http://www.eurekalert.org/pub_releas...-riw061411.php
""The best treatment option for managing the motor symptoms of Parkinson's disease remains dopamine replacement therapy. In some patients however, it can have a negative effect on specific aspects of cognition. Our discovery will therefore enable us to explore different medication and non-medication based avenues that could help improve the overall health of those affected. Our findings may contribute to helping develop personalized medicine - an avenue that is currently commanding a great deal of attention", exclaims Dr. MacDonald."

http://www.labmate-online.com/news/n...eatment/15643/" The part of the brain most affected by dopamine depletion as a result of Parkinson's disease is the striatum which is divided into several structures.

In Parkinson's disease, the dorsal striatum is more severely affected while the ventral striatum remains largely unaffected in the early stages.

"We observed that while dopamine replacement therapy enhances the functions of the dorsal striatum, it is at the expense of the ventral striatum which suffers a dopamine overdose, impairing its function", Dr Monchi explained."

i am under the impression that press releases are not copyrighted so i'm going to print the whole article here, it's very interesting - has anyone heard of this before? i experience it every day...we are helping our motor symtoms but impairing our cognition due to dopamine getting into both parts of the striatum- other part that is responsible for cognitive functions gets overdosed. So our meds are making us stupid. I can't talk at night or some days hardly at all, without stammering , very poor articulation and volume, and j ust sound like i'm drugged or drunk. which i am, with my own prescriptions.

thanks imad very enlightening for me.


Public release date: 15-Jun-2011
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Contact: William Raillant-Clark
w.raillant-clark@umontreal.ca
514-343-7593 begin_of_the_skype_highlighting 514-343-7593 end_of_the_skype_highlighting
University of Montreal

Researchers identify why dopamine replacement therapy has a paradoxical effect on cognition

This release is available in French.Dopamine replacement therapy, which is used to manage motor symptoms associated with Parkinson's disease, can, at times, adversely affect cognition. Dr. Oury Monchi, Ph. D. in neuronal modeling and Head of the Neurophysiological and Neuroimaging Research theme at the Centre de recherche de l'Institut universitaire de gériatrie de Montréal (IUGM), which is affiliated with the Université de Montréal, and Dr. Penny A. MacDonald, Neurologist and postdoctoral fellow in Dr. Monchi's laboratory, have identified the reasons why within the framework of a clinical study recently published in Brain: A Journal of Neurology. This marks the second time in three months that Brain has published the results of IUGM researchers.

"The aim of our study was to understand the effects of dopamine replacement therapy on various aspects of cognition in patients with Parkinson's disease. When it comes to this particular disease, the part of the brain most affected by dopamine depletion is the striatum which is divided into several structures.

In Parkinson's disease, the dorsal striatum is more severely affected than the ventral striatum, which remains relatively unaffected, at least during the first phases of the disease. We observed that while dopamine replacement therapy enhances the functions of the dorsal striatum, it is at the expense of the ventral striatum which suffers a dopamine overdose, impairing its function", states Dr. Monchi.

Until now, the effect of dopamine replacement therapy on cognition in individuals with Parkinson's disease was controversial. The purpose of this study however, was to further investigate. This led to a series of laboratory tests and neuroimaging studies that allowed researchers to clearly define the distinct cognitive functions performed by the dorsal and ventral striatum, thereby shedding some light on the issue.

"The best treatment option for managing the motor symptoms of Parkinson's disease remains dopamine replacement therapy. In some patients however, it can have a negative effect on specific aspects of cognition. Our discovery will therefore enable us to explore different medication and non-medication based avenues that could help improve the overall health of those affected. Our findings may contribute to helping develop personalized medicine - an avenue that is currently commanding a great deal of attention", exclaims Dr. MacDonald.


Summary of the Research
Twenty two Parkinson's disease patients without dementia and twenty two healthy individuals were included in the first part of the study (behavioural), while thirteen healthy young adults participated in the second part of the study (neuroimaging). Each participant was asked to repeatedly choose numbers (288 times) such as selecting the higher of two numbers, for example.

On some occasions, patients were given no reinforcement, while on other occasions, they were influenced by various cues that made it easier to answer (a function usually associated with the dorsal striatum), or more difficult to answer due to interference (associated with the ventral striatum). Parkinson's patients were tested on or off medication.

Selection was validated with functional magnetic resonance imaging which was used to observe cerebral activity during the exercises. Results demonstrated that while dopamine replacement enhances results for , conditions associated with interference (dorsal striatum), it reduces results for conditions associated with facilitation (ventral striatum).

Hi Paula, Have been told that at peak sinemet times (think 2 to 2 1/1 hrs after taking the L-dopa), the "extra" dopamine could spill over into the limbic system, activating the dopamine receptors within, resulting in behavioral, emotional and cognitive adverse effects. Primary reason for keeping sinemet dosage at minimum.

For me, 2 hrs after taking 100/25 sinemet, I experience kind of disabling short breath and speech problem. This could not be explained by my neuro who assured me that he has treated thousands of PD patients but never encountered similar complain.

The family doctor ruled out other causes for the problem.

Left alone to deal with it, I cut my dose of sinemet from 3 times 100/25 sinemet to half tablet and added maccuna tablets (providing about 240 dopamin, 3 times daily. I have been on this formula for some weeks and I seem to be okay!. But Pls. don't ask me why !

cheers
Imad