Trial Review

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626000769381
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
9/06/2026
Date registered
Help: Date registered
26/06/2026
Date last updated
Help: Date last updated
26/06/2026
Date data sharing statement initially provided
Help: Data sharing statement date
26/06/2026
Type of registration
Help: Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of dopamine on learning and cognition
Scientific title
Effects of Acute Levodopa Administration on Learning and Cognition in Healthy Adults: A Randomised, Double-Blind, Placebo-Controlled Study
Additional trial identifiers [1] 317532 0
Nil
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
Parkinson's disease 342273 0
Condition category
Condition code
Neurological 338386 338386 0 0
Parkinson's disease

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
Oral administration of a single dose of Madopar (100 mg levodopa / 25 mg benserazide) or placebo, administered in a randomised, double-blind design. Madopar is a dopamine precursor that increases dopamine availability in the brain. Placebo will be a vitamin C tablet.
Dose: Madopar (100mg levodopa / 25 mg benserazide)
Duration of treatment: single dose, one session.
Adherence ensured by supervised in-person ingestion.
Mode of delivery: Oral tablet (crushed tablet dispersed in orange juice)
Intervention code [1] 334327 0
Treatment: Drugs
Description of the comparator or control
Placebo control: a single oral dose of an over-the-counter vitamin tablet, crushed and dispersed in orange juice, administered under identical conditions to the active treatment.
Control group
Placebo

Outcomes
Primary outcome [1] 345700 0
Performance on behavioural tasks assessing learning and cognition. Learning and cognition are assessed as a composite primary outcome..
Timepoint [1] 345700 0
Assessed starting approximately 30–45 minutes post-drug/placebo ingestion (coinciding with peak drug levels), continuing for up to of 2 hours post-ingestion. Follow-up sessions of up to 6 months after the intervention will be used to assess lasting effects of the intervention.
Primary outcome [2] 345701 0
Brain activity during motor learning and cognitive tasks, assessed via electroencephalography (EEG; 64-channel active electrode system), measured within a single session approximately 30–45 minutes post-ingestion.
Timepoint [2] 345701 0
Assessed within a single session, approximately 30–45 minutes post-ingestion (coinciding with peak drug levels), with physiological monitoring (blood pressure and heart rate) continuing for up to of 2 hours post-ingestion. Follow-up sessions of up to 6 months after the intervention will be used to assess lasting effects of the intervention.
Primary outcome [3] 345702 0
Eye-tracking
Timepoint [3] 345702 0
Assessed within a single session, approximately 30–45 minutes post-ingestion (coinciding with peak drug levels), with physiological monitoring (blood pressure and heart rate) continuing for up to of 2 hours post-ingestion. Follow-up sessions of up to 6 months after the intervention will be used to assess lasting effects of the intervention.
Secondary outcome [1] 462964 0
Subjective mood
Timepoint [1] 462964 0
Baseline (pre-intervention), at 30 minute intervals post intervention during the first (intervention) session (the Madopar/Placebo session)
Secondary outcome [2] 462965 0
Blood pressure and heart rate. This will be assessed as a composite secondary outcome.
Timepoint [2] 462965 0
Baseline (pre-intervention), at 30 minute intervals post intervention during the first (intervention) session (the Madopar/Placebo session)

Eligibility
Key inclusion criteria
Aged 18 years or older
Neurologically intact
No current or past diagnosis of neurological or psychiatric conditions
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
Yes
Key exclusion criteria
Current use of psychoactive medications or substances (including antidepressants, ADHD medications, anti-anxiety medications, sedatives, or recreational drugs)
History of neurological conditions (e.g. Parkinson's disease, epilepsy, stroke, traumatic brain injury)
History of psychiatric conditions (e.g. depression, anxiety, bipolar disorder, schizophrenia)
History of heart problems or uncontrolled cardiovascular conditions
Current use of medications that alter blood pressure or interact with MAO inhibitors
Pregnant or breastfeeding
Consumption of nicotine, energy drinks, or excessive caffeine (>250 mg) on the day of Madopar consumption
Inability or unwillingness to complete study procedures

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation concealment via a randomisation list, with preparation and administration of active treatment and placebo conducted by an experimenter separate from the one conducting behavioural data collection.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation list will be created using a computer-generated random sequence
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Phase 1
Type of endpoint/s
Pharmacodynamics
Statistical methods / analysis
Sample size was determined based on effect sizes observed in prior work by the research team examining dopaminergic effects on motor learning and cognition (Le…Sample size was determined based on effect sizes observed in prior work by the research team examining dopaminergic effects on motor learning and cognition (Leow et al., 2023; Leow et al., 2024a; Leow et al., 2024b). A sample of 30 participants per group (total N = 60) is targeted. Bayesian stopping rules will be used to determine sufficiency of the sample size.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
6/07/2026
Actual
Date of last participant enrolment
Anticipated
31/12/2030
Actual
Date of last data collection
Anticipated
30/06/2031
Actual
Sample size
Target
300
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA

Funding & Sponsors
Funding source category [1] 322093 0
University
Name [1] 322093 0
Edith Cowan University
Country [1] 322093 0
Australia
Primary sponsor type
University
Name
Edith Cowan University
Address
Country
Australia
Secondary sponsor category [1] 324984 0
None
Name [1] 324984 0
Address [1] 324984 0
Country [1] 324984 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 320622 0
Edith Cowan University Human Research Ethics Committee
Ethics committee address [1] 320622 0
Ethics committee country [1] 320622 0
Australia
Date submitted for ethics approval [1] 320622 0
07/12/2025
Approval date [1] 320622 0
12/06/2026
Ethics approval number [1] 320622 0
REMS NO: 2025-07121-LEOW

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 151078 0
Dr Li-Ann Leow
Address 151078 0
Edith Cowan University, Joondalup campus, Building 30, Level 2, 270 Joondalup Drive, Joondalup WA 6027
Country 151078 0
Australia
Phone 151078 0
+61863043139
Fax 151078 0
Email 151078 0
[email protected]
Contact person for public queries
Name 151079 0
Li-Ann Leow
Address 151079 0
Edith Cowan University, Joondalup campus, Building 30, Level 2, 270 Joondalup Drive, Joondalup WA 6027
Country 151079 0
Australia
Phone 151079 0
+61863043139
Fax 151079 0
Email 151079 0
[email protected]
Contact person for scientific queries
Name 151080 0
Li-Ann Leow
Address 151080 0
Edith Cowan University, Joondalup campus, Building 30, Level 2, 270 Joondalup Drive, Joondalup WA 6027
Country 151080 0
Australia
Phone 151080 0
+61863043139
Fax 151080 0
Email 151080 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.