Cognitive Effects of tDCS and tRNS in Schizophrenia

Study Overview
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Brief Summary
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The purpose of this study is to investigate the cognitive effects of different electrical stimulation modalities, such as transcranial direct and random-noise stimulation over the dorsolateral prefrontal cortex, in schizophrenia.

Official Title
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Cognitive Effects of Transcranial Direct Current Stimulation (tDCS) and Transcranial Random Noise Stimulation (tRNS) in Schizophrenia: A Random, Crossover Study

Conditions
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Schizophrenia, Cognitive Impairment

Intervention / Treatment
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* Device: transcranial direct current stimulation (tDCS) active stimulator
* Device: transcranial random noise stimulation (tRNS)
* Device: transcranial direct current stimulation (tDCS) sham stimulator


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of schizophrenia based on Diagnostic and Statistical Manual (DSM)5 Being 18-50 years old (male and female) If female, negative urine pregnancy test feasibility for tDCS/tRNS interventions according to safety guidelines stable medication regime, especially for classical neuroleptics and all central nervous system activating medications, if taken, 4-6 weeks before the experiment fluency in the native language right-handed Required written informed consent signed by patients' guardian Exclusion Criteria: pregnancy alcohol or substance dependence comorbid bipolar disorder and mood disorder history of seizure history of neurological disorder history of head injury Presence of ferromagnetic objects in the body that are contraindicated for brain stimulation of the head (pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips, metallic prostheses, permanent eyeliner, implanted delivery pump, or shrapnel fragments)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: tDCS group<br>In tDCS, direct electrical currents at the intensity of 2 mA are generated by an electrical stimulator and are noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes. | Device: transcranial direct current stimulation (tDCS) active stimulator<br>* In tDCS the electrical current is applied directly between electrodes mounted on the head which can can de-or hyperpolarizes resting membrane potential and thereby modulate cortical excitability<br>|
| Active Comparator: tRNS group<br>In tRNS, direct electrical currents at the intensity of 2 mA amplitude (offset at 1 mA) and frequency of 100-640 Hz are generated by an electrical stimulator and are noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes. | Device: transcranial random noise stimulation (tRNS)<br>* Here, an alternating electrical current is applied at a mix of frequencies it is called transcranial random noise stimulation (tRNS), which can be delivered in low (between 0.1-100 Hz) or high (between 101-640 Hz) frequency stimulation<br>|
| Sham Comparator: sham group<br>In sham group, placebo stimulation is generated by an electrical stimulator and is noninvasively delivered to the left and right dorsolateral prefrontal cortex through a pair of saline-soaked sponge electrodes (7×5 cm) for 30 minutes. | Device: transcranial direct current stimulation (tDCS) sham stimulator<br>* Here a sham electrical current is applied directly between electrodes mounted on the head which can can de-or hyperpolarizes resting membrane potential and thereby modulate cortical excitability<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spatial Working Memory behavioral performance | The test begins with a number of coloured squares (boxes) shown on the screen. The aim of this test is that by selecting the boxes and using a process of elimination, the participant should find one yellow 'token' in each of a number of boxes and use them to fill up an empty column on the right-hand side of the screen. | During procedure (4 minutes) | 
| executive function behavioral performance | The participant is shown two displays containing three coloured balls. The test administrator first demonstrates to the participant how to move the balls in the lower display to copy the pattern in the upper display and completes one demonstration problem, where the solution requires one move. The participant must then complete three further problems, one each requiring two moves, three moves, and four moves. Next, the participant is shown further problems and must work out in their head how many moves the solutions require and then select the appropriate box at the bottom of the screen to indicate their response | During procedure (8-10 minutes) | 
| The Positive and Negative Affect Schedule (PANAS) | The Positive and Negative Affect Schedule (PANAS) is a self-report questionnaire that consists of two 10-item scales to measure both positive and negative affect. Each item is rated on a 5-point scale of 1 (not at all) to 5 (very much). | through study completion, an average of 3 weeks |