Effects of Bihemispheric Transcranial Direct Current Stimulation on Motor Function in Stroke Patients

Effects of Bihemispheric Transcranial Direct Current Stimulation on Motor Function in Stroke Patients

The Effect of Bihemispheric Transcranial Direct Current Stimulation Therapy on Upper Extremity Motor Functions in Stroke Patients

Motor impairment (impairment of movement) due to stroke is one of the leading disabilities in adults. In addition to established means of facilitating motor recovery after stroke such as physical and occupational therapy, a variety of experimental rehabilitation approaches have been tested. Although there have been significant advances in stroke rehabilitation with these techniques and treatments, research on this subject is continuing. Recent studies have focused on non-invasive brain stimulation techniques. Transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) therapies, which are methods of non-invasive brain stimulation that may be effective on cerebral remodelling, aim to reestablish the disturbed balance between the anatomic areas of the brain seen in stroke patients. The primary aim of this study is to evaluate the effectiveness of bihemispheric transcranial direct current stimulation (tDCS) applications on the upper extremity motor functions of patients with stroke.

Motor impairment due to ischemic and hemorrhagic stroke is one of the leading disabilities in adults. In addition to established means of facilitating motor recovery after stroke such as physical and occupational therapy, a variety of experimental rehabilitation approaches have been tested. Recent developments include noninvasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). The use of these tools is based on neurophysiologic studies demonstrating an imbalance of interhemispheric interactions which appears to interfere with the recovery process. The model of interhemispheric imbalance provides a framework for developing hypotheses based on its 2 facets: 1) upregulating excitability of intact portions of the ipsilesional motor cortex and 2) downregulating excitability of the contralesional motor cortex to modulate its unrestrained inhibitory influence on ipsilesional regions. Studies to date have shown have shown the beneficial effects of tDCS on motor skills and motor learning. Bihemispheric tDCS may potentiate the effects of anodal stimulation to the lesional hemisphere through additional modulation of interhemispheric interactions via cathodal stimulation to the contralesional motor cortex. The primary aim of this prospective, randomized, sham controlled study is to evaluate the effectiveness of bihemispheric transcranial direct current stimulation (tDCS) applications on the upper extremity motor functions of patients with stroke.

The aim of the study is to evaluate and compare the effect of tDCS plus conventional physiotherapy and occupational therapy to sham tDCS plus conventional physiotherapy and occupational therapy on upper extremity motor function in patients with subacute stroke was aimed in our study. 32 patients will be randomly assigned to one of two groups in parallel for the duration of the study: bihemispheric tDCS (n:16), or sham tDCS (n:16). In addition to a conventional physiotherapy and occupational therapy program, bihemispheric tDCS application will be applied to one group and sham tDCS applied to the second group. A constant current stimulator(ZMI Electronics Limited,Taiwan,2012) will be used for the application of tDCS. In both groups, the tDCS application will be started simultaneously with the occupational therapy session and will last for thirty minutes.

Sixteen stroke patient receiving bihemispheric tDCS in addition to a conventional physiotherapy (PT) and occupational therapy (OT) program for five consecutive days per week for a three week period (a total of fifteen sessions). The one hour long conventional PT sessions will include an upper extremity range of motion, strengthening and neurofacilitation exercise program. The one hour long OT sessions will include task specific exercises chosen according to the patient's functional status, including activities aimed at improving gross and fine motor function of the upper extremities. The tDCS application will be applied at the beginning of each OT session and will be continued for a total of thirty minutes at 2 mA.

Sixteen stroke patient receiving a conventional PT and OT program and sham tDCS for 5 consecutive days per week for a 3 week period ( a total of 15 sessions). The one hour long conventional PT and OT sessions will be the same as in the tDCS group. For sham tDCS, electrode application and positioning will be the same as the intervention group and will be applied at the beginning of each OT session as previously described. The current will initially be increased up to 2 mA, so to provide the typical initial tingling sensation, and slowly decreased over 30 seconds and consequently switched off. The electrodes will be removed after a total of thirty minutes.

A constant current stimulator (ZMI Electronics LTD.,Taiwan,2012) will be used through 2 saline-soaked surface gel-sponge electrodes (22 cm2 active area). Real stimulation consisting of thirty minutes of 2 mA direct current with the anode placed over the ipsilesional and the cathode over the contralesional motor cortex (C3 and C4 of the international 10-20 EEG electrode system).

For sham tDCS, the same electrode positions were used. The current was ramped up to 2 mA and slowly decreased over 30 seconds to ensure the typical initial tingling sensation

The Fugl-Meyer Upper Extremity (FMUE) Scale is a widely used and highly recommended stroke-specific, performance-based measure of impairment. It is designed to assess reflex activity, movement control and muscle strength in the upper extremity of people with post-stroke hemiplegia. It has been extensively used as an outcome measure in rehabilitation trials and to record poststroke recovery, particularly in the USA. The FMUE Scale comprises 33 items, each scored on a scale of 0 to 2, where 0 = cannot perform, 1 = performs partially and 2 = performs fully. It is free, requires only household items for testing, and takes up to 30 minutes to administer.The total score ranges from 0-66 where 66. The higher the score the less the level of impairment.

Before treatment sessions begin and 1 week after fifteen treatment sessions have been completed (three weeks after the initial onset of treatment).

The Functional Independence Measure (FIM) is an 18-item seven level ordinal scale of physical, psychological and social function.The tool is used to assess a patient's level of functionality as well as change in patient status in response to rehabilitation or medical intervention. 13 of the 18 items of the FIM assess motor function and provide a 'motor score', the remaining five questions assess communication and social skills and provide a 'cognitive score' . Each item is scored from 1=complete dependence of task to 7=complete independence of task. The lowest possible attainable total score is 18 and the highest possible attainable total score is 126. The higher the score the higher the level of independence. When considering the subscores, the lowest possible attainable motor score is 13 and the highest is 91. The lowest possible attainable cognitive subscore is 5 and the highest is 35.

Before treatment sessions begins and 1 week after fifteen treatment sessions have been completed (three weeks after the initial onset of treatment)

The Brunnstrom Stages of Stroke Recovery is a test that evaluates the motor development of stroke patients. In 1966, Signe Brunnstrom identified the stages of motor development observed in a large number of hemiplegic patients. In this staging, the hemiplegic upper extremity, lower extremity and hand are evaluated separately and the motor development of these three areas are staged from 1-6. The lowest stage according to this staging system is stage 1 (flask, no movement); the highest stage is stage 6 (normal motor function). Higher Brunnstrom stages indicate better motor development.

Before treatment sessions begins and 1 week after fifteen treatment sessions have been completed (three weeks after the initial onset of treatment)

Inclusion Criteria: 18-75 years old, female or male Clinical evaluation consistent with hemiplegia First time stroke with brain computerized tomography (CT) and / or magnetic resonance imaging (MRI) findings consistent with stroke At least 3 months since stroke onset Presence of a stable medical condition Preserved cognitive function as determined by a mini mental state examination score of 23 and above Exclusion Criteria: Presence of a sensory aphasia Presence of neglect syndrome A history of epilepsy Presence of a pacemaker Previous history of stroke History of previous cranial surgery Presence of a brain tumour Presence of an intracranial metallic implant Marked hearing / visual impairment Presence of severe spasticity (grade 3-4 according to the modified Ashworth scale)

Individual participant data that underlie the results reported in this article, after identification (text, tables, figures and appendices) will be made available

The data will be shared with researchers providing a methodologically sound proposal Proposals should be directed to drdilekalisar@gmail.com. To gain access, data requestors will need to sign a data access agreement. Data will be accessible for a period of one year.

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