Effects of Transcranial Direct Current Stimulation on Cognitive Rehabilitation in Schizophrenia

January 12, 2026 updated by: Medical University of Lodz

Evaluation of the Effects of Transcranial Direct Current Stimulation on the Effectiveness of Cognitive Function Rehabilitation Using the RehaCom System in Patients With Schizophrenia (Study Protocol)

The aim of this prospective, randomized, double-blind, placebo-controlled study is to assess whether transcranial direct current stimulation (tDCS) applied prior to RehaCom cognitive training can improve cognitive functioning in individuals diagnosed with schizophrenia.

The study is designed to answer the following main questions:

  • Does the combination of active tDCS and RehaCom cognitive training lead to better performance on CANTAB tests compared to training preceded by sham stimulation?
  • Does tDCS enhance the effectiveness of cognitive rehabilitation by strengthening neuroplasticity mechanisms? Researchers will compare the group receiving active tDCS + RehaCom with the group undergoing sham stimulation + RehaCom to determine whether active stimulation produces greater improvements in cognitive functioning.

Participants will receive tDCS targeting the DLPFC, which was selected due to its key involvement in executive cognitive functions. These include working memory, planning, decision-making, inhibitory control, and the regulation of attention, all of which are relevant for modulating cognitive dysfunction in schizophrenia.

The tDCS will be administered using a battery-powered direct current stimulator (DC-Stimulator PLUS, neuroCare, Germany) through two saline-soaked sponge electrodes (5 cm × 7 cm). According to the International 10-20 system, the anodal electrodes will be positioned over the left DLPFC on the sites corresponding to F3, whereas the cathodal electrode will be placed above the right DLPFC, corresponding to F4. The electrode locations were verified using a computational brain model. All sessions will be conducted over five consecutive days (from Monday to Friday), with a 24-hour interval between sessions. Each participant will complete a total of 15 treatment sessions within a three-week period. Stimulation will be administered using the fixed parameters according to the established literature. For the active tDCS condition, a direct current of 2.0 mA will be applied (corresponding to a total charge of 2.4 C, a current density of 0.57 A/m2, and a charge density of 685.7 C/m2), for 20 minutes with ramp-up and ramp-down periods of 20 seconds each. For sham tDCS, the stimulation will utilize the same active tDCS arrangement, with an intensity of 2.0 mA. However, the current will be applied only for the 20 s ramp-up phase at the beginning and the 20 s ramp-down phase at the end of the stimulation. This protocol preserves blinding by mimicking the initial somatosensory sensations typically associated with active tDCS.

The selection of these parameters is grounded in prior evidence which demonstrates their functional specificity and efficacy in modulating cognitive processes in individuals diagnosed with schizophrenia.

All sessions will be conducted by trained personnel, and adverse events will be regularly monitored throughout the study.

Immediately after each tDCS stimulation, patients will undergo a 30-minute cognitive rehabilitation training session using the RehaCom computer system (HASOMED GmbH, Germany). Previous studies show that the time for which changes in neuronal excitability remain are proportional to the duration of stimulation and current used (Nitsche and Paulus, 2000). Based on these data, the authors assume that following a 20-minute tDCS session, the after-effects should last for at least 30 min (and hence the duration of neurocognitive training will be set at 30 min per session). The following programs will be used each week: day 1 (Monday), 3 (Wednesday) and 5 (Friday): EINK - shopping (different memory functions and selective attention), SUSA - selection of items (sustained attention), WOME - card games (working memory); day 2 (Tuesday) and 4 (Thursday): GEAU - maintaining the set vehicle speed (divided attention), LODE - creating logical sequences (logical reasoning); WOME - card games (working memory). During every session, each program will be applied for ten minutes, using a 17-inch laptop and a dedicated control panel. The following parameters will be set for SUSA: level up 85% and level down 70%; for LODE: upper threshold 90%, bottom threshold 60%, number of tasks per level 10; for WOME: number of tasks 10, repetitions 1, card display time 2000 ms; for GEAU: upper threshold 95%, bottom threshold 80%; for EINK: upper threshold 90%, bottom threshold 80%, repetitions 1, max time 90/300 s.

Participants will:

  • Undergo assessments at three time points (V1 - baseline, V2 - after 3 weeks of intervention, V3 - after 8 weeks).
  • Be evaluated using CANTAB tests, the PANSS and CGI-S scales, and resting-state EEG.

