Ichiro Miyai

Japan Science and Technology Agency (JST), Edo, Tōkyō, Japan

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Publications (86)

  • Keiichi Kitajo · Yutaka Uno · Noriaki Hattori · [...] · Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: We demonstrate the first experimental evidence that fluctuations in electroencephalographic (EEG) resting-state connectivity are associated with recovery from stroke. We found that fluctuations in instantaneous brain states, quantified as the variance in EEG phase synchronized states, were correlated with motor-related subscores in the Functional Independence Measure, which estimates the recovery of activities of daily living (ADL) in stroke patients. The results suggest that the dynamic repertoire of spontaneous large-scale phase synchronization networks constrains functional networking and accounts for the ADL recovery.
    Chapter · Oct 2017
  • Masahito Mihara · Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: We provide a brief overview of the research and clinical applications of near-infrared spectroscopy (NIRS) in the neurorehabilitation field. NIRS has several potential advantages and shortcomings as a neuroimaging tool and is suitable for research application in the rehabilitation field. As one of the main applications of NIRS, we discuss its application as a monitoring tool, including investigating the neural mechanism of functional recovery after brain damage and investigating the neural mechanisms for controlling bipedal locomotion and postural balance in humans. In addition to being a monitoring tool, advances in signal processing techniques allow us to use NIRS as a therapeutic tool in this field. With a brief summary of recent studies investigating the clinical application of NIRS using motor imagery task, we discuss the possible clinical usage of NIRS in brain-computer interface and neurofeedback.
    Article · Jul 2016
  • [Show abstract] [Hide abstract] ABSTRACT: The frontal-subcortical circuits link the specific areas of the frontal cortex to the striatum, basal ganglia, and thalamus. Disruption of the frontal-subcortical circuits may lead to cognitive impairment with frontal lobe features. The putamen is a central component of frontal-subcortical circuits. Although putaminal lesions presumably lead to cognitive and behavioral changes, studies on frontal lobe dysfunctions after putaminal stroke are scarce. There are no previous studies that systematically examined frontal lobe functions with a focal putaminal lesion. The objective of this study is to demonstrate whether putaminal hemorrhage causes frontal lobe dysfunction. Cognitive functions, including various aspects of frontal lobe functions, were systematically assessed in 15 patients with left- or right-sided putaminal hemorrhage 2 months after the onset and compared with healthy controls. Patients did not have signs of aphasia, apraxia, or spatial neglect. They performed significantly worse on tests of frontal lobe function, including Letter-Number Sequencing (U = 22, P < .001), lexical fluency (U = 30, P < .001), and motor series subtest (U = 45, P = .004) of the Frontal Assessment Battery. On the Wisconsin Card Sorting Test, patients performed significantly worse for "categories achieved" (U = 29.5, P < .001), "perseverative errors" (U = 25, P < .001), and "set loss" (U = 49, P = .008). None showed behavioral impairment. Isolated putaminal hemorrhage causes modest frontal lobe dysfunction without behavioral symptoms. Our findings indicate that isolated putaminal hemorrhage disrupts the dorsolateral-striato-pallido-thalamic circuits and causes executive dysfunction. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
    Article · Jul 2015 · Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association
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    I Miyai · A D Blau · M J Reding · B T Volpe
    File available · Dataset · Jul 2015
  • Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: After brain damage, use-dependent plasticity of the spared neural network plays a crucial role in improving neural deficits and promoting motor learning and relearning using the impaired limbs. In degenerative cerebellar diseases, it is to be elucidated whether a similar mechanism works or not, since pathological processes are basically progressive. The fundamental question regarding the efficacy of neurorehabilitation in cerebellar degenerative diseases, is whether it is beneficial in terms of both the short- and long-term effect. To answer this question, two important issues need to be considered. The first is whether impaired motor learning due to cerebellar dysfunction is compensated for by repeated practice, since the cerebellum plays a crucial role in motor learning. The second issue is how long functional gains can be sustained provided that intensive rehabilitation results in significant gains. Recent studies have shown that intensive rehabilitation focusing on balance and mobility improves motor function for a period of up to 1 year in patients with degenerative cerebellar diseases. To obtain meaningful long-term gains, a combination of intermittent intensive short-term rehabilitation and home-based practice and support may be a practical way of managing patients. Future studies may elucidate a potential role of neuromodulation coupled with rehabilitative intervention to enhance the gains and to minimize functional decline.
    Chapter · Jan 2015
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    [Show abstract] [Hide abstract] ABSTRACT: Background. Walking-related disability is the most frequent reason for inpatient stroke rehabilitation. Task-related practice is a critical component for improving patient outcomes. Objective. To test the feasibility of providing quantitative feedback about daily walking performance and motivating greater skills practice via remote sensing. Methods. In this phase III randomized, single blind clinical trial, patients participated in conventional therapies while wearing wireless sensors (triaxial accelerometers) at both ankles. Activity-recognition algorithms calculated the speed, distance, and duration of walking bouts. Three times a week, therapists provided either feedback about performance on a 10-meter walk (speed only) or walking speed feedback plus a review of walking activity recorded by the sensors (augmented). Primary outcomes at discharge included total daily walking time, derived from the sensors, and a timed 15-meter walk. Results. Sixteen rehabilitation centers in 11 countries enrolled 135 participants over 15 months. Sensors recorded more than 1800 days of therapy, 37 000 individual walking bouts, and 2.5 million steps. No significant differences were found between the 2 feedback groups in daily walking time (15.1 ± 13.1 vs 16.6 ± 14.3 minutes, P = .54) or 15-meter walking speed (0.93 ± 0.47 vs 0.91 ± 0.53 m/s, P = .96). Remarkably, 30% of participants decreased their total daily walking time over their rehabilitation stay. Conclusions. In this first trial of remote monitoring of inpatient stroke rehabilitation, augmented feedback beyond speed alone did not increase the time spent practicing or improve walking outcomes. Remarkably modest time was spent walking. Wireless sensing, however, allowed clinicians to audit skills practice and provided ground truth regarding changes in clinically important, mobility-related activities.
