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Rating L-DOPA-Induced Dyskinesias in the Unilaterally 6-OHDA-Lesioned Rat Model of Parkinson's Disease
Published on: October 4, 2021
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Dopa Responsiveness in Parkinson's Disease
Sacha E Gandhi1, Anahita Nodehi2, Michael A Lawton2
1School of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom.
Movement Disorders Clinical Practice
|June 20, 2024
Summary
Dopamine response patterns in Parkinson's disease (PD) evolve over time, with definite responses increasing with disease duration. Early treatment response may not be a reliable diagnostic indicator for PD.
Area of Science:
- Neuroscience
- Neurology
- Pharmacology
Background:
- Dopaminergic responsiveness is a hallmark of Parkinson's disease (PD).
- Understanding the temporal evolution of dopaminergic response in PD is crucial.
- Limited data exists on how dopaminergic responsiveness changes over the course of PD.
Purpose of the Study:
- To investigate the longitudinal patterns of dopaminergic responsiveness in Parkinson's disease.
- To identify distinct clusters of dopaminergic response over time.
- To determine factors that predict these identified response patterns.
Main Methods:
- Analysis of repeated dopaminergic challenge tests from the Parkinson's Progression Markers Initiative (PPMI).
- Growth-mixture modeling was employed to identify distinct longitudinal response trajectories.
- Multinomial logistic regression was used to identify predictors of these response clusters.
Main Results:
- A total of 1525 dopaminergic challenge tests from 336 PD patients were analyzed.
- The proportion of definite dopaminergic responses (≥24.5%) increased with longer disease duration (48.0% at 1-2 years to 74.3% later).
- Three distinct response groups were identified: Striking (8.7%), Excellent (32.7%), and Modest (58.6%), with varying clinical and cognitive characteristics.
Conclusions:
- Three distinct longitudinal patterns of dopaminergic response were observed in Parkinson's disease.
- The increasing prevalence of definite dopaminergic responsiveness over time suggests its utility as an early diagnostic marker may be limited.
- Clinical and cognitive factors differentiate the identified response groups, offering insights into disease heterogeneity.
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