This abstract is quite understandable. (I don't have access to the full article; let me know if anyone else can get it at no charge.)

Here are the key sentences: "The concept of PDD and DLB being separate conditions is comparatively new, and the most promising tools with which to separate them at present are cerebrospinal fluid (CSF) markers and positron emission tomography (PET) scanning that indicate increased amyloid-beta burden in DLB compared to PDD. However as yet there are no markers that unequivocally distinguish between PDD and DLB."

I'm not sure I entirely understand the point of trying to distinguish between PDD and DLB. In the future, if we have some drugs to fight Alzheimer's Disease, then being able to distinguish between these two Lewy Body Dementias would be helpful (since DLB frequently co-occurs with AD).

Whether PDD and DLB are separate disorders is controversial. There's a famous Bay Area neurologist (PD expert) who insists that they are not separate disorders and wonders who granted McKeith, et al, the right to say they are. Some neurologists I know don't like the term "Lewy Body Dementia." So...the discussion continues.

Robin


Parkinsonism & Related Disorders. 2010 Mar 23. [Epub ahead of print]

Biomarkers: Parkinson disease with dementia and dementia with Lewy bodies.

Johansen KK, White LR, Sando SB, Aasly JO.
Department of Neuroscience, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Neurology, St Olav's Hospital, University Hospital of Trondheim, Norway.

Dementia is a common feature in Parkinson disease (PD), the time of onset determining how patients are classified. Those patients where dementia develops prior to parkinsonism or during the first year of disease are designated as having dementia with Lewy bodies (DLB). In those where dementia develops over a year after the onset of motor signs, the condition is known as Parkinson's disease with dementia (PDD).

While this seems at first sight to be a definitive way to distinguish these conditions, reality is rather different. The overlap between them is considerable, and there is much uncertainty associated with patients who have both motor symptoms and early cognitive impairment. The diagnosis is still based on medical history and clinical evaluation. It is not even certain that they can be accurately distinguished at autopsy.

For this reason, the data concerning these entities have been reviewed, to examine various markers employed or measured in clinical, neuropathological, neuroimaging, and biochemical investigations.

The concept of PDD and DLB being separate conditions is comparatively new, and the most promising tools with which to separate them at present are cerebrospinal fluid (CSF) markers and positron emission tomography (PET) scanning that indicate increased amyloid-beta burden in DLB compared to PDD. However as yet there are no markers that unequivocally distinguish between PDD and DLB.

PubMed ID#: 20338799

Robin, do you know if the medication caveats are the same in PDD & LBD [If, in fact, they are separate disorders]? I know that NMS can occur in PD as well as LBD with neuroleptics. Are there any differences in the pharmacological effects of other drugs? Thanks for sharing the abstract information.

The terminology is very confusing. The term "Lewy Body Dementia" (LBD) refers to BOTH Parkinson's Disease Dementia and Dementia with Lewy Bodies. So anything cautions you read on lbda.org apply to both types of Lewy Body Dementia.

And, as you know, many of the cautions about neuroleptics apply to the elderly or those with dementia. And there's a risk of NMS at any age, with or without dementia.