StrokeNCT05570578
Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming in Aphasic Patients.
A study testing HD-tDCS in people with Stroke and Aphasia, run by Adrian Guggisberg at 1 site in Switzerland.
Trial summary
High-Definition Transcranial Direct Current Stimulation (HD-tDCS) allows to induce, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of a given cerebral region and to obtain a very focused cortical effect. Read more about this study
- Who is it for?
- Ages 18 years and older
- What is being tested?
- HD-tDCS
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 14 participants
- Where
- 1 siteSwitzerland
- Study dates
- 24 Oct 2022to 1 Apr 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Ischemic or hemorrhagic stroke
- Presence of aphasia with difficulty finding words and/or naming objects/pictures
- ≥12 months post-stroke
- ≥ 18 years of age
- French-speaking
- Able to participate in 30-60 min therapeutic sessions (good concentration and understanding of the task and ability to follow instructions
Who cannot join
- Patients unable to understand the given information on the study and its objectives, or instructions for tasks performed.
- Impaired alertness or delirium
- Severe co-morbidity affecting speech
- Contraindication to tDCS: pregnant women, patients with active implants such as pacemakers or cochlear implants, patients with one or more seizures, metal objects in the brain
- Occurrence of a new stroke during the study protocol.
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
Division of Neurorehabilitation, University Hospital of Geneva
Geneva, Canton of Geneva, 1211
About this study
Official title: Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming
High-Definition Transcranial Direct Current Stimulation (HD-tDCS) allows to induce, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of a given cerebral region and to obtain a very focused cortical effect. Previous studies using HD-tDCS have shown the effectiveness of this stimulation technique for enhancing language recovery in patients with aphasia.
However, language processes are not determined solely by local neural activity at a single site, but rather by the interaction between neural networks. This is because a large cortical network is involved in language processes and, therefore, the same language disorder may result from lesions at different locations in this network.
Read more
The investigators hypothesize that anodal HD-tDCS will enhance neural interactions between language areas and, thereby, improve language processing and word learning.
The investigators propose to carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
Read the detailed description
Functional connectivity (FC) represents a means of analyzing functional interactions in the brain network by assessing the statistical dependence of neural activity between brain areas. The brain maintains a high level of interactions between brain areas even in the resting state, when it is not explicitly involved in a specific task. Resting-state interactions occur mainly in the so-called alpha frequency band (8-13 Hz) . Moreover, these resting-state interactions are crucial for correct task performance and learning. Indeed, healthy subjects with high resting-state alpha-band FC levels are better able to perform tasks and learn. For example, subjects with high levels of FC between Broca's area and the rest of the brain perform better on language production tasks and show greater training gains when learning new words. In addition, patients with brain damage due to stroke show a reduction in resting-state alpha-band FC, which correlates with the severity of neurological deficits. In particular, a loss of FC of structurally preserved inferior frontal areas was associated with more severe aphasia. Conversely, high-levels of FC between the inferior frontal brain areas and the rest of the brain during the first weeks after stroke was associated with better recovery from aphasia, probably reflecting a reorganization of neural connections as a neural mechanism involved in plasticity. Resting-state FC is therefore an interesting neural target for therapy, which could help improve recovery from aphasia.
In a previous study on healthy subjects, the investigators have indeed observed that HD-tDCS applied to Broca's area improves the ability for new-verb learning, i.e., the correct naming of action pictures. This improvement in learning correlated with greater increase in FC between Broca's and Wernicke's area.
The investigators now carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
- Being tested
- HD-tDCS
- Keywords
- tDCS, Functional connectivity, EEG
- Medical subject headings
- Stroke, Aphasia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HD-tDCSDevice
Also called high-density transcranial direct current stimulation, DC-stimulator
The anode electrode will be placed over Broca's area, 4 cathode electrodes will be placed at about 2 cm distance each from the anode in 4 directions.
| Study group | Role | What they receive |
|---|---|---|
| HD-tDCS | Active comparator | high-density transcranial direct current stimulation (HD-tDCS) over Broca's area Receives: Device: HD-tDCS |
| sham-tDCS | Sham comparator | sham transcranial direct current stimulation. The same setup will be used as in the HD-tDCS arm, except that the current will be ramped up for 30 seconds and then switched off. This does not lead to neural effects, but the patients have a similar sensation. Receives: Device: HD-tDCS |
What is being measured
The primary outcome is the main question the study is designed to answer.
Action picture naming, short-term improvement
Change in number of correctly named action pictures
Measured: Change from day 1 (baseline) to day 5 (posttest)
Secondary outcomes (1)
Functional connectivity between Broca's and Wernicke's area
Change in the normalized imaginary component of coherence between Broca and Wernicke
Measured: Change from day 1 (baseline) to day 5 (posttest)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Oct 2022
- Study start24 Oct 2022
- Primary completion1 Feb 2026
- Study completion1 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StrokeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- Adrian Guggisberg
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Adrian Guggisberg, University Hospital, Geneva
- Investigators
- Adrian G Guggisberg, MD, Principal investigator, University of Geneva, Switzerland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05570578
- Sponsor's protocol ID
- 2022-D0058
- Status last verified
- Apr 2026
- First submitted
- 4 Oct 2022
- Last updated
- 4 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Published and analyzed data will be archived in a secure location on a data sharing server that meets the FAIR (Findability, Accessibility, Interoperability, and Reuse) principles for a minimum of 10 years.
