Michiyuki Kawakami

Brain-computer interface training combined with transcranial direct current stimulation in patients with chronic severe hemiparesis: Proof of concept study.

OBJECTIVE Brain-computer interface technology has been applied to stroke patients to improve their motor function. Event-related desynchronization during motor imagery, which is used as a brain-computer interface trigger, is sometimes difficult to detect in stroke patients. Anodal transcranial direct current stimulation (tDCS) is known to increase event-related desynchronization. This study investigated the adjunctive effect of anodal tDCS for brain-computer interface training in patients with severe hemiparesis. SUBJECTS Eighteen patients with chronic stroke. DESIGN A non-randomized controlled study. METHODS Subjects were divided between a brain-computer interface group and a tDCS- brain-computer interface group and participated in a 10-day brain-computer interface training. Event-related desynchronization was detected in the affected hemisphere during motor imagery of the affected fingers. The tDCS-brain-computer interface group received anodal tDCS before brain-computer interface training. Event-related desynchronization was evaluated before and after the intervention. The Fugl-Meyer Assessment upper extremity motor score (FM-U) was assessed before, immediately after, and 3 months after, the intervention. RESULTS Event-related desynchronization was significantly increased in the tDCS- brain-computer interface group. The FM-U was significantly increased in both groups. The FM-U improvement was maintained at 3 months in the tDCS-brain-computer interface group. CONCLUSION Anodal tDCS can be a conditioning tool for brain-computer interface training in patients with severe hemiparetic stroke.

Clinical usefulness and validity of robotic measures of reaching movement in hemiparetic stroke patients

BackgroundVarious robotic technologies have been developed recently for objective and quantitative assessment of movement. Among them, robotic measures derived from a reaching task in the KINARM Exoskeleton device are characterized by their potential to reveal underlying motor control in reaching movements. The aim of this study was to examine the clinical usefulness and validity of these robot-derived measures in hemiparetic stroke patients.MethodsFifty-six participants with a hemiparetic arm due to chronic stroke were enrolled. The robotic assessment was performed using the Visually Guided Reaching (VGR) task in the KINARM Exoskeleton, which allows free arm movements in the horizontal plane. Twelve parameters were derived based on motor control theory. The following clinical assessments were also administered: the proximal upper limb section in the Fugl-Meyer Assessment (FMA-UE(A)), the proximal upper limb part in the Stroke Impairment Assessment Set (SIAS-KM), the Modified Ashworth Scale for the affected elbow flexor muscles (MAS elbow), and seven proximal upper limb tasks in the Wolf Motor Function Test (WMFT). To explore which robotic measures represent deficits of motor control in the affected arm, the VGR parameters in the paretic arm were compared with those in the non-paretic arm using the Wilcoxon signed rank test. Then, to explore which VGR parameters were related to overall motor control regardless of the paresis, correlations between the paretic and non-paretic arms were examined. Finally, to investigate the relationships between the robotic measures and the clinical scales, correlations between the VGR parameters and clinical scales were investigated. Spearman’s rank correlation coefficients were used for all correlational analyses.ResultsEleven VGR parameters on the paretic side were significantly different from those on the non-paretic side with large effect sizes (|effect size| = 0.76–0.87). Ten VGR parameters correlated significantly with FMA-UE(A) (|r| = 0.32–0.60). Eight VGR parameters also showed significant correlations with SIAS-KM (|r| = 0.42–0.49), MAS elbow (|r| = 0.44–0.48), and the Functional Ability Scale of the WMFT (|r| = 0.52–0.64).ConclusionsThe robot-derived measures could successfully differentiate between the paretic arm and the non-paretic arm and were valid in comparison to the well-established clinical scales.

Effects of Quadripulse Stimulation on Human Motor Cortex Excitability: A Replication Study

Affiliations. a Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK b Neurology Unit, University-Hospital S. Maria della Misericordia, Udine, Italy c Department of Health and Sports, Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata City, Japan d Department of Rehabilitation Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan † These authors contributed equally to this work.

