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Master of Science


Physiology and Pharmacology


Dr. Mandar Jog


Parkinson’s disease (PD) is a neurogenerative movement disorder that often requires surgical interventions such as deep brain stimulation (DBS) when motor complications arise from long term levodopa therapy. Understanding the level of motor improvement received by patients from levodopa (levodopa response; LR) at each stage of disease duration is integral to optimizing both current treatment and DBS implementation. In this study, the levodopa challenge test was employed to investigate the LR in early to advanced stages of disease in 70 PD participants. The LR only moderately correlated with disease duration, suggesting large interindividual variability in the LR between patients of similar disease durations. The LR correlated most strongly with motor symptom severity in the OFF-medication state. We proposed that this was in part due to whether an individual relies more heavily on a nigral or extra-nigral control of dopamine in the PD brain. These findings offer support for implementing DBS in individuals earlier in disease and with smaller motor responses to levodopa.

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