Study at a glance
From the registry record, last updated by the sponsor on 4 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming
- ClinicalTrials.gov ID
- NCT05570578
- Acronym / sponsor ID
- 2022-D0058
- Keywords
- tDCS, Functional connectivity, EEG
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- Adrian GuggisbergUniversity, hospital or other
- Study start
- 24 Oct 2022 (actual)
- Primary completion
- 1 Feb 2026 (actual)
- Study completion
- 1 Apr 2026 (actual)
- First posted
- 6 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
High-Definition Transcranial Direct Current Stimulation (HD-tDCS) allows to induce, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of a given cerebral region and to obtain a very focused cortical effect. Previous studies using HD-tDCS have shown the effectiveness of this stimulation technique for enhancing language recovery in patients with aphasia.
However, language processes are not determined solely by local neural activity at a single site, but rather by the interaction between neural networks. This is because a large cortical network is involved in language processes and, therefore, the same language disorder may result from lesions at different locations in this network.
The investigators hypothesize that anodal HD-tDCS will enhance neural interactions between language areas and, thereby, improve language processing and word learning.
The investigators propose to carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
Detailed description
Functional connectivity (FC) represents a means of analyzing functional interactions in the brain network by assessing the statistical dependence of neural activity between brain areas. The brain maintains a high level of interactions between brain areas even in the resting state, when it is not explicitly involved in a specific task. Resting-state interactions occur mainly in the so-called alpha frequency band (8-13 Hz) . Moreover, these resting-state interactions are crucial for correct task performance and learning. Indeed, healthy subjects with high resting-state alpha-band FC levels are better able to perform tasks and learn. For example, subjects with high levels of FC between Broca's area and the rest of the brain perform better on language production tasks and show greater training gains when learning new words. In addition, patients with brain damage due to stroke show a reduction in resting-state alpha-band FC, which correlates with the severity of neurological deficits. In particular, a loss of FC of structurally preserved inferior frontal areas was associated with more severe aphasia. Conversely, high-levels of FC between the inferior frontal brain areas and the rest of the brain during the first weeks after stroke was associated with better recovery from aphasia, probably reflecting a reorganization of neural connections as a neural mechanism involved in plasticity. Resting-state FC is therefore an interesting neural target for therapy, which could help improve recovery from aphasia.
In a previous study on healthy subjects, the investigators have indeed observed that HD-tDCS applied to Broca's area improves the ability for new-verb learning, i.e., the correct naming of action pictures. This improvement in learning correlated with greater increase in FC between Broca's and Wernicke's area.
The investigators now carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HD-tDCS | Active comparator | Device: HD-tDCShigh-density transcranial direct current stimulation (HD-tDCS) over Broca's area |
| sham-tDCS | Sham comparator | Device: HD-tDCSsham transcranial direct current stimulation. The same setup will be used as in the HD-tDCS arm, except that the current will be ramped up for 30 seconds and then switched off. This does not lead to neural effects, but the patients have a similar sensation. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Ischemic or hemorrhagic stroke
- Presence of aphasia with difficulty finding words and/or naming objects/pictures
- ≥12 months post-stroke
- ≥ 18 years of age
- French-speaking
Key exclusion criteria (5 listed)
- Patients unable to understand the given information on the study and its objectives, or instructions for tasks performed.
- Impaired alertness or delirium
- Severe co-morbidity affecting speech
- Contraindication to tDCS: pregnant women, patients with active implants such as pacemakers or cochlear implants, patients with one or more seizures, metal objects in the brain
- Occurrence of a new stroke during the study protocol.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| HD-tDCSAlso: high-density transcranial direct current stimulation, DC-stimulatorThe anode electrode will be placed over Broca's area, 4 cathode electrodes will be placed at about 2 cm distance each from the anode in 4 directions. | Device | HD-tDCS, sham-tDCS |
Primary outcome
Action picture naming, short-term improvement
Time frame: Change from day 1 (baseline) to day 5 (posttest)
Change in number of correctly named action pictures
1 secondary outcome
Functional connectivity between Broca's and Wernicke's area
Time frame: Change from day 1 (baseline) to day 5 (posttest)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 May 2026.
- Individual participant dataSharing planned: Yes. Published and analyzed data will be archived in a secure location on a data sharing server that meets the FAIR (Findability, Accessibility, Interoperability, and Reuse) principles for a minimum of 10 years.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Adrian G Guggisberg, MD principal investigator
University of Geneva, Switzerland
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing HD-tDCS in people with Stroke and Aphasia, run by Adrian Guggisberg at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Action picture naming, short-term improvement (time frame: Change from day 1 (baseline) to day 5 (posttest)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 May 2026; AzTrials last refreshed its copy on 6 Nov 2026.