Modulation of cortical and spinal inhibition with functional recovery of upper extremity motor function among patients with chronic stroke

PURPOSE We hypothesized that recovery of upper extremity motor function is associated with reduction of intracortical inhibition and improved reciprocal inhibition. This study examines the relationships of functional recovery in chronic stroke with the intracortical inhibition and spinal reciprocal inhibition. METHODS Participants were 61 patients with chronic hemiparetic stroke. The participants were applied hybrid assistive neuromuscular dynamic stimulation (HANDS) therapy for 3 weeks. The Fugl-Meyer test upper extremity motor score (FM) and modified Ashworth scale (MAS) were assessed before (T0), immediately after (T1) and 3 months after (T2) the end of HANDS therapy. A paired pulse TMS paradigm was applied to assess short intracortical inhibition (SICI). Reciprocal inhibition (RI) was assessed with H reflex conditioning-test paradigm. RESULTS FM and MAS were improved until T2. The change of FM from T0 to T2 was positively correlated with the change in affected SICI from T0 toT1. The change of wrist MAS from T0 to T1 was positively correlated with the change of RI. CONCLUSIONS In chronic stroke patients with moderate or severe hemiparesis, well-recovered patients showed disinhibition of ipsilesional hemisphere and increased resiprocal inhibition of forearm.

Relationship between spasticity and spinal neural circuits in patients with chronic hemiparetic stroke

Spasticity is a common problem in patients with stroke that contributes to motor dysfunction. However, the pathophysiological mechanisms underlying spasticity are not fully understood. The purpose of the present study was to explain the relationship between features of spinal neural circuits assessed using electrophysiological techniques and the clinical manifestations of stroke. The participants were 71 patients with chronic hemiparetic stroke. To assess spinal neural circuits, Hmax/Mmax of the forearm flexor muscles and reciprocal inhibition (RI) between forearm extensor and flexor muscles with the H reflex conditioning-test paradigm were measured. The relationships between electrophysiological parameters and clinical variables (age, time from stroke onset, upper extremity functional scores, and spasticity) were then analyzed. It was found that the third phase of RI (RI-3) correlated with the modified Ashworth scores of the wrist and finger flexors. No other correlations were found between electrophysiological and clinical measures. These results suggest that RI-3 is associated with spasticity and may be helpful to understand the basis of post-stroke spasticity.

The effects of patterned electrical stimulation combined with voluntary contraction on spinal reciprocal inhibition in healthy individuals

The aim of this study was to examine the effects of voluntary contraction (VC) on the modulation of reciprocal inhibition induced by patterned electrical stimulation (PES) in healthy individuals. Twelve healthy volunteers participated in this study. PES was applied to the common peroneal nerve with a train of 10 pulses at 100 Hz every 2 s for 20 min. VC comprised repetitive ankle dorsiflexion at a frequency of 0.5 Hz for 20 min. All participants performed the following three tasks: (i) VC alone, (ii) PES alone, and (iii) PES combined with VC (PES+VC). Reciprocal inhibition was assessed using a soleus H-reflex conditioning-test paradigm at the time points of before, immediately after, 10 min after, 20 min after, and 30 min after the tasks. PES+VC increased the amount of reciprocal inhibition, with after-effects lasting up to 20 min. PES alone increased reciprocal inhibition and maintained the after-effects on reciprocal inhibition for 10 min, whereas VC alone increased only immediately after the task. VC could modulate the plastic changes in spinal reciprocal inhibition induced by PES in healthy individuals. PES combined with VC has a potential to modulate impaired reciprocal inhibition and it may facilitate functional recovery and improve locomotion after central nervous system lesions.

Effect of Core Stability Training on Trunk Function, Standing Balance, and Mobility in Stroke Patients: A Randomized Controlled Trial.

Background. Trunk function is important for standing balance, mobility, and functional outcome after stroke, but few studies have evaluated the effects of exercises aimed at improving core stability in stroke patients. Objective. To investigate the effectiveness of core stability training on trunk function, standing balance, and mobility in stroke patients. Methods. An assessor-blinded, randomized controlled trial was undertaken in a stroke rehabilitation ward, with 32 participants randomly assigned to an experimental group or a control group (n = 16 each). The experimental group received 400 minutes of core stability training in place of conventional programs within total training time, while the control group received only conventional programs. Primary outcome measures were evaluated using the Trunk Impairment Scale (TIS), which reflects trunk function. Secondary outcome measures were evaluated by pelvic tilt active range of motion in the sagittal plane, the Balance Evaluation Systems Test–brief version (Brief-BESTest), Functional Reach test, Timed Up-and-Go test (TUG), and Functional Ambulation Categories (FAC). A general linear repeated-measures model was used to analyze the results. Results. A treatment effect was found for the experimental group on the dynamic balance subscale and total score of the TIS (P = .002 and P < .001, respectively), pelvic tilt active range of motion (P < .001), Brief-BESTest (P < .001), TUG (P = .008), and FAC (P = .022). Conclusions. Core stability training has beneficial effects on trunk function, standing balance, and mobility in stroke patients. Our findings might provide support for introducing core stability training in stroke rehabilitation.

