0:00

Let's have a look at an 82-year-old who is

0:03

severely Parkinsonian,

0:05

but also has severe dementia.

0:08

I don't have the information as to how long this

0:11

has been going on or which process has dominated.

0:15

However,

0:16

the degree of atrophy as we scroll

0:18

up and down is profound.

0:20

Now, atrophy does occur

0:22

at the end stage of Parkinson's disease.

0:24

So unless you have a time course,

0:26

it makes it difficult.

0:27

But with such profound atrophy,

0:30

you would at least have to consider the diagnosis

0:33

of Lewy Body Disease as a cause of a Parkinsonian

0:37

syndrome rather than classic isolated

0:40

Parkinson's disease.

0:41

There's quite a bit of overlap between the two.

0:44

Let's blow up the brain a little bit so we can

0:47

get a better feel for the arrangement of the

0:50

substantia nigra, which is cut off laterally

0:52

as you would see with classic PD.

0:55

And there is bleeding between the substantia

0:59

nigra and the red nucleus.

1:00

There's not a good crisp, linear, high signal,

1:04

compacta zone, yet the atrophy is profound.

1:08

So let's scroll up and down.

1:10

You should also be struck in this 82-year-old by

1:14

the relative paucity of vascular disease, which

1:17

wouldn't be a very good explanation for the

1:19

patient's clinical symptoms of dementia and

1:23

Parkinsonian-like symptoms, including tremor.

1:26

So the differential lies between Lewy Body Dementia

1:29

and Parkinson's disease.

1:31

This patient has proven, unfortunately,

1:34

at post LBD.

1:35

And one of the tip-offs to the diagnosis is

1:38

the involvement of the temporal lobe.

1:40

Now, it is said in the literature that temporal lobe

1:44

involvement is more severe step by step

1:48

or in other words, time versus time,

1:50

five years of Parkinson's disease

1:52

versus five years of LBD.

1:55

More atrophy in the entorhinal cortex in ALZ.

1:59

But compared with Parkinson's disease,

2:02

Lewy Body Dementia has more atrophy in the

2:05

entorhinal cortex and temporal lobe compared with PD.

2:09

So for temporal lobe involvement,

2:11

it goes ALZ, LBD, PD, in that order.

2:16

This patient has what I would call moderate

2:19

to severe temporal lobe atrophy.

2:22

So let's talk about Lewy Body Dementia,

2:24

which was described by Frederic Lewy in 1912.

2:28

These patients have spherical neuronal inclusions

2:33

that are intracellular.

2:35

And in fact,

2:35

they're intracytoplasmic staining

2:38

with ubiquitous antibodies.

2:40

Whereas PD patients have extraneural inclusions,

2:44

interstitial inclusions that include

2:47

Lewy body-like lesions as well.

2:49

So they both have Lewy bodies.

2:51

One is intracellular, the other is extracellular.

2:55

The Lewy Bodies and Lewy Body Dementia

2:58

contain neurofilament proteins

3:00

and ubiquitin proteins,

3:01

and it accounts for 15% of all dementias.

3:05

Some say that it's the second most

3:07

common dementia after ALZ,

3:09

although others might argue that frontal

3:12

lobar dementia is slightly more common.

3:15

The posterior cingulum tends to be preserved

3:18

especially on specked in LBD,

3:21

whereas the Myoinositol or Mi peak in spec is

3:26

elevated in ALZ.

3:29

Not so much in Lewy body disease.

3:32

A couple of final take-home points.

3:35

Clearly, there is imaging overlap between PD,

3:38

Parkinson's Disease and dementia with Lewy bodies.

3:43

They both get dementia,

3:45

but in Parkinson's disease,

3:47

motor symptoms predate cognitive symptoms

3:50

most of the time, in fact,

3:51

more than 90% of the time by approximately

3:54

twelve months.

3:55

Another differentiating feature

3:57

that you could use PET for,

3:59

especially amyloid staining PET,

4:02

is that beta amyloid is found

4:05

in dementia with Lewy bodies,

4:07

but not in classic Parkinson's disease.

4:10

In Alzheimer's disease,

4:11

and in Lewy Body dementia,

4:13

they both may have amyloid uptake on PET scanning

4:17

using agents like the Pittsburgh agent and others.

4:21

So in summary,

4:22

cognitive decline early on,

4:25

favor DLB,

4:27

cognitive decline 12 months or more later,

4:30

favor Parkinson's disease,

4:33

amyloid staining favors dementia

4:36

with Lewy bodies or ALZ

4:38

over Parkinson's disease.