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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Cognitive and Neurophysiologic Effects of Transcranial Direct Current Stimulation: The Impact of Concurrent Task Performance
Scientific title
Cognitive and Neurophysiologic Effects of Transcranial Direct Current Stimulation: The Impact of Concurrent Task Performance
Secondary ID [1] 288412 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Working memory in healthy adults 297424 0
Condition category
Condition code
Mental Health 297609 297609 0 0
Studies of normal psychology, cognitive function and behaviour
Neurological 297644 297644 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 and painless neuromodulatory technology which has the capacity to temporarily alter cortical excitability and has been shown to improve working memory performance in previous trials. In this study it is delivered to the left dorsolateral prefrontal cortex (DLPFC).

This study employs a randomised, crossover design in which participants take part in three seperate testing sessions held on different days. A washout period of at least 72 hours between sessions will be employed to reduce any carry over effects of stimulation. Each session involves the administration of either an active or sham (placebo) form of anodal tDCS (a-tDCS). Active a-tDCS will be administered at a stimulation strength of 1.5 mA for 15 minutes. Sham stimulation will involve 30 seconds of stimulation before the stimulator is ramped down to 0 mA.

Specifically, in each testing session participants will receive.

1) a-tDCS delivered alone
2) a-tDCS combined with a cognitive task
3) sham tDCS combined with a cognitive task

The cognitive task administered will be a computerised version of the the Adjusting Paced Auditory Serial Addition Test (A-PASAT) which measures both speed of information processing and working memory. In this test, single digits are presented aurally to the participant, who is required to add the two most recently presented numbers and give a response. The duration of the interval between the presented numbers is dependent on the participant's level of correctness in responding, with a correct response decreasing and an incorrect response increasing the time interval between presented digits. The test will be administered for a period of approximately 10 minutes.
Intervention code [1] 293724 0
Treatment: Devices
Comparator / control treatment
The comparator treatment in this study is sham (placebo) tDCS. In the sham treatment, tDCS stimulation in ramped up to 1.5 mA, held at this intensity for several seconds and then ramped down to 0 mA. This technique has been shown to generate a scalp sensation which is similar to active tDCS without altering cortical excitability.
Control group

Primary outcome [1] 297154 0
Offline working memory performance (N-Back task)
Timepoint [1] 297154 0
10 minutes after tDCS treatment
Secondary outcome [1] 320176 0
Neurophysiological brain changes as recorded with:
1) Resting state EEG
2) Task-related EEG (EEG recorded during N-back tasks)
3) TMS-EEG evoked potentials/osciallations
Timepoint [1] 320176 0
Approximately 10 minutes after tDCS administration
Secondary outcome [2] 320177 0
Online working memory performance (A-PASAT)
Timepoint [2] 320177 0
Assessment with the A-PASAT will commence 3 minutes after tDCS administration commences and will continue for 10 minutes.

Key inclusion criteria
1) Healthy 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
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] 292761 0
Name [1] 292761 0
Monash University
Address [1] 292761 0
Wellington Road, Clayton, VIC 3168
Country [1] 292761 0
Primary sponsor type
Monash University
Wellington Road, Clayton VIC 3168
Secondary sponsor category [1] 291491 0
Name [1] 291491 0
Alfred Hospital
Address [1] 291491 0
Commercial Road, Melbourne, Victoria 3004
Country [1] 291491 0

Ethics approval
Ethics application status
Ethics committee name [1] 294246 0
Alfred Health Human Ethics Committee
Ethics committee address [1] 294246 0
Alfred Hospital,
Commercial Road, Melbourne, Victoria
Ethics committee country [1] 294246 0
Date submitted for ethics approval [1] 294246 0
Approval date [1] 294246 0
Ethics approval number [1] 294246 0
Ethics committee name [2] 294247 0
Monash University Human Research Ethics Committee
Ethics committee address [2] 294247 0
Monash University,
Wellington Road,
Clayton, Victoria 3168
Ethics committee country [2] 294247 0
Date submitted for ethics approval [2] 294247 0
Approval date [2] 294247 0
Ethics approval number [2] 294247 0
CF16/185 - 2016000081

Brief summary
A profusion of imaging and lesion based research now indicates that the dorsolateral prefrontal
cortex (DLPFC) is a vital substrate for a number of important cognitive functions, particularly working memory (WM). Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique which applies a very weak current to the scalp which can transiently alter underlying brain function as well as behaviour. When applied over the DLPFC, tDCS has been shown to both enhance WM performance in healthy individuals and ameliorate its dysfunction in clinical cohorts. These changes are hypothesised to be due the ability for tDCS to alter the excitability of neurons within the brain, which in tern leads to neuroplasticity-related changes in cognitive function. Nevertheless, to date, the level with which tDCS can modulate cognition remains relatively modest and, as such, research is needed to explore ways of improving the clinical efficacy of this technology. There is currently some limited evidence to suggest that combining tDCS delivery with a cognitive task may have a synergistic effect, leading to greater subsequent improvements in cognition. However, this finding has yet to be systematically explored. The current project, therefore, aims to investigate this potential task-dependency effect in detail in a cohort of healthy adult participants utilising both behavioural and neurophysiological outcome measures.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 63042 0
Mr Aron Hill
Address 63042 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, Victoria 3004
Country 63042 0
Phone 63042 0
+61 3 9076 8691
Fax 63042 0
Email 63042 0
Contact person for public queries
Name 63043 0
Mr Aron Hill
Address 63043 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, Victoria 3004
Country 63043 0
Phone 63043 0
Fax 63043 0
Email 63043 0
Contact person for scientific queries
Name 63044 0
Mr Aron Hill
Address 63044 0
Monash Alfred Psychiatry Research Centre (MAPrc),
Level 4, 607 St Kilda Road
Melbourne, Victoria 3004
Country 63044 0
Phone 63044 0
Fax 63044 0
Email 63044 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary