Phase 4
N=19
Vigor and the LDR in Parkinson Disease
Parkinson Disease
Bottom Line
View on ClinicalTrials.gov: NCT04821830 ↗Enrolled (actual)
19
Serious AEs
0.0%
Results posted
Jul 2025
Primary outcome: Primary: Tapping Speed Task - Experiment 1 — 110.52; 128.89; 138.43; 145.86 taps/min
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 4
- Interventions
- carbidopa/levodopa, as prescribed by treating physician (Drug)
- Age
- Adult, Older Adult · 45+ yrs
- Sex
- All
- Sponsor
- University of Michigan
- Primary completion
- Apr 2024
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Tapping Speed Task - Experiment 1 |
110.52; 128.89; 138.43; 145.86 | — |
| PRIMARY Value Driven Attentional Oculomotor Capture Task - Experiment 2 - No Distractor Value |
1.14; 1.057; 1.03; 1.04 | — |
| PRIMARY Value Driven Attentional Oculomotor Capture Task - Experiment 2 - Low Distractor Value |
0.97; 1.15; 1.06; 1.03; 1.04 | — |
| PRIMARY Value Driven Attentional Oculomotor Capture Task - Experiment 2 - High Distractor Value |
0.97; 1.12; 1.05; 1.03; 1.04 | — |
| PRIMARY Joystick Movement Task - Experiment 1 - Low Incentive |
0.24; 0.20; 0.20; 0.19 | — |
| PRIMARY Joystick Movement Task - Experiment 1 - Medium Incentive |
0.24; 0.20; 0.21; 0.19 | — |
| PRIMARY Joystick Movement Task - Experiment 1 - High Incentive |
0.25; 0.20; 0.20; 0.18 | — |
| PRIMARY Grip Force Task - Experiment 1 - Low Incentive |
0.14; 0.14; 0.13; 0.12 | — |
| PRIMARY Grip Force Task - Experiment 1 - Medium Incentive |
0.14; 0.14; 0.12; 0.12 | — |
| PRIMARY Grip Force Task - Experiment 1 - High Incentive |
0.14; 0.13; 0.12; 0.12 | — |
| PRIMARY MDS-Unified Parkinson's Disease Rating Scale (MDS-UPDRS): Part III - Experiment 1 |
31.45; 24.36; 18.64; 14.82 | — |
Summary
Parkinson disease (PD) is a common disorder in which reduced speed of movement results from inadequate brain production of the chemical dopamine. The most effective treatment for PD is the drug levo-dopa, which partially replaces brain dopamine. Despite decades of successful use, how levo-dopa improves speed of movement in PD is not understood. This observational study recruits participants who have been prescribed levo-dopa by their treating physicians. Before their first dose, immediately after their first dose and later, when their dose has been stabilized, they will engage with the research team to participate in a few simple experiments to measure speed, grip strength, tremor, and stability (on and off of treatment). The purpose of these experiments is to understand how levo-dopa treatment in Parkinson disease enhances movement speed. An important but not understood component of levo-dopa action, the Long Duration Response (LDR), lasts for days to weeks. A basic function of dopamine signaling in the brain is modulation of motivation - the coupling between effort and action values. These experiments will determine if the LDR is associated with relative normalization of motivation function in the brain. The motivation behavior of recently diagnosed PD participants will be examined before and after treatment with levo-dopa to determine if the magnitude of the LDR is correlated with improvements in motivation behavior.
Eligibility Criteria
Inclusion Criteria
- Diagnosis of Parkinson Disease
- Previously Untreated or treated for 11
- Use of dopamine agonists or stimulants
- Evidence of a stroke or mass lesion on prior structural brain imaging (MRI or CT)
- Evidence of any confounding medical or psychiatric problem that would preclude task participation.
- Participants with cognitive impairment that might impair their capacity to provide informed consent.
Data sourced from ClinicalTrials.gov (NCT04821830). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.