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Trial registered on ANZCTR


Registration number
ACTRN12616001647426
Ethics application status
Approved
Date submitted
18/03/2016
Date registered
29/11/2016
Date last updated
1/07/2019
Date data sharing statement initially provided
1/07/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
Are the broad cognitive improvements seen with tDCS in healthy controls a result of general or specific effects?
Scientific title
Are the broad cognitive improvements seen with tDCS in healthy controls a result of general or specific effects?
Secondary ID [1] 288799 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cognitive function
298066 0
Condition category
Condition code
Neurological 298229 298229 0 0
Studies of the normal brain and nervous system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This is a randomised double-blind placebo-controlled within-subjects design. Participants will receive 20 minutes of either active or sham transcranial direct current stimulation (tDCS). Each participant will attend the Monash Alfred Psychiatry Research Centre on two occasions at least 72 hours apart.

Active tDCS will be delivered using electrodes placed within the Starstim system cap. The anode, or activating, electrode will be placed over F3 according to the 10-20 international system for EEG placement, which has been determined to be an accurate estimate of the left DLPFC. The cathodal, or reference, electrode will be placed over the right supraorbital space. Stimulation will be applied at 0.028 ma/cm for 20mins.
Sham tDCS is achieved by switching off stimulation after approx. 30s ; which occurs within the software of the Starstim system allowing for administrator and patient blinding.
Intervention code [1] 294249 0
Treatment: Devices
Comparator / control treatment
Design is within-subject. The session order of participants (i.e. active then sham; sham then active) will be randomized and counterbalanced using a computer-generated list. The sham condition will act as a control.
Control group
Placebo

Outcomes
Primary outcome [1] 297731 0
The primary outcome measures will be the accuracy and RT measures from the following cognitive task:
a..Reaction time task: This will require participants to respond with a button press when an X appears on the computer screen before them. (duration 5 mins). This task is a measure of attention and processing speed.
Timepoint [1] 297731 0
Cognitive tasks will be completed at three time points:
Baseline/Time 1: Before 20 minutes of tDCS
Post Stimulation/Time 2: Immediately following tDCS
Delay/ Time 3: After a 30 minute delay
Primary outcome [2] 300307 0
The primary outcome measures will be the accuracy and RT measures from the following cognitive task:

b .Speed of information processing task: In this task two different stimuli will appear on a computer screen (either an A or an X). Participants will be required to respond with a button press only when the letter A appears on the screen (duration 5 mins). This task is a measure of attention and processing speed.
Timepoint [2] 300307 0
Cognitive tasks will be completed at three time points:
Baseline/Time 1: Before 20 minutes of tDCS
Post Stimulation/Time 2: Immediately following tDCS
Delay/ Time 3: After a 30 minute delay
Primary outcome [3] 300308 0
The primary outcome measures will be the accuracy and RT measures from the following cognitive task:
c..Working memory task: The working memory assessment will consisted of 5 minutes of the 2-back and 5 minutes of the 3-back. For the n back tasks a (pseudo-) random series of the letters A to J are presented consecutively and participants are required to respond with a button press when the presented letter was the same as the letter presented either 2 or 3 trials earlier. (duration 10 mins)
Timepoint [3] 300308 0
Cognitive tasks will be completed at three time points:
Baseline/Time 1: Before 20 minutes of tDCS
Post Stimulation/Time 2: Immediately following tDCS
Delay/ Time 3: After a 30 minute delay
Secondary outcome [1] 322040 0
The secondary outcome will be electrophysiological:
The electrical activity of the brain will be recorded using the StarStim Enobio System (Neurolectrics, Spain). We will use an 8 electrode array and mastoid electrodes will serve as the reference.
Timepoint [1] 322040 0
EEG will be collected with participants at rest before and directly after 20 minutes of tDCS stimulation.
Secondary outcome [2] 329662 0
This is the fourth primary outcome measure and includes accuracy and RT measures from the following cognitive task:

d..Social Decision Making task: This task will require participants to answer a series of questions with either YES or No responses via a button box (i.e. Are you in Paris?). They will be instructed for each question to either tell the truth or lie. (duration 5 mins). This task is a measure of executive function.
Timepoint [2] 329662 0
Cognitive task will be completed at three time points:
Baseline/Time 1: Before 20 minutes of tDCS
Post Stimulation/Time 2: Immediately following tDCS
Delay/ Time 3: After a 30 minute delay

