Mod of Cognitive Flexibility by tDCS, Tyrosine Polymorphisms in the COMT Gene

April 2, 2019 updated by: Sheffield Hallam University

Modulation of Cognitive Flexibility by Transcranial Direct Current Stimulation, Tyrosine Administration and Polymorphisms in the COMT Gene

The current study would examine whether increases in endogenous dopaminergic activity via tyrosine and the (presumed) excitation of these by anodal tDCS of the dlPFC could causally be related to cognitive flexibility as measured by task switching and reversal learning.

Additionally, the study will test whether the Val158Met-polymorphism in the catechol- O-methyltransferase (COMT) gene could also predict the effect of TYR supplementation, as this gene is involved in DA degradation in the prefrontal cortex.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Unknown

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
32

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 30 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • • Either male or female

    • Between 18 and 30 years
    • You are in good health
    • You agree to fast overnight prior to testing

Exclusion Criteria:

  • • Are suffering from cardiac, hepatic, renal, neurological disorders

    • Damaged or diseased skin on your face and scalp, or a sensitive scalp
    • A history of alcohol or drug addiction, or severe psychiatric illness
    • Drug treatment which may lower seizure threshold (i.e. epilepsy)
    • Pregnancy
    • Sleep deprivation (less than 6 hours a day)
    • A history of migraine or headaches
    • A history of taking antidepressants
    • A history of taking tyrosine supplements

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: tDCS sham + placebo
tDCS= transcranial direct current stimulation drugs= placebo (cellulose [2 grams])
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS sham + tyrosine
tDCS= transcranial direct current stimulation drugs= tyrosine (2 grams)
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS anodal + placebo
tDCS= anodal transcranial direct current stimulation of the dorsolateral prefrontal cortex drugs= placebo (cellulose [2 grams])
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS anodal +tyrosine
tDCS= anodal transcranial direct current stimulation of the dorsolateral prefrontal cortex drugs= tyrosine (2 grams)
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Wisconsin Card Sorting Test (WCST) performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in perseverative errors in the WCST
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Probabilistic Reversal Learning (PRL) performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in reversal errors in the WCST
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Flanker Task performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in conflict cost (defined as the difference in reaction time between congruent and incongruent responses)
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sheffield Hallam University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 18, 2019

Primary Completion (Anticipated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 30, 2019

Study Completion (Anticipated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 11, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 15, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 19, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 4, 2019

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 2, 2019

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2019

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SheffieldHallamAquili2019

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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