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

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 evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT03845920
Recruitment Status : Recruiting
First Posted : February 19, 2019
Last Update Posted : April 4, 2019
Sponsor:
Information provided by (Responsible Party):
Sheffield Hallam University

Brief Summary:

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.


Condition or disease Intervention/treatment Phase
Modulation of Cognitive Flexibility by Transcranial Direct Current Stimulation, Tyrosine Administration and Polymorphisms in the COMT Gene Combination Product: tdcs (sham/anodal) + drug (placebo/tyrosine) Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 32 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Modulation of Cognitive Flexibility by Transcranial Direct Current Stimulation, Tyrosine Administration and Polymorphisms in the COMT Gene
Actual Study Start Date : February 18, 2019
Estimated Primary Completion Date : September 30, 2019
Estimated Study Completion Date : September 30, 2019

Resource links provided by the National Library of Medicine

Drug Information available for: Tyrosine

Arm Intervention/treatment
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.





Primary Outcome Measures :
  1. 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

  2. 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

  3. 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)



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 30 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03845920


Contacts
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Contact: Luca Aquili, Ph.D. + 44 (0) 114 225 ext 6991 luca.aquili@shu.ac.uk
Contact: Ann Macaskill, Ph.D. 44 (0)114 225 ext 4604 a.macaskill@shu.ac.uk

Locations
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United Kingdom
Psychology labs Recruiting
Sheffield, South Yorkshire, United Kingdom, S10 2BQ
Contact: Lee Wallace, BSc    0114 225 ext 5953    l.j.wallace@shu.ac.uk   
Contact: Jordan Crawford, MSc    0114 225 ext 3554    j.d.crawford@shu.ac.uk   
Sponsors and Collaborators
Sheffield Hallam University
Investigators
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Principal Investigator: Luca Aquili, Ph.D. Sheffield Hallam University
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Responsible Party: Sheffield Hallam University
ClinicalTrials.gov Identifier: NCT03845920    
Other Study ID Numbers: SheffieldHallamAquili2019
First Posted: February 19, 2019    Key Record Dates
Last Update Posted: April 4, 2019
Last Verified: April 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No