Bifocal Transcranial Alternating Current Stimulation Targeting the Frontoparietal Network in Stroke Patients

NCT06809959 | Recruiting

• 1 other identifier: biTACS
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief 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 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.

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; kinematic; eeg

Outcome Measures

Primary Outcomes (1)

• 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).

  Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.

Secondary Outcomes (2)

• Motor Task Performance

  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

  Prior and after stimulation, each recording lasting 21 minutes and 30 seconds.

Study Arms (3)

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.

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.

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.

Device: Sham -tACS

Interventions

In-phase-tACS DEVICE

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.

In-phase-tACS

Out-of-phase-tACS DEVICE

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.

Out-of-phase-tACS

Sham -tACS DEVICE

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.

Sham -tACS

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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)

Sponsors & Collaborators

• Universitätsklinikum Hamburg-Eppendorf: lead
• Technical University of Twente: collaborator

Study Sites (1)

Department of Neurology, University Medical Center Hamburg-Eppendorf

Hamburg, 20246, Germany

RECRUITING

MeSH Terms

Conditions

Stroke; Cerebrovascular Disorders; Brain Diseases

Condition Hierarchy (Ancestors)

Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases

Study Officials

• Fanny Quandt, Dr. med.

  Deparment of Neurology, University Medical Center Hamburg-Eppendorf

  PRINCIPAL INVESTIGATOR

• Robert Schulz, PD Dr. med.

  Deparment of Neurology, University Medical Center Hamburg-Eppendorf

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Fanny Quandt, Dr. med.

CONTACT

+4974100; f.quandt@uke.de

Robert Schulz, PD Dr. med.

CONTACT

+4974100; r.schulz@uke.de

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 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.

Study Record Dates

• First Submitted: January 30, 2025
• First Posted: February 5, 2025
• Study Start: February 3, 2025
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026
• Last Updated: February 13, 2025

Record last verified: 2025-02

Locations

DE (1)