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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Enhancing Working Memory with Transcranial Direct Current Stimulation: The Impact of Combined Prefrontal and Parietal Stimulation
Scientific title
Enhancing Working Memory with Transcranial Direct Current Stimulation: The Impact of Combined Prefrontal and Parietal Stimulation in Healthy Volunteers
Secondary ID [1] 286390 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Working memory in healthy adults 294536 0
Condition category
Condition code
Mental Health 294844 294844 0 0
Studies of normal psychology, cognitive function and behaviour
Neurological 295421 295421 0 0
Studies of the normal brain and nervous system

Study type
Description of intervention(s) / exposure
Transcranial direct current stimulation (tDCS) is a safe, non-invasive, painless technique which has the capacity to temporarily alter cortical excitability and has been shown to improve working memory performance. In this study it is delivered to the dorsolateral prefrontal cortex (DLPFC) and Parietal cortex.

This study employs a randomised, crossover design where participants take part in three separate treatment sessions at least 72 hours apart. Each session involves administration of either active tDCS (either over the DLPFC alone, or DLPFC and parietal cortex), or sham tDCS.

Specifically, participants will receive:

a) Anodal tDCS over the left DLPFC (1.5 mA, 15 minutes)
b) Anodal tDCS over the DLPFC and bilateral parietal cortices (1.5 mA, 15 minutes)
c) Sham tDCS either over the DLPFC or DLPFC and bilateral parietal cortices (counterbalanced, 15 minutes)
Intervention code [1] 291458 0
Treatment: Devices
Comparator / control treatment
The comparator treatment is: Sham tDCS (15 minutes). In the sham treatment, tDCS stimulation is ramped-up to 1.5 mA, held at this intensity for several seconds, then ramped down to 0 mA. This technique generates a sensation on the scalp akin to active tDCS, but does not produce any tangible changes in cortical excitability. Sham stimulation will be delivered over either the DLPFC alone (50% of participants), or DLPFC + PPC (50% of participants), with each participant being randomly assigned to one of these two groups.
Control group

Primary outcome [1] 294607 0
N-back task (2-Back, 3-Back) accuracy and reaction time
Digit-span (forwards and backwards)
Timepoint [1] 294607 0
Two separate time-points for each session:
a) Five minutes after tDCS treatment
b) 30 minutes after tDCS treatment
Primary outcome [2] 294608 0
TMS-EEG evoked potentials
Timepoint [2] 294608 0
a) Five minutes after tDCS treatment
b) 30 minutes following tDCS treatment
Secondary outcome [1] 313708 0
EEG oscillations (theta ERS and alpha ERD and gamma frequency)
Timepoint [1] 313708 0
Two timepoints for each session. EEG oscilations recorded during n-back task:

a) Five minutes after tDCS treatment
b) 30 minutes following tDCS treatment

Key inclusion criteria
1) Right-handed adults who have the capacity to provide informed consent.

2) Have no personal history of psychiatric or neurological illness
Minimum age
18 Years
Maximum age
60 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1) Anyone suffering from an unstable medical condition, neurological or psychiatric disorder or any history of a seizure disorder or who are currently pregnant or breastfeeding.

2) Anyone with any metallic implants in the head, a pacemaker, cochlear implant medication pump or other electronic device.

3) Anyone currently taking any psychoactive medications.

4) Professional drivers are not able to participate due to the, albeit relatively low, risk of seizure as this could affect their employment.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
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

Intervention assignment
Other design features
Participants will receive both active and sham stimulation in a cross-over design employing a 72 hour wash out period.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 290963 0
Name [1] 290963 0
Monash University
Address [1] 290963 0
Wellington Road,
Clayton, VIC 3168
Country [1] 290963 0
Primary sponsor type
Monash University
Wellington Road,
Clayton, VIC 3168
Secondary sponsor category [1] 289644 0
Name [1] 289644 0
Address [1] 289644 0
Country [1] 289644 0

Ethics approval
Ethics application status
Ethics committee name [1] 292560 0
Alfred Health Human Ethics Committee
Ethics committee address [1] 292560 0
Alfred Hospital
Commercial Road
Prahran, VIC 3181
Ethics committee country [1] 292560 0
Date submitted for ethics approval [1] 292560 0
Approval date [1] 292560 0
Ethics approval number [1] 292560 0
Ethics committee name [2] 294286 0
Monash University Human Research Ethics Committee
Ethics committee address [2] 294286 0
Wellington Road,
Clayton VIC, 3168
Ethics committee country [2] 294286 0
Date submitted for ethics approval [2] 294286 0
Approval date [2] 294286 0
Ethics approval number [2] 294286 0
CF15/2285 - 2015000920

Brief summary
tDCS involves the application of a very weak electrical current to the scalp, which acts to modulate the excitability of underlying cortical neurons, thereby altering their function. tDCS is both safe and painless, and can induce changes in brain function which are measurable for over an hour after the cessation of stimulation. In order for tDCS to be optimally utilised, however, research which directly compares different stimulation parameters is greatly needed.

To date, several studies have demonstrated the capacity for tDCS to enhance performance during working memory (WM) tasks when it is applied over prefrontal brain regions (e.g., DLPFC). However, despite encouraging initial results, tDCS has thus far only been able to produce modest levels of cognitive enhancement in healthy individuals. One way of potentially improving the effectiveness of this technique would be to apply it concurrently over a combination of brain regions known to be involved in WM.

Therefore, this project specifically aims to compare the effects of tDCS delivered over either the left DLPFC alone, or the left DLPFC in combination with the left parietal lobe. Simultaneous stimulation of prefrontal and parietal brain regions will be achieved using a multifocal ‘high-definition’ stimulation montage which allows for accurate stimulation of two independent cortical targets. The parietal brain region was chosen as the additional stimulation site due to its known involvement in WM. Both behavioural (WM performance) and neurophysiological (EEG, TMS-EEG) data will be utilised to assess the effectiveness of this technique.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 55938 0
Mr Aron Hill
Address 55938 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, 3004
Country 55938 0
Phone 55938 0
+61 3 9076 8691
Fax 55938 0
Email 55938 0
Contact person for public queries
Name 55939 0
Mr Aron Hill
Address 55939 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, 3004
Country 55939 0
Phone 55939 0
+61 3 9076 8691
Fax 55939 0
Email 55939 0
Contact person for scientific queries
Name 55940 0
Mr Aron Hill
Address 55940 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, 3004
Country 55940 0
Phone 55940 0
+61 3 90768691
Fax 55940 0
Email 55940 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
We do not have ethical approval for IPD sharing.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Journal publication details
Publication date and citation/details [1] 673 0
https://doi.org/10.1016/j.brs.2018.06.005. 18 June 2018.
Attachments [1] 673 0
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary