StrokeNCT06809959
Bifocal Transcranial Alternating Current Stimulation Targeting the Frontoparietal Network in Stroke Patients
A study testing In-phase-tACS and Out-of-phase-tACS in people with Stroke and Hand Functions, run by Universitätsklinikum Hamburg-Eppendorf at 1 site in Germany.
Trial summary
Hand and arm function is often significantly impaired in stroke patients, making its recovery a primary goal in rehabilitative treatment. This study investigates the effects of bifocal transcranial alternating current stimulation (tACS) on the frontoparietal network in stroke patients during the subacute to chronic… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Stroke, Hand Functions, Cerebrovascular Disease
- What is being tested?
- In-phase-tACS and Out-of-phase-tACS
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- 1 siteGermany
- Study dates
- 3 Feb 2025to 11 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
- First-ever clinical stroke
- Signed informed consent
- First-ever clinical ischemic stroke at least 3 months ago
- Stimulation areas (PMv and IPS) are unaffected
- Residual deficits in the upper limb
Who cannot join
- Presence of additional neurological or psychiatric disorders
- Use of psychotropic medication
- Pregnancy or potential pregnancy in female participants
- Pacemakers, other stimulators, or medication pumps
- Claustrophobia
- Non-MRI-compatible metallic implants or foreign objects in the body
- Contraindications for transcranial alternating current stimulation (e.g., epilepsy, history of seizures, any type of pacemaker)
Trial locations and contacts
1 site in 1 country.
Germany1 site
Department of Neurology, University Medical Center Hamburg-Eppendorf
Hamburg, 20246
About this study
Official title: Bifocal Transcranial Alternating Current Stimulation Targeting the Frontoparietal Network in Stroke Patients to Enhance Network Connectivity
Hand and arm function is often significantly impaired in stroke patients, making its recovery a primary goal in rehabilitative treatment. This study investigates the effects of bifocal transcranial alternating current stimulation (tACS) on the frontoparietal network in stroke patients during the subacute to chronic recovery phase. By using non-invasive brain stimulation, the study aims to modulate the neural network connectivity between the ipsilesional parietal and premotor cortices. Electroencephalography and kinematic data will be utilized to assess the impact of tACS on functional connectivity and its subsequent effect on motor function. The ultimate goal is to enhance functional coupling within these networks to promote motor function in stroke patients.
Read the detailed description
Hand and arm function is often significantly impaired in stroke patients, making recovery of these functions a primary goal in stroke rehabilitation. Despite advances in acute stroke thera-pies, more than 50% of stroke survivors continue to experience motor deficits, particularly in hand and arm function, which negatively impacts their quality of life. The integrity of neural networks, especially the frontoparietal network, plays a central role in motor control, and has been shown to be altered after stroke. Transcranial alternating current stimulation (tACS) offers a promis-ing approach to modulate these brain network connections, potentially influencing motor func-tion in stroke patients.
In a randomized, controlled, triple-blind, crossover design, this study investigates the effects of 24Hz bifocal tACS on functional connectivity between the ipsilesional anterior intraparietal sulcus (aIPS) and ventral premotor cortex (PMv) in stroke patients during the subacute to chronic recovery phase. Each patient will receive three types of stimulation-(i) in-phase tACS, (ii) out-of-phase tACS, and (iii) sham stimulation-in a randomized order, with a one-week washout pe-riod between sessions to avoid carryover effects. During in-phase tACS, 24Hz stimulation over aIPS and PMv will be in phase; during out-of-phase stimulation, the phase across sights will vary by 180 degrees.
Bifocal tACS will be delivered using two four-electrode montages centered over the aIPS and PMv of the lesioned hemisphere for approximately 21 minutes per session. During each session, patients will perform a Reach-to-Grasp (RTG) task three times: before stimulation, during stimu-lation, and after stimulation. Patients will perform both a pinch grip and a whole-hand grasp during the RTG task. EEG data will be collected pre- and post-stimulation, while kinematic meas-urements will also be recorded during the stimulation task. To minimize skin sensations under the electrodes and improve blinding, a local anesthetic consisting of lidocaine and prilocaine will be applied prior to electrode placement. Clinical assessments as well as structural and func-tional imaging will be obtained to characterize each patient.