Eligibility
Key inclusion criteria
Inclusion Criteria
1. Are voluntary and competent to consent,
2. Are right handed,
3. Are between the ages of 18 and 45 years,
4. Are native English speakers
5. Have no history of neurological illness, mental illness or traumatic brain injury.
Minimum age
18 Years
Maximum age
45 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Exclusion Criteria
1. Are pregnant or lactating,
2. Currently taking any psychoactive medications,
3. Have metal anywhere in the head, except the mouth. This includes metallic objects such as screws, plates and clips from surgical 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)
The session order of participants (i.e. active then sham; sham then active) will be randomized and counterbalanced using a computer-generated list. As each new participant is enrolled they will be allocated to the randomisation. A researcher not involved in data collection will conduct the randomisation and only they will have access to the file.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
All statistical analysis will be conducted using SPSS Version 20. Analysis of co-variance (ANCOVA) will be used to investigate the change in working memory and social decision making after controlling for change in reaction time and speed of information processing between the two conditions (active tDCS, sham tDCS). ANOVAs will be utilised to investigate any changes in EEG measure from pre to post between the two conditions (i.e. active tDCS, sham tDCS). Post hoc analysis will be conducted to tease out any main effects.

A total of 50 participants will be recruited. The primary outcome measures will be behavioural, i.e. the reaction time, and where relevant the accuracy, results from each of the cognitive tasks undertaken. We will also analyses differences in the relevant EEG data for each of the tasks. Multiple studies investigating tDCS have found group differences in cognitive performance and EEG activity with groups of this size or smaller (Hoy et al, 2013; Wirth et al., 2011). No formal power calculation was conducted.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 14126 0
Epworth Rehabilitation Camberwell - Camberwell
Recruitment postcode(s) [1] 26931 0
3124 - Camberwell

Funding & Sponsors
Funding source category [1] 293167 0
Self funded/Unfunded
Name [1] 293167 0
A/Prof Kate Hoy
Address [1] 293167 0
Monash Alfred Psychiatry research centre (MAPrc)
Level 4,
607 St Kilda Road
Melbourne
Victoria
3004
Country [1] 293167 0
Australia
Primary sponsor type
Individual
Name
A/ Prof Kate Hoy
Address
Monash Alfred Psychiatry research centre (MAPrc)
Level 4,
607 St Kilda Road
Melbourne
Victoria
3004
Country
Australia
Secondary sponsor category [1] 291960 0
None
Name [1] 291960 0
Address [1] 291960 0
Country [1] 291960 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 294657 0
Alfred Health Ethics Committee
Ethics committee address [1] 294657 0
Alfred Hospital
55 Commercial Rd,
Prahran,
VIC 3181
Ethics committee country [1] 294657 0
Date submitted for ethics approval [1] 294657 0
26/11/2015
Approval date [1] 294657 0
30/11/2015
Ethics approval number [1] 294657 0
536/15

Summary
Brief summary
The aim of the research project is to investigate whether the broad improvements seen across cognitive domains following tDCS in the healthy population are a result of general effects (i.e. improving speed of information processing) or specific effects (i.e. improving working memory capacity or social decision making ability).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 64510 0
A/Prof Kate Hoy
Address 64510 0
Monash Alfred Psychiatry research centre (MAPrc)
Level 4,
607 St Kilda Road
Melbourne
VIC
3004
Country 64510 0
Australia
Phone 64510 0
+613 9076 5034
Fax 64510 0
Email 64510 0
kate.hoy@monash.edu
Contact person for public queries
Name 64511 0
A/Prof Kate Hoy
Address 64511 0
Monash Alfred Psychiatry research centre (MAPrc)
Level 4,
607 St Kilda Road
Melbourne
VIC
3004
Country 64511 0
Australia
Phone 64511 0
+613 9076 5034
Fax 64511 0
Email 64511 0
kate.hoy@monash.edu
Contact person for scientific queries
Name 64512 0
A/Prof Kate Hoy
Address 64512 0
Monash Alfred Psychiatry research centre (MAPrc)
Level 4,
607 St Kilda Road
Melbourne
VIC
3004
Country 64512 0
Australia
Phone 64512 0
+613 9076 5034
Fax 64512 0
Email 64512 0
kate.hoy@monash.edu

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
Summary results
No Results