Published papers

Background: Sensory disturbance is common following stroke and can exacerbate functional deficits, even in patients with relatively good motor function. In particular, loss of appropriate sensory feedback in severe sensory loss impairs manipulation capability. We hypothesized that task-oriented training with sensory feedback assistance would improve manipulation capability even without sensory pathway recovery. Methods. We developed a system that provides sensory feedback by transcutaneous electrical nerve stimulation (SENS) for patients with sensory loss, and investigated the feasibility of the system in a stroke patient with severe sensory impairment and mild motor deficit. The electrical current was modulated by the force exerted by the fingertips so as to allow the patient to identify the intensity. The patient had severe sensory loss due to a right thalamic hemorrhage suffered 27 months prior to participation in the study. The patient first practiced a cylindrical grasp task with SENS for 1 hour daily over 29 days. Pressure information from the affected thumb was fed back to the unaffected shoulder. The same patient practiced a tip pinch task with SENS for 1 hour daily over 4 days. Pressure information from the affected thumb and index finger was fed back to the unaffected and affected shoulders, respectively. We assessed the feasibility of SENS and examined the improvement of manipulation capability after training with SENS. Results: The fluctuation in fingertip force during the cylindrical grasp task gradually decreased as the training progressed. The patient was able to maintain a stable grip force after training, even without SENS. Pressure exerted by the tip pinch of the affected hand was unstable before intervention with SENS compared with that of the unaffected hand. However, they were similar to each other immediately after SENS was initiated, suggesting that the somatosensory information improved tip pinch performance. The patient's manipulation capability assessed by the Box and Block Test score improved through SENS intervention and was partly maintained after SENS was removed, until at least 7 months after the intervention. The sensory test score, however, showed no recovery after intervention. Conclusions: We conclude that the proposed system would be useful in the rehabilitation of patients with sensory loss. © 2013 Kita et al.; licensee BioMed Central Ltd.

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-sectionalsurvey 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. © 2013 The Authors.

Brain computer interfaces (BCIs) using event-related desynchronization (ERD) of the electroencephalogram (EEG), which is believed to represent increased activation of the sensorimotor cortex, have attracted attention as tools for rehabilitation of upper limb motor functions in hemiplegic stroke patients. However, it remains unclear whether the corticospinal excitability is actually correlated with ERD. The purpose of this study was to assess the association between the ERD magnitude and the excitability of primary motor cortex (M1) and spinal motoneurons. M1 excitability was tested by motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) using transcranial magnetic stimulation, and spinal motoneuronal excitability was tested by F-waves using peripheral nerve stimulation. Results showed that large ERD during motor imagery was associated with significantly increased F-wave persistence and reduced SICI, but no significant changes in ICF and the response average of F-wave amplitudes. Our findings suggest that ERD magnitude during motor imagery represents the instantaneous excitability of both M1 and spinal motoneurons. This study provides electrophysiological evidence that ERD-based BCI with motor imagery task increases corticospinal excitability as changes accompanying actual movements. © 2013 IEEE.

There is increasing interest in electroencephalogram (EEG)-based brain-computer interface (BCI) as a tool for rehabilitation of upper limb motor functions in hemiplegic stroke patients. This type of BCI often exploits mu and beta oscillations in EEG recorded over the sensorimotor areas, and their event-related desynchronization (ERD) following motor imagery is believed to represent increased sensorimotor cortex excitability. However, it remains unclear whether the sensorimotor cortex excitability is actually correlated with ERD. Thus we assessed the association of ERD with primary motor cortex (M1) excitability during motor imagery of right wrist movement. M1 excitability was tested by motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) with transcranial magnetic stimulation (TMS). Twenty healthy participants were recruited. The participants performed 7 s of rest followed by 5 s of motor imagery and received online visual feedback of the ERD magnitude of the contralateral hand M1 while performing the motor imagery task. TMS was applied to the right hand M1 when ERD exceeded predetermined thresholds during motor imagery. MEP amplitudes, SICI, and ICF were recorded from the agonist muscle of the imagined hand movement. Results showed that the large ERD during wrist motor imagery was associated with significantly increased MEP amplitudes and reduced SICI but no significant changes in ICF. Thus ERD magnitude during wrist motor imagery represents M1 excitability. This study provides electrophysiological evidence that a motor imagery task involving ERD may induce changes in corticospinal excitability similar to changes accompanying actual movements. © 2013 the American Physiological Society.