The investigators hypothesize that 24Hz bifocal tACS on the frontoparietal network alters its connectivity compared to sham stimulation.
This study seeks to enhance the understanding of functional coupling within the frontoparietal network, aiming to establish bifocal tACS as a targeted and innovative therapy to improve motor function in stroke patients.
- Conditions
- Stroke, Hand Functions, Cerebrovascular Disease, Brain Diseases
- Being tested
- In-phase-tACS, Out-of-phase-tACS, Sham -tACS
- Keywords
- Stroke, Hand motor impairment, transcranial alternating current stimulation, non-invasive brain stimulation, reach-to-grasp, functional connectivity, frontoparietal network, beta oscillations, kinematic, eeg
- Medical subject headings
- Stroke, Cerebrovascular Disorders, Brain Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
In-phase-tACSDevice
21 minutes and 30 seconds of bifocal stimulation at 3 mA peak-to-peak per field, targeting the aIPS and PMv of the lesioned hemisphere. The stimulation is delivered at 24 Hz with the waveforms of both fields aligned in phase. A 10-second ramp-up at the beginning and a 10-second ramp-down at the end are included to ensure participant comfort. The protocol is administered using the Starstim® device with gel-based electrodes, each with a π cm² surface area.
Out-of-phase-tACSDevice
21 minutes and 30 seconds of bifocal stimulation at 3 mA peak-to-peak per field over the aIPS and PMv of the lesioned hemisphere at 24 Hz. In this condition, the waveforms of the two fields are shifted by 180°, creating an out-of-phase stimulation pattern. A 10-second ramp-up and ramp-down are included, and the protocol is administered using the Starstim® device with gel-based electrodes, each with a π cm² surface area.
Sham -tACSDevice
21 minutes and 30 seconds of stimulation mimicking the setup of active tACS, with an initial 10-second ramp-up followed by a 10-second ramp-down. The remainder of the session is stimulation-free. This protocol is administered using the Starstim® device and gel-based electrodes with a π cm² surface area, maintaining the same setup as the active conditions to ensure comparability.
| Study group | Role | What they receive |
|---|---|---|
| In-phase-tACS | Active comparator | Patients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. Receives: Device: In-phase-tACS |
| Out-of-phase-tACS | Active comparator | Patients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. Receives: Device: Out-of-phase-tACS |
| Sham -tACS | Sham comparator | Patients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. Receives: Device: Sham -tACS |
What is being measured
The primary outcome is the main question the study is designed to answer.
Connectivity in the frontoparietal network
Changes in beta-band functional connectivity between aIPS and PMv during the reach-to -grasp task obtained from EEG recording prior and after each session will be evaluated, and compared across stimulation types (in-phase, out-of-phase, and sham).
Measured: Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.
Secondary outcomes (2)
Motor Task Performance
Motor task performance will be assessed through kinematic data collected during the Reach-to-Grasp task. An exploratory kinematic analysis will investigate whether tACS stimulation enhances motor task performance compared to sham stimulation. These effects will be analyzed both within sessions and across stimulation conditions (in-phase, out-of-phase, and sham) to identify stimulation-specific influences on motor performance.
Measured: Three 21-minute-and-30-second measurements (before, during, and after tACS) will be conducted across three sessions for each tACS condition (in-phase, out-of-phase, and sham) with one-week intervals between sessions.
Beta power in the frontoparietal network
Changes in beta-band power over aIPS and PMv during the reach-to -grasp task obtained from EEG recording prior and after each session will be evaluated, and compared across stimulation types (in-phase, out-of-phase, and sham).
