17th June 2009 - New research
COMPARISON OF SCANNING METHODS FOR DIAGNOSING PARKINSON'S DISEASE
European journal of nuclear medicine and molecular imaging [2009] 36 (3) : 
454-462 (Eshuis SA, Jager PL, Maguire RP, Jonkman S, Dierckx RA, Leenders 
KL.) Complete abstract

Around 25% of people with Parkinson's Disease are wrongly diagnosed, due to 
the diversity of symptoms and the coincidence with other medical disorders. 
There are two methods of scanning the brain that enable the diagnosis of 
Parkinson's Disease by measuring the activity of dopamine in the brain : the 
SPECT scan and the PET scan. The aim of this study was to determine and 
compare the sensitivity and specificity of the two methods in the diagnosis 
of Parkinson's Disease. The patients underwent both types of brain scan. The 
SPECT scan and the PET scan were both able to distinguish people with 
Parkinson's Disease. For the early phases of Parkinson's Disease, 
sensitivity and specificity was 100%. When only one part of the brain was 
assessed, the accuracy was still 100% for the SPECT scan, but was 90% for 
the PET scan. This level of efficacy presently makes scanning, especially 
the SPECT scan, the most reliable method of diagnosing Parkinson's Disease. 
In order to refer to this article on its own click here.

14th June 2009 - New research
MEMANTINE FOR PARKINSON'S DISEASE DEMENTIA
Lancet Neurology [2009] Jun 9 [Epub ahead of print] (Aarsland D, Ballard C, 
Walker Z, Bostrom F, Alves G, Kossakowski K, Leroi I, Pozo-Rodriguez F, 
Minthon L, Londos E.) Complete abstract

The biochemistry of Dementia is completely distinct from that of Parkinson's 
Disease. However, dementia often occurs alongside Parkinson's Disease. 
Researchers tested the safety and efficacy of Memantine (an N-methyl 
D-aspartate [NMDA] receptor antagonist) in people with Parkinson's Disease 
Dementia. The primary measure of efficacy was clinical global impression of 
change (CGIC), which is not a precise measure of symptoms. It was concluded 
that "Patients with Parkinson's Disease Dementia might benefit from 
treatment with memantine, which was well tolerated" but that "Large-scale 
studies are now required to confirm" the preliminary findings. However, 
nearly a quarter of the participants did not complete the study due to 
adverse events, the difference in scores between those people taking 
Memantine and those taking a placebo was very marginal, there were no 
significant differences between the groups in secondary measures, and no 
comparison was made of the side effects caused by taking Memantine. In order 
to refer to this article on its own click here.

12th June 2009 - New research
PARKINSON'S DISEASE CAUSES THINNING OF THE RETINA
Archives of Ophthalmology [2009] 127 (6) : 737-741 (Hajee ME, March WF, 
Lazzaro DR, Wolintz AH, Shrier EM, Glazman S, Bodis-Wollner IG.) Complete 
abstract
People with Parkinson's Disease have been found to suffer a thinning of the 
retina. The retina is a light sensitive tissue lining the inner surface of 
the eye that is essential for vision. For more information about the retina 
go to Retina. A study quantified the thickness of the retina in people with 
Parkinson's Disease. No difference was found in the thickness of the outer 
retinal layer in Parkinson's Disease, when compared to people of the same 
age that don't have Parkinson's Disease. However, the thickness of the inner 
layer of the retina was found to be significantly reduced in Parkinson's 
Disease. This lessening of the retina could affect eyesight as Parkinson's 
Disease progresses. This effect on the retina may be because dopamine, whose 
deficiency causes Parkinson's Disease, besides being produced in the brain, 
is also produced in the retina, and so is liable to cause deficiency 
symptoms there as well. In order to refer to this article on its own click 
here.

11th June 2009 - New research
THE PREVALENCE OF GENETIC PARKINSON'S DISEASE
Annals of Human Genetics [2009] May 21 [ahead of print] (Paisán-Ruiz C, 
Washecka N, Nath P, Singleton AB, Corder EH.) Complete abstract

There are a number of genetic forms of Parkinson's Disease that can incline 
somebody towards Parkinson's Disease rather than inevitably cause it. It has 
previously been assumed that the number of people with Parkinson's Disease 
that are genetically inclined towards developing symptoms in this way was 
relatively small. However, researchers have found that just one of these 
genetic forms of Parkinson's Disease occurs in a third of people with 
Parkinson's Disease. Given that there are other genes that can incline 
somebody towards Parkinson's Disease means that the number of people 
genetically inclined towards Parkinson's Disease is far more than previously 
thought. The gene is called LRRK2 (leucine risk repeat kinase 2), which 
produces a protein called dardarin, a word derived from the Basque word 
dardara, meaning tremor. Mutations in LRRK2 are a common cause of familial 
Parkinson's disease. A combination of four gene variants are found in a 
third of people with Parkinson's Disease, but they are infrequent in the 
general population. This advance is expected to enable the identification of 
people at the greatest risk of Parkinson's Disease before symptoms arise. In 
order to refer to this article on its own click here.

6th June 2009 - New review
THE MYTH OF MASSIVE CELL LOSS IN PARKINSON'S DISEASE
It is widely claimed that there is a massive loss of the cells involved in 
Parkinson's Disease (the dopaminergic neurons), and that the loss of these 
cells is responsible for causing Parkinson's Disease. However, not a single 
study has ever shown this. This false assumption came about during the 
1990's after researchers carried out autopsy studies on people that had 
Parkinson's Disease. They mistakenly claimed that they had found a 
considerable loss of the cells that produce dopamine. However, their methods 
did not even measure cell loss. They measured cell activity instead. Their 
results and methods of those of others have shown that, in Parkinson's 
Disease, there is a large reduction in the activity of the dopaminergic 
neurons rather than a loss of them - down to about 20%-25% in mild 
Parkinson's Disease, and down to 5%-10% in severe Parkinson's Disease. There 
have been subsequent claims of massive cell loss in Parkinson's Disease. 
However, those claims have also been based on methods, such as the f-Dopa 
PET scan, that only measure cell activity rather than actual cell loss. 
Failure to properly scrutinise these studies has enabled the myth of massive 
cell loss in Parkinson's Disease to persist and become a widely prevalent 
assumption - even though not a single study has ever shown it to be true. 
In order to refer to this article on its own click here.

Rayilyn Brown
Director AZNPF
Arizona Chapter National Parkinson Foundation
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