The present study will use transcranial electrical stimulation (tES) which are transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) combined with conventional physical therapy and cognitive-motor dual task gait training in sub-acute (at least 2 weeks after stroke onset) to chronic (within 5 years post-stroke) to investigate the effect on cortical activity, spinal motoneuron excitability, cognition and motor performance. The findings may enhance the evidence to support usages of tES for improvimg cognition, motor performance as well as cortical activity and spinal motoneuron excitability in a clinical setting.
Stroke is a sudden neurological event which is leading cause of death and disability. An impaired blood flow and oxygen supply leading to neuronal cell death follwoing stroke. In addition, an electroencephalography demonstrated a decrease of high frequency power bands (alpha and beta) and increase of low frequency bands (theta and delta). An increase in delta frequency is negatively correlated with cognition, while an increase in high-frequency bands are correlatedw ith an improvement of motor recovery and cognition. Furthermore, functional near-infrared spectroscopy (fNIRS) which is a non-invasive neuroimaging can monitors improvements in cortical activity throughchanges in cerebral blood flow and oxygen consumptions. Follwoing stroke, an alterations of cortical activity between ipsileasional hemisphere and contralesion hemisphere affect the spinal lelvel as it leads to increase spinal motoneuron excitability. An increase of spinal motoneuron excitability is likely due to abnormal control from cortex to spinal cord via descending pathway. Furthermore, hyperexcitability of spinal motoneuron is associated with post-stroke spasticity. However, the excat mechanisms of spasticity in post stroke remians unclear. Potential causes include imbalance in descending pathway regulation, abnormal intraspinal processing, and altered muscular viscoelasticity. Changes in spinal motoneuron excitability can be assessed using Hoffmann's reflex (H-reflex). Motor imapirments following stroke affects activities of daily living (ADLs), moreover cognitive impairements is commonly obsrved in post-stroke individuals that may limits motor and functional recovery and limits effectiveness of rehabilitation. These impairments affect both single- and duals-task activities, especially walking performance and increasing risk of falls in stroke individuals. In recent years, combining bottom-up and top-down approaches has been greater potential in promoting neural plasticity and enhancing motor recovery compared to single approach. Bottom-up approaches refers to rehabilitation that act on physical level and expected chnages in nervous system level, while top-down approach induce change in cortical level to induce change in motor function or physical level. The non-invasive brain stimulation (NIBS) is a top-down approach that enhance neural plasticity and mediated motor-relearning in neurological conditions. Transcranial electrical stimulation (tES) is one of NIBS which the most coom tES techniques are transcranial direct current stimulation (tDCS) and transcranial alternating currnt stimulation (tACS). Both tDCS and tACS are different in their wave forms. tDCS delivers a weak direct current with polartiy-specific effects, while tACS enhance neural plasticity and endogenous brain wave with frequency-specific. A recent review demonstrated the effectiveness of tDCS in improvement of motor function, functional abilities and cognitive function. Furthermore, a previous study demonstrated an improvement in cognitive function and ADLs following combining 2mA of tDCS with CMDT training. However, the amount of evidence on the effects of tACS is much less than that for tDCS, as it has only recently started to gain interest. The frequency used in tACS study mainly follows the association of brain wave and function. A previous review showed that gamma tACS enhance cognitive performance, working memory and logical thinking. In healthy population, a previous study demonstrated that applied gamma-tACS over M1 significantly improved velocity and acceleration of visuomotor task; nevertheless, this improvement did not found in beta-tACS. To provide evidence of the effects of tACS in the stroke population and to identify which type of transcranial electrical stimulation is most appropriate for stroke rehabilitation, a comparison between tDCS and tACS is necessary. Both tES technique will be combined with conventional physical therapy for 12 sessions (3 days/week for 4 weeks). tES will be provided for 20 minutes, then followed by convention physical therapy (1-hour) and cognitive-motor dual-task gait training (30-minute). Cortical activity will be assessed by EEG and fNIRS. Absoule spectral power of each frequency bands (alpha, beta, delta, and theta) will be analyze. The hemodynamics data will be analyze to represent changes of blood flow to the brain after intervention. The Hmax/Mmax ratio from flexor carpi radialis and soleus will be recorded to represent changes in spinal motoneuron excitability. The Fugl-Meyer assessment of upper and lower extremity and Timed up and go will be used to represent clinical outcomes of motor function and performance. The ERP recorded during Stroop color and word test and 2-Back test will be assessed together with the Montreal Cognitive Assessment (MoCA) in Thai version. Furthermore, behavoral data i.e. response time, accuracy will be collected to analyse to represent cogniton. For walking performance, dual-task interference or dual-task costs will be employed from dual-task walking. All outcomes will be assessed at baseline, post-intervention, 1-month follow-up, and 3-month follow-up.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
60
Electrode placement based on the international 10-20 electroencephalography electrode system. The electrode will be place over ipsilesional hemisphere on the primary motor cortex area. Anodal electrode will be placed over C3 or C4, while other 4 return electrodes will be placed over FC1/FC2, FC5/FC6, CP1/CP2, CP5/CP6. Participants will be asked to sit comfortably during stimulation. Participants will receive active HD-tDCS with intensity 2.0 mA for 20 minutes with 30-sec ramp-up and ramp-down.
Electrode placement based on the international 10-20 electroencephalography electrode system. The electrode will be place over ipsilesional hemisphere on the primary motor cortex area. Anodal electrode will be placed over C3 or C4, while other 4 return electrodes will be placed over FC1/FC2, FC5/FC6, CP1/CP2, CP5/CP6. Participants will be asked to sit comfortably during stimulation. Participants will receive active HD-tACS with intensity 2.0 mA for 20 minutes with frequency 70 Hz.
