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

Sponsor

Sheffield Hallam University (Other)

Overall Status

Unknown status

CT.gov ID

NCT03845920

Collaborator

(none)

Enrollment

Location

Arms

7.4

Anticipated Duration (Months)

4.3

Patients Per Site Per Month

Study Details

Study Description

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)	N/A

Study Design

Study Type:

Interventional

Anticipated 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 :

Feb 18, 2019

Anticipated Primary Completion Date :

Sep 30, 2019

Anticipated Study Completion Date :

Sep 30, 2019

Arms and Interventions

Arm	Intervention/Treatment
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.

Outcome Measures

Primary Outcome Measures

Wisconsin Card Sorting Test (WCST) performance [Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.]
Measuring change in perseverative errors in the WCST
Probabilistic Reversal Learning (PRL) performance [Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.]
Measuring change in reversal errors in the WCST
Flanker Task performance [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)

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 30 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Psychology labs	Sheffield	South Yorkshire	United Kingdom	S10 2BQ

Sponsors and Collaborators

Sheffield Hallam University

Investigators

Principal Investigator: Luca Aquili, Ph.D., Sheffield Hallam University

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

Responsible Party:

Sheffield Hallam University

ClinicalTrials.gov Identifier:

NCT03845920

Other Study ID Numbers:

SheffieldHallamAquili2019

First Posted:

Feb 19, 2019

Last Update Posted:

Apr 4, 2019

Last Verified:

Apr 1, 2019

Individual Participant Data (IPD) Sharing Statement:

Plan to Share IPD:

Studies a U.S. FDA-regulated Drug Product:

Studies a U.S. FDA-regulated Device Product:

Study Results

No Results Posted as of Apr 4, 2019