Dopamine Effect on Inhibitory Control

Summary

The effect of Levodopa medication on inhibitory control in Parkinson's patients is extremely debated despite the fact that this has potential clinical and therapeutic implications. A key confounding factor of many previous studies is that they did not take the disease duration in consideration. In fact, in moderate-to-advanced stages of Parkinson dopaminergic drugs could not produce a clear effect because too few dopaminergic cells for the drugs to operate on survived. Hence, in this study, we will compare the performance in the stop signal task in early-stage versus moderate-to-advanced stages Parkinson's patients both in ON and in OFF medication. In addition, to have a baseline measure of inhibitory control we will compare patient's performances with that of age-matched subjects.

Conditions

• Idiopathic Parkinson's Disease

Interventions

DRUG

PD patients H&Y=1.5-2 Medications ON

Parkinson's patients will be allowed to the first-morning dose of levodopa medicament (levodopa, dopamine agonists, anticholinergic drugs, or a combination of levodopa and an anticholinergic drug) which normally allowed the patient to attain the best control of symptoms one hour before being tested (19). Patients will perform both the stop-signal task and the go-only task. Experimental conditions will be counterbalanced across patients.

DRUG

PD patients H&Y=1.5-2 Medications OFF

Parkinson's patients will not take medications overnight prior to the study (20). Patients will perform both the stop-signal task and the go-only task. Experimental conditions will be counterbalanced across patients. This intervention will be given on a different day with respect to the Medication ON intervention. The order of intervention will be counterbalanced across subjects

BEHAVIORAL

Healthy age-matched controls

Healthy controls will perform the stop signal task and the go-only task in the same day. The order of administration will be counterbalanced.

DRUG

PD patients H&Y=3 Medications OFF

Parkinson's patients will not take medications overnight prior to the study (20). Patients will perform both the stop-signal task and the go-only task. Experimental conditions will be counterbalanced across patients. This intervention will be given on a different day with respect to the Medication ON intervention. The order of intervention will be counterbalanced across subjects

DRUG

PD patients H&Y=3 Medications ON

Parkinson's patients will be allowed to the first-morning dose of levodopa medicament (levodopa, dopamine agonists, anticholinergic drugs, or a combination of levodopa and an anticholinergic drug) which normally allowed the patient to attain the best control of symptoms one hour before being tested (19). Patients will perform both the stop-signal task and the go-only task. Experimental conditions will be counterbalanced across patients.

Sponsors & Collaborators

• Giovanni Mirabella

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

FACTORIAL

Eligibility

Min Age

40 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-09-30

Primary Completion

2023-01-20

Completion

2023-11-10

Countries

• Italy

Study Locations