Electrode placement based on the international 10-20 electroencephalography electrode system. The electrode will be place over ipsilesional hemisphere on the primary motor cortex area. Anodal electrode will be placed over C3 or C4, while other 4 return electrodes will be placed over FC1/FC2, FC5/FC6, CP1/CP2, CP5/CP6. Participants will be asked to sit comfortably during stimulation. Participants will receive active HD-tDCS with intensity 2.0 mA for 20 minutes with electrical current flows 1-minute, with 30-second ramp-up and ramp-down, and no electrical current flow after first 1 minute to the end of stimulation.
Participants will be trained in cognitive-motor dual task gait training by using Zebris Rehawalk gait analysis and gait training. Participants will be asked to walk on treadmill while response to cognitive tasks on the computer screen, which is placed in front of participants. Treadmill speed will be set according to participants' preferred speed. Cognitive tasks involve color tasks and math tasks.
Conventional physical therapy starts immediately after stimulation ends. In 1-hour of conventional physical therapy involving 10 minutes of upper and lower extremity stretching, 20 minutes of upper extremity training, and 30 minutes of lower extremity training.
Faculty of Physical Therapy, Mahidol University
Nakhon Pathom, Thailand
RECRUITINGAbsolute power
The raw data from electroencephalographyt (EEG) in 5-min of eye-open and eye-close conditions converted to the power distribution of brain waves in different frequencies (i.e. delta, theta, and beta) usign a Fast Fourier Transformation (FFT)
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Blood oxygenation level
Changes in concentration of hemoglobin between oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (HbR) in the brain, which can indicate brain function in different areas are assessed by Functional Near-Infrared Spectroscopy (fNIRS)
Time frame: Baseline, 1-day post-intervention, 1-moth follow-up and 3-month follow-up
Event Related Potential (ERP)
ERP is a non-invasive measurement tool that detects a very small voltage generated by brain activity in response to a specific event (i.e. Stroop test, N-back test). This is a signal averaging form of EEG that detects signals starting from the onset of a stimulus to evaluate brain responses over time, those occurring at 200 milliseconds (P200), or 300 milliseconds (P300) .
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Fugl-Meyer assessment (FMA) of upper and lower extremities
The FMA is a clinical assessment that quantified level of motor impairement and evaluate recovery in post-stroke. The FMA Includes 33 items for the upper extremity and 17 items for the lower extremity, totaling 100 points. Higher scores indicate better motor performance.
Time frame: Baseline, 1-day post-intervention, 1-month follow-up, and 3-month follow-up
Montreal Cognitive Assessment
The Montreal Cognitive Assessment (MoCA) is used to assess cognitive functioning in eight domains: Visuospatial and executive function, Naming, Attention, Language, Abstraction, Delayed recall, Orientation, Short-term memory. Participants are instructed to complete both paper-based and verbal question-answering activities, such as drawing pictures, sorting numbers, naming animals, and reviewing vocabulary. The maximum total score is 30 points, with a high score indicating a good level of cognitive.
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Timed up and go test
Participants wear regular footware and if they have normally used gait aid, it is allowed to use in the test. The test measures the time taken when the participants stand up from the chair, walk at normal pace for 3 meters, turn around, walk back for 3 meters, and then sit on a chair.
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Cognitive-motor interference (CMI)
CMI refers to a decline in performance observed when a person simultaneously performs a cognitive and motor task, compared to performing a single- or dual-task separately. Managing both tasks requires divided attention, and interference arises when these cognitive resources are insufficient to maintain performance in both domains. The CMI can be quantified by the dual-task cost (DTC). The DTC is calculated by comparing the performance difference between single-task and dual-task conditions. Participants will be asked to perform 2 walking conditions on the treadmill (Zebris Rehawalk gait analysis and gait training). The walking conditions are single-walking and cognitive-motor dual task walking (CMDT walking). For single-walking, participants will be asked to walk at their preferred speed. For CMDT walking, participants will walk and response to stimuli on the screen simultaneously. During the test, stride length, step length, cadence and accuracy of response
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Soleus H-reflex
The H-reflex is an electrophysiological measurement used to assess spinal excitability. For the soleus H-reflex , participants will be in prone position with ankle in neutral position. A bipolar electrode will be placed over the popliteal fossa, and the surface EMG electrode will be attached to the motor point of the soleus muscle (two electrodes on the lower 1/3 of the lower leg), and the lateral malleolus (ground electrode). The electrical stimulation starts at a minimal intensity, increasing until an H-reflex response is detected, continuing to supramaximal intensity to elicit an M-wave. H-reflex latency, maximum H- and M-wave responses will be recorded. The Hmax/Mmax ratio will be calculated from maximum H- and M-wave amplitude responses.
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
Flexor carpi radialis (FCR) H-reflexe
For the FCR H-reflex, participants will sit with their wrist in neutral, forearm mid-pronated, and their elbow flexed at 45 degrees, with slight shoulder abduction, flexion, and neutral rotation (68). Bipolar electrode will be placed medially to cubital fossa and the biceps brachii tendon. Two surface electrodes will be positioned over the FCR (1/3 of the distance from the medial epicondyle to the radial styloid), with a grounded electrode placed over radial styloid process. For the FCR H-reflex (Figure 10), participants will sit with their wrist in neutral, forearm mid-pronated, and their elbow flexed at 45 degrees, with slight shoulder abduction, flexion, and neutral rotation (68). Bipolar electrode will be placed medially to cubital fossa and the biceps brachii tendon. Two surface electrodes will be positioned over the FCR (1/3 of the distance from the medial epicondyle to the radial styloid) (69), with a grounded electrode placed over radial styloid process.
Time frame: Baseline, 1-day post-intervention, 1-month follow-up and 3-month follow-up
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