The goal of the study is to determine whether applying tDCS before cognitive training improves executive function rehabilitation outcomes and supports the maintenance of these effects over time compared to cognitive training alone.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Poland
    • Łódź Voivodeship
      • Lodz, Łódź Voivodeship, Poland, 92-216
        • Department of Old Age Psychiatry and Psychotic Disorders

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Adults aged 18-65 years with schizophrenia diagnosed according to DSM-5 criteria (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition)
  2. Ability to provide informed consent for tDCS treatment and use of collected data for research purposes
  3. Mentally stable, may receive pharmacological treatment

Exclusion Criteria:

  1. Contraindications to tDCS, including:

    Implanted electronic devices Metal implants in the head History of seizures Contact allergy to materials used for tDCS stimulation (electrodes)

  2. Pregnancy
  3. Head injury with loss of consciousness or neurosurgery performed within the previous six months
  4. History of stroke, aneurysm, brain tumor, or other conditions causing increased intracranial pressure
  5. Migraines
  6. Substance abuse
  7. Currently receiving electroconvulsive therapy (ECT)

Withdrawal criteria: participation will be discontinued if any of the following occur:

Urgent medical issues Serious adverse events or side effects Participant unwillingness to continue in the trial

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: real tDCS
For the active tDCS condition, a direct current of 2.0 mA will be applied (corresponding to a total charge of 2.4 C, a current density of 0.57 A/m2, and a charge density of 685.7 C/m2), for 20 minutes with ramp-up and ramp-down periods of 20 seconds each.
Procedure: active tDCS
For the active tDCS condition, a direct current of 2.0 mA will be applied (corresponding to a total charge of 2.4 C, a current density of 0.57 A/m2, and a charge density of 685.7 C/m2), for 20 minutes with ramp-up and ramp-down periods of 20 seconds each. The tDCS will be administered using a battery-powered direct current stimulator (DC-Stimulator PLUS, neuroCare, Germany) through two saline-soaked sponge electrodes (5 cm × 7 cm). According to the International 10-20 system, the anodal electrodes will be positioned over the left DLPFC on the sites corresponding to F3, whereas the cathodal electrode will be placed above the right DLPFC, corresponding to F4. The electrode locations were verified using a computational brain model. All sessions will be conducted over five consecutive days (from Monday to Friday), with a 24-hour interval between sessions. Each participant will complete a total of 15 treatment sessions with
Sham Comparator: sham tDCS
For sham tDCS, the stimulation will utilize the same active tDCS arrangement, with an intensity of 2.0 mA. However, the current will be applied only for the 20 s ramp-up phase at the beginning and the 20 s ramp-down phase at the end of the stimulation. This protocol preserves blinding by mimicking the initial somatosensory sensations typically associated with active tDCS.
Procedure: sham tDCS
For sham tDCS, the stimulation will utilize the same active tDCS arrangement, with an intensity of 2.0 mA. However, the current will be applied only for the 20 s ramp-up phase at the beginning and the 20 s ramp-down phase at the end of the stimulation. This protocol preserves blinding by mimicking the initial somatosensory sensations typically associated with active tDCS.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
parameters in the Cambridge Neuropsychological Test Automated Battery (CANTAB): DMS; ERT; MTT; OTS; PAL; RTI; RVP; SWM.
Time Frame: From enrollment to the end of treatment at 8 weeks
The primary outcome of the study is the evaluation of the effect of tDCS intervention on the effectiveness of cognitive function rehabilitation using the RehaCom system in patients with schizophrenia. The scope of these changes will be assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB) (Cambridge Cognition, UK). The CANTAB test will be administered at three time points: before the initiation of the stimulation cycle (V1), immediately after the completion of the three-week rehabilitation program (V2), and eight weeks later (V3) (see Figure 1). The CANTAB scores will be determined using the software. The CANTAB test offers a variety of measures for monitoring cognitive functioning in patients with schizophrenia. The test comes with the CANTAB Connect Research: Admin Application User Guide, which provides information on whether higher scores indicate better ("+ve") or worse ("-ve") performance, or if the interpretation of a measure is more complex ("cx").
From enrollment to the end of treatment at 8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Lodz

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 1, 2023

Primary Completion (Estimated)

December 3, 2026

Study Completion (Estimated)

December 3, 2027

Study Registration Dates

First Submitted

November 25, 2025

First Submitted That Met QC Criteria

December 8, 2025

First Posted (Estimated)

December 9, 2025

Study Record Updates

Last Update Posted (Actual)

January 13, 2026

Last Update Submitted That Met QC Criteria

January 12, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AdriannaSzczakowska-02

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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