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Trial registered on ANZCTR

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

Titles & IDs
Public title
Can Transcranial Electrical Stimulation enhance working memory in schizophrenia and healthy controls?
Scientific title
Non-invasive brain stimulation and working memory enhancement in schizophrenia and healthy controls: investigating transcranial Direct Current Stimulation (tDCS) and transcranial Alternating Current Stimulation (tACS).
Secondary ID [1] 279868 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Schizophrenia / Schizoaffective disorder 285657 0
Condition category
Condition code
Mental Health 285835 285835 0 0

Study type
Description of intervention(s) / exposure
Anodal transcranial direct current stimulation (tDCS) at 2mA intensity, and anodal transcranial Alternating Current Stimulation (tACS) at 1mA intensity with gamma frequency range of 30-40Hz. This will be applied to the left dorsolateral prefrontal cortex for 20 minutes using a neuroConn GBH/Eldith DC Stimulator. tDCS will be delivered during three sessions (one tDCS, one tACS, and one sham tDCS) that will be one week apart.
Intervention code [1] 284099 0
Treatment: Devices
Comparator / control treatment
Sham transcranial direct current stimulation (tDCS). This will involve placing the electrodes in the same position as for active tDCS, however stimulation will be ceased after 30 seconds (so as to generate the same initial sensation and ensure blinding is maintained).
Control group

Primary outcome [1] 286343 0
A statistically significant improvement in performance on a working memory task (i.e. N-Back) following application of tDCS/tACS stimulation, both in patients with schizophrenia/ schizoaffective disorder and in healthy controls.
Timepoint [1] 286343 0
Before and after application of tDCS/tACS stimulation
Primary outcome [2] 286344 0
A statistically significant improvement in performance on the N-Back working memory task following application of anodal tDCS or tACS stimulation, compared with sham stimulation, both in patients with schizophrenia/ schizoaffective disorder and in healthy controls.
Timepoint [2] 286344 0
Comparison of conditions - Session 1 vs Session 2 vs Session 3.

Participants' performance on the N-Back task will be measured for each session, both during and immediately after tDCS/tACS/sham stimulation. At the end of the trial, a final analysis will be conducted to compare participants' performance on the N-back across the three stimulation conditions.
Secondary outcome [1] 295891 0
Timepoint [1] 295891 0

Key inclusion criteria
Participants with schizophrenia will be included if they:
- are voluntary and competent to consent
- have a diagnosis of Schizophrenia or Schizoaffective Disorder as confirmed by the Structure Clinical Interview for the DSM-IV (SCID-IV)

Healthy individuals will be included if they:
- have capacity to consent
- have no personal history of psychiatric illness (lifetime) - based on self report.
Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Patients with schizophrenia will be excluded if they:
- have a a DSM-IV history of substance abuse or dependence in the last 6 months
- have a concomitant major and/or unstable medical or neurologic illness
- are currently taking carbamazepine
- are currently pregnant or lactating
- have metal anywhere in the head, except the mouth (this includes metallic objects such as screws and clips from surgical procedures)

Healthy participants will be excluded if they:
- have an unstable medical condition, neurological disorder or are currently pregnant or lactating
- have metal in the cranium, a pacemaker, cochlear implant medication pump or other electronic device

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
This is a double-blind study. Neither the participant nor the researcher conducting the sessions will know what type of stimulation the participant is receiving during each session. The Chief Investigator, who will be unblinded, will provide a unique code to be entered into the tDCS stimulator, which will determine the stimulation condition and settings, thus allowing the second researcher to remain blinded. The stimulation condition will be counterbalanced across participants.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

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] 284628 0
Name [1] 284628 0
Accelerator Program Funding, Monash University
Address [1] 284628 0
Monash University
Wellington Rd
Clayton VIC 3800
Country [1] 284628 0
Primary sponsor type
Dr. Kate Hoy
MAPrc, Level 1, Old Baker Building
The Alfred
Melbourne VIC 3004
Secondary sponsor category [1] 283552 0
Name [1] 283552 0
Address [1] 283552 0
Country [1] 283552 0

Ethics approval
Ethics application status
Ethics committee name [1] 286618 0
Alfred Human Research Ethics Committee
Ethics committee address [1] 286618 0
Ethics Office
Ground Floor, Linay Pavilion
The Alfred
Melbourne VIC 3004
Ethics committee country [1] 286618 0
Date submitted for ethics approval [1] 286618 0
Approval date [1] 286618 0
Ethics approval number [1] 286618 0

Brief summary
Working memory difficulties are commonly experienced by individuals with schizophrenia and schizoaffective disorder. These difficulties have been shown to negatively influence patients’ psychosocial functioning. Any technique that may enhance working memory would therefore be very useful. Recent research has suggested that brain stimulation, and in particular transcranial Electrical Stimulation (TES) techniques such as transcranial Direct Current Stimulation (tDCS) and transcranial Alternating Current Stimulation (tACS), may have a role to play in improving cognition. TES techniques have been shown to be a safe and non-invasive way of modulating brain activity, by applying a very weak electrical current (1-2mA) to the cortex via electrodes that are placed on the scalp. While tDCS has been shown to improve working memory in a number of conditions, to date there have been no tDCS or tACS studies looking at the enhancement of working memory in schizophrenia.

The current study will investigate whether working memory can be improved using tDCS and tACS in healthy participants and patients with schizophrenia or schizoaffective disorder. Further, the study aims to establish the most effective stimulation parameters for optimal working memory enhancement. Twenty healthy controls and 20 individuals with schizophrenia or schizoaffective disorder will attend 3 sessions at The Alfred hospital, each session involving a different type of TES (1mA tACS, 2ma tDCS, or sham stimulation). Participants' performance on a working memory task will be assessed following application of the stimulation, and brain activity will be monitored throughout the tasks using electroencephalography (EEG).
Trial website
Trial related presentations / publications
Hoy KE, Bailey NW, Arnold SL, John J, Daskalakis ZJ, Fitzgerald PB. The effect of gamma-tACS on working memory performance in healthy controls. Brain and Cognition. 101; 51-56, 2015

Hoy KE, Whitty D, Bailey NW, Fitzgerald PB. Preliminary investigation of the effects of gamma-tACS on working memory in schizophrenia. Journal of Neural Transmission, 1-8, 2016
Public notes

Principal investigator
Name 33667 0
A/Prof Kate Hoy
Address 33667 0
MAPrc, Level 4 607 St Kilda Road
Melbourne, VIC 3004
Country 33667 0
Phone 33667 0
+61 3 90765034
Fax 33667 0
Email 33667 0
Contact person for public queries
Name 16914 0
Ms Ms. Sara Arnold
Address 16914 0
MAPrc, Level 1, Old Baker Building
The Alfred
Melbourne VIC 3004
Country 16914 0
Phone 16914 0
+61 3 9076 6592
Fax 16914 0
Email 16914 0
Contact person for scientific queries
Name 7842 0
A/Prof Dr. Kate Hoy
Address 7842 0
MAPrc, Level 1, Old Baker Building
The Alfred
Melbourne VIC 3004
Country 7842 0
Phone 7842 0
+61 3 9076 5034
Fax 7842 0
Email 7842 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