were to get a test of somebody, I would say, let me go see

what the norms are so I can see how far this person deviates from the norm.

So after your loved one goes through all of their different tests, the

neuropsychologist takes that information and compares each of those test

scores to the normative data that they have on those particular tests.

And when someone is two standard deviations below the mean on one of

those, It's very important for that neuropsychologist to try to figure

out what is causing that impairment.

It could be dementia, it could also be something else, and we would have to

rule out any other possibility for why that person did so poorly on that test.

For example, if somebody had hearing impairment, And they weren't wearing

their hearing aids and they took a verbal memory test where they had to remember a

list of words and they performed impaired.

We probably would take that with a grain of salt because they may not have even

been able to fully hear the words, so we're not actually testing their memory.

that was more of a hearing test, so this is why it's so important.

You can't just look at a score to determine what that means.

We have to look at the big picture.

Another common thing is somebody might go through a whole series of

tests and be impaired on multiple different areas, but they might also

be significantly depressed, and people who are significantly depressed.

Perform poorly on a lot of the same tests that we would

give for people with dementia.

And so in those situations, we would want to do what we can to treat the

depression and then have them return for testing to see if the scores have changed.

So when someone is impaired on dementia testing, it basically means they are

impaired compared to a group of people who have already been through that

test and have been considered normal.

And this is where it gets even more tricky and important is that there are.

Normative groups.

Obviously somebody who's 23 is going to perform differently than somebody who is

83 on a time task of processing speed.

The person who is 83 is understandably and normally going to be slower

than the person who is 23, so we would not compare the 83 year old's.

To a 23 year old's performance.

Each of these tests have the normative data for that group of people.

So if I took the score on how the 83 year old performed and I looked

at the database of 23 year olds, I'm probably gonna say this, 83 year old's

impaired, but I would never do that.

Nobody would ever do that.

If you know what you're doing, what you do is you take the 83 year old's test score

and you compare it to other people of a similar age, then you would be able to d.

Is this within the normal range or do we have a concern here?

Again, another reason why a simple number does not tell you much about

how that person's brain is doing.

You have to consider other factors and make sure you're looking

at the right reference points.

There are different normative data for gender, age, race, educational history,

and so the more details we have, the more we could compare how somebody

did to a group of people who are most similar to that person, the more dialed.

We'll have the results, the more faith we can have in the

results that we're getting.

For example, if we give a 68 year old who had a seventh grade education,

a certain test, and they performed in the low average range, right?

We would probably think that's pretty normal for them, but if another person the

same age took the same test and they were also in the low average, But they had 16

years of education and they were a high executive, a high ranking job, c e o, and

they performed in the low average range that would likely indicate a decline.

That would be more of a concern than the person who had seven years of education.

And so we would want to keep a closer eye on the person who

had the higher education level.

This likely is representing a decline from their previous level of functioning.

They were probably likely in the high average range.

So the fact that they're performing in the low average range could indicate

that this is the beginning of dementia.

Now, normative data is not.

Perfect.

There are definitely flaws in there.

We have limited normative data for people who are over the age of 85.

We have limited normative data for different ethnicity groups, different

racial groups, and so it's not perfect.

It definitely has flaws.

Most tests were normed on middle class Caucasian males,

but that's an introduction.

To what it means when your loved one sits through hours of

testing and how that person, that provider, the neuropsychologist,

comes up with the scores.

It's also why the neuropsychologist is probably one of the few disciplines

that when your loved one goes and sees, you're probably waiting weeks,

maybe even a month or more to get the.

Full results because the neuropsychologist job is almost just beginning after they

get the test scores, they're looking up the normative data and all these different

tests, putting together the big picture.

So it's not like a reading, like a blood test, you could just put

through a lab and get a reading back.

It's much more in-depth, and it definitely requires a trained special.

Person to be able to interpret them.

What dementia testing questions do you have?

Would you like any follow up on any of this?

Did you learn anything new?

Let me know what you think in the comments below.

I look forward to reading them.

I'll be back next week with a new video.

In the meantime, Careblazer, keep up the great work and you've.

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