Objective: To determine whether visual evoked fields (VEFs) elicited by right and left hemifield stimulation differ in patients with unilateral spatial neglect that results from cerebrovascular accident. Methods: Pattern-reversal stimulation of the right and left hemifield was performed in three patients with left unilateral spatial neglect. Magnetoencephalography was recorded using a 160-channel system, and VEFs were quantified in the 400 ms after each stimulus. The presence or absence of VEF components at around 100 ms (P100m component) and 145 ms (N145m component) after stimulus onset was determined. The source of the VEF was determined using a single equivalent current dipole model for spherical volume conduction. All patients were evaluated using the behavioral inattention test (BIT). Results: In response to right hemifield stimulation, the P100m and N145m components of the VEF were evident in all three patients. In response to left hemifield stimulation, both components were evident in Patient 3, whereas only the P100m component was evident in Patient 1 and only the N145m component was evident in Patient 2. Patient 1 exhibited impairments on the line bisection and cancellation tasks of the BIT, Patient 2 exhibited impairments on the copying, drawing and cancellation tasks of the BIT, and Patient 3 exhibited impairments on the cancellation task of the BIT. Conclusions: These results demonstrate that early VEFs are disrupted in patients with unilateral spatial neglect and support the concept that deficits in visual processing differ according to the clinical subtype of unilateral spatial neglect and the lesion location. This study also demonstrates the feasibility of using magnetoencephalography to explore subtypes of neglect. © 2013 Mizuno, Tsuji, Rossetti, Pisella, Ohde and Liu.

Objective To evaluate the incidence of complications of intrathecal baclofen (ITB) therapy for spasticity in Japan, where a unique training course and nationwide registration are required. Materials and Methods An analysis of complications was performed in all patients who underwent ITB in Japan from 2005 to 2011. Prior to surgery, all the doctors involved took a one-day training course, which included hands-on training. Surgical techniques that avoided complications were emphasized. Results A total of 406 pumps were implanted in 400 patients (277 men, 123 women) having severe spasticity. Because this study is currently in progress, among the 400 patients, 78.3% (313/400) had finished a one-year observation follow-up. There were 369 adult and 31 juvenile (under 17 years old) patients, including 12 patients under nine years old. All-cause adverse events were seen in 148 patients (37%), and 93 (23.3%) of these were regarded as severe. Catheter problems were observed in 34 (8.5%) patients: catheter migration in 25 (6.3%), breakage in 6 (1.5%), obstruction in 2 (0.5%), kinking in 1 (0.3%), and dislodgement in 1 (0.3%). Pump trouble was observed in seven (1.8%) patients: alarm abnormality in one (0.3%), memory error in one (0.3%), delayed recovery in one (0.3%), rotation in one (0.3%), malfunction in one (0.3%), and abnormal infusion rate in two (0.6%). Device-related and surgical wound infection occurred in 12 patients (3%), and nine were regarded as severe. Leakage or subcutaneous accumulation of the cerebrospinal fluid was seen in 13 patients (3.3%). Conclusion The requirement of taking of a training course before starting ITB seemed to reduce complications. Although there were surgery-related complications, the rate of complications in Japan appeared to be lower than those reported in larger series of ITB. However, whether the reported rates can be primarily ascribed to a mandatory training course requires further investigations. © 2012 International Neuromodulation Society.

Objective: Pedaling is widely used for rehabilitation of locomotion because it induces muscle activity very similar to locomotion. Afferent stimulation is important for the modulation of spinal reflexes. Furthermore, supraspinal modulation plays an important role in spinal plasticity induced by electrical stimulation. We, therefore, expected that active pedaling combined with electrical stimulation could induce strong after-effects on spinal reflexes. Design: Twelve healthy adults participated in this study. They were instructed to perform 7. min of pedaling. We applied electrical stimulation to the common peroneal nerve during the extension phase of the pedaling cycle. We assessed reciprocal inhibition using a soleus H-reflex conditioning-test paradigm. The magnitude of reciprocal inhibition was measured before, immediately after, 15 and 30. min after active pedaling alone, electrical stimulation alone and active pedaling combined with electrical stimulation (pedaling. +. ES). Results: The amount of reciprocal inhibition was significantly increased after pedaling. +. ES. The after-effect of pedaling. +. ES on reciprocal inhibition was more prominent and longer lasting compared with pedaling or electrical stimulation alone. Conclusions: Pedaling. +. ES could induce stronger after-effects on spinal reciprocal inhibitory neurons compared with either intervention alone. Pedaling. +. ES might be used as a tool to improve locomotion and functional abnormalities in the patient with central nervous lesion. © 2012 Elsevier Ltd.