Measured: Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Feb 2025
- Study start3 Feb 2025
- Primary completion11 Apr 2026
- Study completion11 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Participants will receive all three types of stimulation-(i) in-phase tACS, (ii) out-of-phase tACS, and (iii) sham stimulation-on separate days in a randomized order. Each session will be separated by a one-week washout period to prevent carryover effects.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universitätsklinikum Hamburg-Eppendorf
- Sponsor type
- University, hospital or other
- Collaborators
- Technical University of Twente
- Responsible party
- Principal investigator, Fanny Quandt, Universitätsklinikum Hamburg-Eppendorf
- Investigators
- Fanny Quandt, Dr. med., Principal investigator, Deparment of Neurology, University Medical Center Hamburg-EppendorfRobert Schulz, PD Dr. med., Principal investigator, Deparment of Neurology, University Medical Center Hamburg-Eppendorf
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06809959
- Sponsor's protocol ID
- biTACS
- Status last verified
- May 2026
- First submitted
- 30 Jan 2025
- Last updated
- 15 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bifocal Transcranial Alternating Current Stimulation Targeting the Frontoparietal Network in Stroke Patients to Enhance Network Connectivity
- ClinicalTrials.gov ID
- NCT06809959
- Acronym / sponsor ID
- biTACS
- Conditions
- Stroke, Hand Functions, Cerebrovascular Disease, Brain Diseases
- Keywords
- Stroke, Hand motor impairment, transcranial alternating current stimulation, non-invasive brain stimulation, reach-to-grasp, functional connectivity, frontoparietal network, beta oscillations
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Universitätsklinikum Hamburg-EppendorfUniversity, hospital or other
- Collaborators
- Technical University of Twente
- Study start
- 3 Feb 2025 (actual)
- Primary completion
- 11 Apr 2026 (actual)
- Study completion
- 11 Apr 2026 (actual)
- First posted
- 5 Feb 2025 (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.
Hand and arm function is often significantly impaired in stroke patients, making its recovery a primary goal in rehabilitative treatment. This study investigates the effects of bifocal transcranial alternating current stimulation (tACS) on the frontoparietal network in stroke patients during the subacute to chronic recovery phase. By using non-invasive brain stimulation, the study aims to modulate the neural network connectivity between the ipsilesional parietal and premotor cortices. Electroencephalography and kinematic data will be utilized to assess the impact of tACS on functional connectivity and its subsequent effect on motor function. The ultimate goal is to enhance functional coupling within these networks to promote motor function in stroke patients.
Detailed description
Hand and arm function is often significantly impaired in stroke patients, making recovery of these functions a primary goal in stroke rehabilitation. Despite advances in acute stroke thera-pies, more than 50% of stroke survivors continue to experience motor deficits, particularly in hand and arm function, which negatively impacts their quality of life. The integrity of neural networks, especially the frontoparietal network, plays a central role in motor control, and has been shown to be altered after stroke. Transcranial alternating current stimulation (tACS) offers a promis-ing approach to modulate these brain network connections, potentially influencing motor func-tion in stroke patients.
In a randomized, controlled, triple-blind, crossover design, this study investigates the effects of 24Hz bifocal tACS on functional connectivity between the ipsilesional anterior intraparietal sulcus (aIPS) and ventral premotor cortex (PMv) in stroke patients during the subacute to chronic recovery phase. Each patient will receive three types of stimulation-(i) in-phase tACS, (ii) out-of-phase tACS, and (iii) sham stimulation-in a randomized order, with a one-week washout pe-riod between sessions to avoid carryover effects. During in-phase tACS, 24Hz stimulation over aIPS and PMv will be in phase; during out-of-phase stimulation, the phase across sights will vary by 180 degrees.
Bifocal tACS will be delivered using two four-electrode montages centered over the aIPS and PMv of the lesioned hemisphere for approximately 21 minutes per session. During each session, patients will perform a Reach-to-Grasp (RTG) task three times: before stimulation, during stimu-lation, and after stimulation. Patients will perform both a pinch grip and a whole-hand grasp during the RTG task. EEG data will be collected pre- and post-stimulation, while kinematic meas-urements will also be recorded during the stimulation task. To minimize skin sensations under the electrodes and improve blinding, a local anesthetic consisting of lidocaine and prilocaine will be applied prior to electrode placement. Clinical assessments as well as structural and func-tional imaging will be obtained to characterize each patient.
The investigators hypothesize that 24Hz bifocal tACS on the frontoparietal network alters its connectivity compared to sham stimulation.