Hybrid Assistive Neuromuscular Dynamic Stimulation Therapy: A New Strategy for Improving Upper Extremity Function in Patients with Hemiparesis following Stroke

Hybrid Assistive Neuromuscular Dynamic Stimulation (HANDS) therapy is one of the neurorehabilitation therapeutic approaches that facilitates the use of the paretic upper extremity (UE) in daily life by combining closed-loop electromyography- (EMG-) controlled neuromuscular electrical stimulation (NMES) with a wrist-hand splint. This closed-loop EMG-controlled NMES can change its stimulation intensity in direct proportion to the changes in voluntary generated EMG amplitudes recorded with surface electrodes placed on the target muscle. The stimulation was applied to the paretic finger extensors. Patients wore a wrist-hand splint and carried a portable stimulator in an arm holder for 8 hours during the daytime. The system was active for 8 hours, and patients were instructed to use their paretic hand as much as possible. HANDS therapy was conducted for 3 weeks. The patients were also instructed to practice bimanual activities in their daily lives. Paretic upper extremity motor function improved after 3 weeks of HANDS therapy. Functional improvement of upper extremity motor function and spasticity with HANDS therapy is based on the disinhibition of the affected hemisphere and modulation of reciprocal inhibition. HANDS therapy may offer a promising option for the management of the paretic UE in patients with stroke.

Asymmetrical skull deformity in children with cerebral palsy: Frequency and correlation with postural abnormalities and deformities

OBJECTIVE Asymmetrical skull deformity is frequently seen in children with cerebral palsy, and may contribute to postural abnormalities and deformities. The aim of this cross-sectional- survey was to determine the frequency of asymmetrical skull deformity and its correlation with clinical parameters. METHODS A 10-item checklist for asymmetrical skull deformity, postural abnormalities, and deformities was developed, and its inter-rater reliability was tested. A total of 110 participants aged 1-18 years (mean age 9.3 years (standard deviation 4.7)) was assessed using the checklist. The frequency of asymmetrical skull deformity was analysed and related to the Gross Motor Function Classification System (GMFCS), postural abnormalities, and deformities. RESULTS The reliability of the checklist was satisfactory (κ > 0.8). Asymmetrical skull deformity was observed in 44 children, 24 showing right and 20 showing left flat occipital deformity. Its frequency was significantly related to GMFCS and with the patterns of asymmetrical posture and deformities (p < 0.05). Children with right flat occipital asymmetrical skull deformity showed predominantly rightward facial direction and right-side-dominant asymmetrical tonic neck reflex, left convex scoliosis, right-side-elevated pelvic obliquity, and left-sided hip dislocation. Those with left flat occipital asymmetrical skull deformity demonstrated the reverse tendency. CONCLUSION Asymmetrical skull deformity is frequent in cerebral palsy and closely related to asymmetrical posture and deformities. This information will be useful to manage these problems.

Nitrogen balance in patients with hemiparetic stroke during the subacute rehabilitation phase.

BACKGROUND In highly invasive diseases, metabolism commonly changes. Hypercatabolism is frequent in acute stroke, and nitrogen balance tends to be negative. However, there has been no study describing nitrogen balance in subacute and chronic stroke patients. The present study aimed to examine nitrogen balance in the subacute and chronic phases and to identify the factors related to it. METHODS Nitrogen balance was calculated from the collected urine of 56 patients with subacute stroke [mean (SD) 53.8 (18.4) days post-stroke] who were admitted for rehabilitation for their first-ever ischaemic or nonsurgical haemorrhagic stroke. In the first experiment, their nitrogen balance was measured during the rehabilitation phase, and factors (type, severity of hemiparesis, activities of daily living, dysphagia and malnutrition status) related to it were evaluated. The second experiment was performed to describe the time course of nitrogen balance in 31 consecutive patients, with assessments made at admission and at discharge. RESULTS Nitrogen balance was positive in all patients in the subacute phase. A significant difference was seen in nitrogen balance between high and low fat-free mass in male patients. In the chronic phase, nitrogen balance was positive in 96% of the patients. There was no significant difference in nitrogen balance between discharge and admission. CONCLUSIONS In the subacute and chronic phases of stroke, it was confirmed that hypercatabolism had resolved and that intensive rehabilitation is possible in the convalescent period of stroke.