Stroke
Conditions
Keywords
Stroke, Hand motor impairment, Transcranial alternating current stimulation, Non-invasive brain stimulation, motor learning, sensorimotor cortex, crossfrequency coupling, theta-gamma phase amplitude coupling
Brief summary
Hand motor function is often severely affected in stroke patients and its recovery is one primary goal in stroke rehabilitative treatment programs. Recently, theta-gamma transcranial alternating current stimulation (tACS) has been shown to enhance motor skill acquisition in healthy individuals. The aim of the present study is to examine the effect of theta-gamma tACS on motor skill acquisition in chronic stroke patients.
Detailed description
Hand motor function is often severely affected in stroke patients and recovery of function is a primary goal in stroke rehabilitative treatment programs. Recently, theta-gamma tACS has been shown to enhance motor skill acquisition in healthy individuals \[Akkad et al.2021\]. The aim of the present study is to examine the effect of theta-gamma tACS on motor skill acquisition in chronic stroke patients. In a randomized, controlled, triple-blind trial, chronic stroke patients with an initially impaired hand motor function will receive either (i) theta-gamma peak stimulation (TGP) or (ii) sham stimulation. TGP stimulation significantly improved motor learning in the study by Akkad et al (2021) compared to sham stimulation. tACS will be delivered through a five-electrode montage centered over the sensorimotor cortex on the lesioned side of the brain for approximately 38 min. During stimulation patients will perform a motor skill acquisition task performed with the affected hand. The task consists of short repetitive trials in which participants alternately press two buttons with their thumb. It is designed in a way that participants can improve their performance, more precisely the speed of button presses, and are encouraged to do so. To reduce skin sensations beneath the stimulation electrodes and thereby improve blinding compared to sham stimulation, a local anesthetic consisting of lidocaine and prilocaine will be administered underneath the stimulation electrodes. Based on the results of the study by Akkad et al. (2021) and on the assumption that theta-gamma phase amplitude coupling is a key mechanism for motor skill acquisition, the investigators hypothesize that motor skill acquisition will differ significantly between the TGP and sham group.
Interventions
DEVICETGP-tACS
38 min and 20s of 4mA peak-to-peak theta-gamma stimulation with 75 Hz-gamma coupled to the peak of 6Hz-theta waves. 3s ramp-up at the beginning of stimulation and 3s ramp-down at the end of stimulation. Administered using a Starstim® device and 5 gel electrodes with a πcm² area.
DEVICESham-tACS
38 min and 20s of alternation between 10s of 4mA peak-to-peak TGP- tACS and a 6 min 30s stimulation-free interval. Each stimulation consists of 3s ramp-up, 4s TGP stimulation and 3s ramp-down. Administered using a Starstim® device and 5 gel electrodes with a πcm² area.
Sponsors
Technical University of Twente
University of Oxford
Universitätsklinikum Hamburg-Eppendorf
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* German-speaking * ability to perform a thumb movement task with the affected hand * first-ever clinical ischemic stroke in the chronic phase * persistent mild motor deficit of the upper extremity or motor deficit of the upper extremity in the acute phase over \>24h
Exclusion criteria
* pronounced cognitive deficits * history of major neurological or psychiatric illness other than stroke * epilepsy or epileptic seizure in the history * any devices or implants in the head region (e.g. cochlear implant, aneurysm clips), * implanted pacemaker or medical pumps * intake of psychotropic medication * allergy to any ingredient of the local anesthetic cream * pregnancy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Motor Skill Acquisition | Over the course of the motor task with a duration of 38 minutes and 20 seconds. | Quotient of mean Duration of Button Presses of the best block and the baseline block. Best block is defined as the block with the lowest mean Duration of Button Presses. Duration of Button Press is the Duration between the first and fourth button press of a valid trial. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Duration of Button Presses | Baseline (consisting of 20 trials) and each of 6 blocks (consisting of 40 trials each) | Time span from first to last button press of a trial. Averaged for all trials of one block |
Other
| Measure | Time frame | Description |
|---|---|---|
| Thumb Speed and Thumb Acceleration | Over the course of the motor task with a duration of 38 minutes and 20 seconds. | An accelerometer will be fixed to the medial distal phalanx of the thumb. It measures the thumb acceleration in all three dimensions of space. We will use the accelerometer data for post-hoc explorative analysis. |
Countries
Germany
Outcome results
None listed