This study seeks to enhance the understanding of functional coupling within the frontoparietal network, aiming to establish bifocal tACS as a targeted and innovative therapy to improve motor function in stroke patients.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- Participants will receive all three types of stimulation-(i) in-phase tACS, (ii) out-of-phase tACS, and (iii) sham stimulation-on separate days in a randomized order. Each session will be separated by a one-week washout period to prevent carryover effects.
| Arm | Type | Receives |
|---|---|---|
| In-phase-tACS | Active comparator | Device: In-phase-tACSPatients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. |
| Out-of-phase-tACS | Active comparator | Device: Out-of-phase-tACSPatients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. |
| Sham -tACS | Sham comparator | Device: Sham -tACSPatients will perform a reach-to-grasp task with their affected hand during bifocal tACS targeting the aIPS and PMv of the lesioned hemisphere during three seperat sessions. The sequence of stimulation types will be randomized. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- First-ever clinical stroke
- Signed informed consent
- First-ever clinical ischemic stroke at least 3 months ago
- Stimulation areas (PMv and IPS) are unaffected
- Residual deficits in the upper limb
Key exclusion criteria (7 listed)
- Presence of additional neurological or psychiatric disorders
- Use of psychotropic medication
- Pregnancy or potential pregnancy in female participants
- Pacemakers, other stimulators, or medication pumps
- Claustrophobia
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 |
|---|---|---|
| In-phase-tACS21 minutes and 30 seconds of bifocal stimulation at 3 mA peak-to-peak per field, targeting the aIPS and PMv of the lesioned hemisphere. The stimulation is delivered at 24 Hz with the waveforms of both fields aligned in phase. A 10-second ramp-up at the beginning and a 10-second ramp-down at the end are included to ensure participant comfort. The protocol is administered using the Starstim® device with gel-based electrodes, each with a π cm² surface area. | Device | In-phase-tACS |
| Out-of-phase-tACS21 minutes and 30 seconds of bifocal stimulation at 3 mA peak-to-peak per field over the aIPS and PMv of the lesioned hemisphere at 24 Hz. In this condition, the waveforms of the two fields are shifted by 180°, creating an out-of-phase stimulation pattern. A 10-second ramp-up and ramp-down are included, and the protocol is administered using the Starstim® device with gel-based electrodes, each with a π cm² surface area. | Device | Out-of-phase-tACS |
| Sham -tACS21 minutes and 30 seconds of stimulation mimicking the setup of active tACS, with an initial 10-second ramp-up followed by a 10-second ramp-down. The remainder of the session is stimulation-free. This protocol is administered using the Starstim® device and gel-based electrodes with a π cm² surface area, maintaining the same setup as the active conditions to ensure comparability. | Device | Sham -tACS |
Primary outcome
Connectivity in the frontoparietal network
Time frame: Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.
Changes in beta-band functional connectivity between aIPS and PMv during the reach-to -grasp task obtained from EEG recording prior and after each session will be evaluated, and compared across stimulation types (in-phase, out-of-phase, and sham).
2 secondary outcomes
Motor Task Performance
Time frame: Three 21-minute-and-30-second measurements (before, during, and after tACS) will be conducted across three sessions for each tACS condition (in-phase, out-of-phase, and sham) with one-week intervals between sessions.
Beta power in the frontoparietal network
Time frame: Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.
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 15 May 2026.
- Individual participant dataSharing planned: Undecided
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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.
Fanny Quandt, Dr. med. principal investigator
Deparment of Neurology, University Medical Center Hamburg-Eppendorf
Robert Schulz, PD Dr. med. principal investigator
Deparment of Neurology, University Medical Center Hamburg-Eppendorf
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing In-phase-tACS and Out-of-phase-tACS in people with Stroke and Hand Functions, run by Universitätsklinikum Hamburg-Eppendorf at 1 site in Germany.
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 5 inclusion and 7 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 15 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 Germany. 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?
Connectivity in the frontoparietal network (time frame: Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.). 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 15 May 2026; AzTrials last refreshed its copy on 26 Oct 2026.