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Biomarkers for cognitive impairment in PD
This article is part of a "mini-symposium" in the journal "Brain Pathology" on the topic of "Dementia in Parkinson's Disease."
In the abstract, the authors indicate that clinical biomarkers are "urgently needed" to differentiate among PDD/DLB and AD, to predict dementia in Parkinson's Disease, and to "monitor responses of patients to new therapies." The article reviews where we stand in terms of developing biomarkers for cognitive impairment in PD.
From my reading of the article, it seems that the best we can do right now is to differentiate between:
* neurodegenerative dementias and non-neurodegenerative dementias using olfactory tests
* Lewy body diseases and Alzheimer's using 18F-fluorodopa PET and DAT SPECT studies
* Lewy body-related dementias and non-Lewy body-related dementias using cardiac MIBG
The olfactory test is probably inexpensive. Certainly 18F-fluorodopa PET, DAT SPECT, and cardiac MIBG are expensive tests that may not be covered by insurance and may only be available to research study participants at specialized medical facilities in the US.
Brain Pathology. 2010 May;20(3):660-71.
Biomarkers for cognitive impairment in Parkinson disease.
Shi M, Huber BR, Zhang J.
Department of Pathology, University of Washington School of Medicine, Seattle, Wa.
Cognitive impairment, including dementia, is commonly seen in those afflicted with Parkinson disease (PD), particularly at advanced disease stages. Pathologically, PD with dementia (PD-D) is most often associated with the presence of cortical Lewy bodies, as is the closely related dementia with Lewy bodies (DLB). Both PD-D and DLB are also frequently complicated by the presence of neurofibrillary tangles and amyloid plaques, features most often attributed to Alzheimer disease.
Biomarkers are urgently needed to differentiate among these disease processes and predict dementia in PD as well as monitor responses of patients to new therapies. A few clinical assessments, along with structural and functional neuroimaging, have been utilized in the last few years with some success in this area. Additionally, a number of other strategies have been employed to identify biochemical/molecular biomarkers associated with cognitive impairment and dementia in PD, e.g. targeted analysis of candidate proteins known to be important to PD pathogenesis and progression in cerebrospinal fluid or blood.
Finally, interesting results are emerging from preliminary studies with unbiased and high throughput genomic, proteomic and metabolomic techniques. The current findings and perspectives of applying these strategies and techniques are reviewed in this article, together with potential areas of advancement.
PubMed ID#: 20522092 (see pubmed.gov for this abstract only)