Investigation of Neuromodulatory Effect of Anodal Cerebellar Transcranial Direct Current Stimulation on the Primary Motor Cortex Using Functional Near-Infrared Spectroscopy.

Cerebellar brain inhibition (CBI), a neural connection between the cerebellum and primary motor cortex (M1), has been researched as a target pathway for neuromodulation to improve clinical outcomes in various neurological diseases. However, conflicting results of anodal cerebellar transcranial direct current stimulation (acb-tDCS) on M1 excitability indicate that additional investigation is required to examine its precise effect. This study aimed to gather evidence of the neuromodulatory effect of acb-tDCS on the M1 using functional near-infrared spectroscopy (fNIRS). Sixteen healthy participants were included in this cross-over study. Participants received real and sham acb-tDCS randomly, with a minimum 1-week washout period between them. The anode and cathode were placed on the right cerebellum and the right buccinator muscle, respectively. Stimulation lasted 20 min at an intensity of 2 mA, and fNIRS data were recorded for 42 min (including a 4-min baseline before stimulation and an 18-min post-stimulation duration) using eight channels attached bilaterally on the M1. acb-tDCS induced a significant decrease in oxyhemoglobin (HbO) concentration (inhibitory effect) in the left (contralateral) M1, whereas it induced a significant increase in HbO concentration (excitatory effect) in the right (ipsilateral) M1 compared to sham tDCS during (p < 0.05) and after stimulation (p < 0.01) in a group level analysis. At the individual level, variations in response to acb-tDCS were observed. Our findings demonstrate the neuromodulatory effects of acb-tDCS on the bilateral M1 in terms of neuronal hemodynamics.

White matter tracts involved in subcortical unilateral spatial neglect in subacute stroke.

Background: Unilateral spatial neglect (USN) is common and associated with poor motor and cognitive outcomes as well as impaired quality of life following stroke. Traditionally, the neural substrates underlying USN have been thought to be cortical areas, such as the posterior parietal cortex. However, patients with stroke involving only subcortical structures may also present with USN. While only a few studies have reported on USN in subcortical stroke, the involvement of white matter tracts related to brain networks of visuospatial attention is one possible explanation for subcortical neglect. Therefore, this study aimed to investigate which specific white matter tracts are neural substrates for USN in patients with subcortical stroke. Methods: Twenty-two patients with subcortical stroke without cortical involvement who were admitted to the Department of Rehabilitation Medicine at Seoul National University Bundang Hospital were retrospectively enrolled. Nine subjects were subclassified into a "USN(+)" group, as they had at least two positive results on three tests (the Schenkenberg line bisection test, Albert's test, and house drawing test) and a score of 1 or higher on the Catherine Bergego scale. The remaining 13 subjects without abnormalities on those tests were subclassified into the "USN(-)" group. Stroke lesions on MRI were manually drawn using MRIcron software. Lesion overlapping and atlas-based analyses of MRI images were conducted. The correlation was analyzed between the overlapped lesion volumes with white matter tracts and the severity of USN (in the Albert test and the Catherine Bergego scale). Results: Lesions were more widespread in the USN(+) group than in the USN(-) group, although their locations in the right hemisphere were similar. The atlas-based analyses identified that the right cingulum in the cingulate cortex, the temporal projection of the superior longitudinal fasciculus, and the forceps minor significantly overlapped with the lesions in the USN(+) group than in the USN(-) group. The score of the Catherine Bergego scale correlated with the volume of the involved white matter tracts. Conclusion: In this study, white matter tracts associated with USN were identified in patients with subcortical stroke without any cortical involvement. Our study results, along with previous findings on subcortical USN, support that USN may result from damage to white matter pathways.

Effects of anodal transcranial direct current stimulation over the contralesional hemisphere on motor recovery in subacute stroke patients with severe upper extremity hemiparesis: Study protocol for a randomized controlled trial.

INTRODUCTION: Upper extremity motor impairment is one of the major sequelae of stroke, resulting in limitations of activities of daily living. Recently, contralesional cortical activation has been reported to be important for motor recovery in stroke patients with severe upper extremity hemiparesis due to the extensive corticospinal tract involvement. We therefore designed this study to investigate the effects of contralesional anodal transcranial direct current stimulation (tDCS), which induces cortical activation, in stroke patients with severe upper extremity motor impairment. METHODS AND ANALYSIS: We will recruit patients with subacute stroke (<3 months after onset) with unilateral upper extremity weakness who meet the following criteria: Shoulder Abduction and Finger Extension (SAFE) score below 8, Fugl-Meyer Assessment for upper extremity (FMA-UE) score ≤25, and absent motor evoked potential (MEP) response on the affected extensor carpi radialis muscle. Subjects will be randomly allocated to either the intervention (n = 18) or the control group (n = 18). The intervention group will undergo 10 sessions of robotic arm rehabilitation with simultaneous anodal tDCS over the contralesional premotor area, whereas the control group will receive sham tDCS during the same sessions. One daily session consists of 25 minutes.The primary outcome measure of this study is the Fugl-Meyer Assessment score of the upper extremity; the secondary outcome measures are the Korean version of the Modified Barthel Index, the Brunnstrom stage of the affected arm and hand, the Box and Block Test, the Modified Ashworth Scale, the Manual Muscle Power Test, and the patient's encephalographic laterality index. DISCUSSION: Findings of this study will help to establish an individualized tDCS protocol according to the stroke severity and to find out the EEG parameters to predict the better recovery in subacute stroke patients with severe upper extremity hemiparesis. ETHICS AND DISSEMINATION: The study was approved by the Seoul National University Bundang Hospital Institutional Review Board (IRB No. B-1806-475-006) and will be carried out in accordance with the approved guidelines. The results of the trial will be submitted for publication in a peer-reviewed journal.

