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

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

Interventions

DEVICE

In-phase-tACS

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.

DEVICE

Out-of-phase-tACS

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.

DEVICE

Sham -tACS

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.

Sponsors & Collaborators

• Technical University of Twente

  collaborator OTHER

• Universitätsklinikum Hamburg-Eppendorf

  lead OTHER

Principal Investigators

• Fanny Quandt, Dr. med. · Deparment of Neurology, University Medical Center Hamburg-Eppendorf

• Robert Schulz, PD Dr. med. · Deparment of Neurology, University Medical Center Hamburg-Eppendorf

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-02-03

Primary Completion

2026-04-11

Completion

2026-04-11

Countries

• Germany

Study Locations