Objectives: Few studies have assessed short intracortical inhibition (SICI) in the affected hemisphere (AH) in a large number of patients with chronic stroke. In this study, SICI was assessed in chronic stroke patients with severe hemiparesis, and its relationship to clinical parameters was examined. Methods: The participants were 72 patients with chronic hemiparetic stroke. SICI of both the AH and the unaffected hemisphere (UH) was assessed. The relationships between SICI and the location of lesion, time from onset, and finger function were studied. Motor function of the paretic finger was assessed with the Stroke Impairment Assessment Set (SIAS) and the Fugl-Meyer test upper extremity motor score. To compare the results with those of healthy subjects, SICI was assessed in seven age-matched control subjects. Results: MEPs of the UH were evoked in all 72 subjects, and MEPs of the AH were evoked in 24 subjects. SICI of the AH was inversely correlated with paretic finger motor function and time from stroke onset. SICI of the UH was not correlated with either one. SICI of the UH was higher in the cortical lesion group than in the control group. Conclusions: The state of intracortical inhibitory neuron activity depends on the state of motor function and lesion site even in chronic stroke patients with severe hemiparesis. Significance: The inhibitory system of the AH is involved in functional recovery of the paretic hand even in the chronic stage of stroke. © 2012 International Federation of Clinical Neurophysiology.

Background: Maintaining or improving motor (balance) ability is essential to extending the healthy lifespan of elderly people, and developing effective and efficient strategies to prevent falls of elderly people is an urgent. The purpose of this study was to determine the effects of balance exercise on fall and fracture prevention for elderly people with poor balance. Methods: A 6-month, randomized controlled trial was conducted to verify whether one-leg standing with eyes open for a total of 1 min, three times a day (dynamic flamingo exercise) prevents falls and fractures. Setting and participants were elderly people ≥75 years of age and one-leg standing time ≤15.0 s living in their own home. They were visiting orthopaedic clinics for orthopaedic handicaps. Subjects with poor balance were allowed to hold on to something. If a subject's lifted leg touched the ground during the exercise, they were allowed to lift it again and continue so that they stood on one leg for a total of 60 s. Results: The dynamic flamingo exercise group (410 people; 86 men, 324 women) and the no exercise group (455 people; 78 men, 377 women) were compared. After dynamic flamingo exercise for 6 months, significant differences were seen in the increase in one-leg standing time with eyes open (men right/left, women right/left), in the improvement in independence in daily living (women), number of people who fell during the 6 months (women), and adverse events (women). The number of fractures was not significantly different for men or women. Conclusions: Dynamic flamingo exercise prevents falls but no significant difference was demonstrated in fracture prevention in elderly women with poor balance. © 2012 The Japanese Orthopaedic Association.

For the future manned exploration mission to the other planet, the change of motion characteristics due to the reduced gravity must be studied. Walking, especially, is the basic action of human life, and the efficient walking enables the exploration mission under the limited life-sustaining time and resources. To minimize the risk of injury and damaging of the life-supporting system, the safety of the walking must be studied. To simulate the micro-gravity on the earth, gravity compensation is required, and the wire suspension system is often used for gait analysis. In this system, a subject wears harness and will be suspended by the wire to apply an upward force to the center of mass of the subject. However, pulleys for many systems are fixed at a point and this will lead to inappropriate compensation. While the subject is underneath the pulley, the complete compensation can be achieved with suspension force parallel to the gravity. However, once the subject moved away from the initial position, the unloading force is no longer equal to the suspension force but fluctuate as the subject move. Considering this problem, this paper first represents the effect of force fluctuation to the gait property using the planar rimless wheel, one of the simplest models of locomotion. Gait under lunar gravity and under fixed point suspension is compared, and the effect of restoring force is analyzed. Then, a new gravity compensator with horizontal follower is proposed and its effectiveness is verified through rimless wheel experiment. © 2012 The Japan Society of Mechanical Engineers.

Because recovery of upper extremity (UE) function to a practical level has been difficult in many stroke patients, compensatory approaches have been emphasized. Based on researches indicating greater potential for brain plasticity, newer approaches targeting at functional restoration have been attempted. However, no intervention has been shown to be effective to improve hand function. We therefore devised a therapeutic approach to facilitate the use of the hemiparetic hand in daily life by combining EMG triggered electrical stimulation with a wrist splint, called hybrid assistive neuromuscular dynamic stimulation (HANDS). With HANDS, we demonstrated improved motor function, spasticity, functional scores and neurophysiological parameters in chronic stroke. With a RCT, we also demonstrated its effectiveness in subacute stroke. However, to be its candidates, electromyogram must be recorded from finger extensors, and it cannot be applied to patients with complete paralysis. For them, we recently developed a Brain Machine Interface (BMI) neurorehabilitation system. Based on analysis of volitionally decreased amplitudes of sensory motor rhythm during motor imagery involving extending the affected fingers, real-time visual feedback is provided. In patients with severe hemiparesis, we demonstrated its effectiveness with clinical scales, neuroimaging and electrophysiological studies. These newer interventions might offer useful neurorehabilitative tools for hemiparetic UE.