Comparisons between end-effector and exoskeleton rehabilitation robots regarding upper extremity function among chronic stroke patients with moderate-to-severe upper limb impairment.

End-effector (EE) and exoskeleton (Exo) robots have not been directly compared previously. The present study aimed to directly compare EE and Exo robots in chronic stroke patients with moderate-to-severe upper limb impairment. This single-blinded, randomised controlled trial included 38 patients with stroke who were admitted to the rehabilitation hospital. The patients were equally divided into EE and Exo groups. Baseline characteristics, including sex, age, stroke type, brain lesion side (left/right), stroke duration, Fugl-Meyer Assessment (FMA)-Upper Extremity score, and Wolf Motor Function Test (WMFT) score, were assessed. Additionally, impairment level (FMA, motor status score), activity (WMFT), and participation (stroke impact scale [SIS]) were evaluated. There were no significant differences in baseline characteristics between the groups. After the intervention, improvements were significantly better in the EE group with regard to activity and participation (WMFT-Functional ability rating scale, WMFT-Time, and SIS-Participation). There was no intervention-related adverse event. The EE robot intervention is better than the Exo robot intervention with regard to activity and participation among chronic stroke patients with moderate-to-severe upper limb impairment. Further research is needed to confirm this novel finding.

Robot-assisted gait training for balance and lower extremity function in patients with infratentorial stroke: a single-blinded randomized controlled trial.

BACKGROUND: Balance impairments are common in patients with infratentorial stroke. Although robot-assisted gait training (RAGT) exerts positive effects on balance among patients with stroke, it remains unclear whether such training is superior to conventional physical therapy (CPT). Therefore, we aimed to investigate the effects of RAGT combined with CPT and compared them with the effects of CPT only on balance and lower extremity function among survivors of infratentorial stroke. METHODS: This study was a single-blinded, randomized controlled trial with a crossover design conducted at a single rehabilitation hospital. Patients (n = 19; 16 men, three women; mean age: 47.4 ± 11.6 years) with infratentorial stroke were randomly allocated to either group A (4 weeks of RAGT+CPT, followed by 4 weeks of CPT+CPT) or group B (4 weeks of CPT+CPT followed by 4 weeks of RAGT+CPT). Changes in dynamic and static balance as indicated by Berg Balance Scale scores were regarded as the primary outcome measure. Outcome measures were evaluated for each participant at baseline and after each 4-week intervention period. RESULTS: No significant differences in outcome-related variables were observed between group A and B at baseline. In addition, no significant time-by-group interactions were observed for any variables, indicating that intervention order had no effect on lower extremity function or balance. Significantly greater improvements in secondary functional outcomes such as lower extremity Fugl-Meyer assessment (FMA-LE) and scale for the assessment and rating of ataxia (SARA) were observed following the RAGT+CPT intervention than following the CPT+CPT intervention. CONCLUSION: RAGT produces clinically significant improvements in balance and lower extremity function in individuals with infratentorial stroke. Thus, RAGT may be useful for patients with balance impairments secondary to other pathologies. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02680691. Registered 09 February 2016; retrospectively registered.

Virtual Reality Rehabilitation With Functional Electrical Stimulation Improves Upper Extremity Function in Patients With Chronic Stroke: A Pilot Randomized Controlled Study.

OBJECTIVE: To compare virtual reality (VR) combined with functional electrical stimulation (FES) with cyclic FES for improving upper extremity function and health-related quality of life in patients with chronic stroke. DESIGN: A pilot, randomized, single-blind, controlled trial. SETTING: Stroke rehabilitation inpatient unit. PARTICIPANTS: Participants (N=48) with hemiplegia secondary to a unilateral stroke for >3 months and with a hemiplegic wrist extensor Medical Research Council scale score ranging from 1 to 3. INTERVENTIONS: FES was applied to the wrist extensors and finger extensors. A VR-based wearable rehabilitation device was used combined with FES and virtual activity-based training for the intervention group. The control group received cyclic FES only. Both groups completed 20 sessions over a 4-week period. MAIN OUTCOME MEASURES: Primary outcome measures were changes in Fugl-Meyer Assessment-Upper Extremity and Wolf Motor Function Test scores. Secondary outcome measures were changes in Box and Block Test, Jebsen-Taylor Hand Function Test, and Stroke Impact Scale scores. Assessments were performed at baseline (t0) and at 2 weeks (t1), 4 weeks (t4), and 8 weeks (t8). Between-group comparisons were evaluated using a repeated-measures analysis of variance. RESULTS: Forty-one participants were included in the analysis. Compared with FES alone, VR-FES produced a substantial increase in Fugl-Meyer Assessment-distal score (P=.011) and marginal improvement in Jebsen-Taylor Hand Function Test-gross score (P=.057). VR-FES produced greater, although nonsignificant, improvements in all other outcome measures, except in the Stroke Impact Scale-activities of daily living/instrumental activities of daily living score. CONCLUSIONS: FES with VR-based rehabilitation may be more effective than cyclic FES in improving distal upper extremity gross motor performance poststroke.