    Full-text available · Article · Sep 2014 · Neurorehabilitation and neural repair
  • Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: It remains to be elucidated whether there is a use- or dose-dependent effect of rehabilitative intervention on impairment and disability of spinocerebellar degeneration since the disease progressively damages cerebellar structure that plays a crucial role in motor learning. Moreover there is a trade-off between functional improvement after rehabilitation and functional deterioration due to disease progression. Recent clinical trials from Germany and Japan have demonstrated that comprehensive intensive rehabilitation focusing on balance function have immediate and lasting effect up to 1 year on ataxia and gait disorder in patients with spinocerebellar degeneration. For sustained gain after the intensive rehabilitation, customized attempts to boost patients' daily activities according to their ability appears to be important.
    Article · Dec 2013
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    W Ilg · AJ Bastian · S Boesch · [...] · D Timmann
    [Show abstract] [Hide abstract] ABSTRACT: Treatment of motor symptoms of degenerative cerebellar ataxia remains difficult. Yet there are recent developments that are likely to lead to significant improvements in the future. Most desirable would be a causative treatment of the underlying cerebellar disease. This is currently available only for a very small subset of cerebellar ataxias with known metabolic dysfunction. However, increasing knowledge of the pathophysiology of hereditary ataxia should lead to an increasing number of medically sensible drug trials. In this paper, data from recent drug trials in patients with recessive and dominant cerebellar ataxias will be summarized. There is consensus that up to date, no medication has been proven effective. Aminopyridines and acetazolamide are the only exception, which are beneficial in patients with episodic ataxia type 2. Aminopyridines are also effective in a subset of patients presenting with downbeat nystagmus. As such, all authors agreed that the mainstays of treatment of degenerative cerebellar ataxia are currently physiotherapy, occupational therapy, and speech therapy. For many years, well-controlled rehabilitation studies in patients with cerebellar ataxia were lacking. Data of recently published studies show that coordinative training improves motor function in both adult and juvenile patients with cerebellar degeneration. Given the well-known contribution of the cerebellum to motor learning, possible mechanisms underlying improvement will be outlined. There is consensus that evidence-based guidelines for the physiotherapy of degenerative cerebellar ataxia need to be developed. Future developments in physiotherapeutical interventions will be discussed including application of non-invasive brain stimulation.
    Full-text available · Article · Nov 2013 · The Cerebellum
  • Ichiro Miyai · Noriaki Hattori · Masahito Mihara · [...] · Hajime Yagura
    Article · Aug 2013 · Clinical Neurophysiology
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    [Show abstract] [Hide abstract] ABSTRACT: Balance problems are a major sequelae of stroke and are implicated in poor recovery of activities of daily living. In a cross-sectional study, using 50-channel event-related functional near-infrared spectroscopy we previously reported a significant correlation between individual balance ability after stroke and postural perturbation-related cortical activation in the supplementary motor area (SMA) and the prefrontal cortex. However, the neural mechanisms underlying balance recovery after stroke remain unclear. Herein, we examined the cortical involvement in balance recovery after stroke by determining longitudinal regional cortical activation changes in patients with hemiplegic stroke. Twenty patients with subcortical stroke admitted to our hospital for post-acute inpatient rehabilitation participated in this study. Before and after intensive inpatient physical and occupational therapy rehabilitation, we evaluated cortical activation associated with external postural perturbations induced by combined brisk forward and backward movement of a platform. Postural perturbation-related cortical activation in the SMA of the affected and unaffected hemispheres was significantly increased after intensive rehabilitation. The increment of the postural-perturbation-related oxygenated hemoglobin signals in the SMA of the unaffected hemisphere was significantly correlated with the gain in balance function measured by the Berg Balance Scale. These findings support the conclusion that the SMA plays an important role in postural balance control, and suggest that the SMA is a crucial area for balance recovery after hemiplegic stroke.
    Full-text available · Article · May 2013 · NeuroImage
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    Masahito Mihara · Noriaki Hattori · Megumi Hatakenaka · [...] · Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: Background and purpose: Despite the findings that motor imagery and execution are supposed to share common neural networks, previous studies using imagery-based rehabilitation have revealed inconsistent results. In the present study, we investigated whether feedback of cortical activities (neurofeedback) using near-infrared spectroscopy could enhance the efficacy of imagery-based rehabilitation in stroke patients. Methods: Twenty hemiplegic patients with subcortical stroke received 6 sessions of mental practice with motor imagery of the distal upper limb in addition to standard rehabilitation. Subjects were randomly allocated to REAL and SHAM groups. In the REAL group, cortical hemoglobin signals detected by near-infrared spectroscopy were fed back during imagery. In the SHAM group, irrelevant randomized signals were fed back. Upper limb function was assessed using the finger and arm subscales of the Fugl-Meyer assessment and the Action Research Arm Test. Results: The hand/finger subscale of the Fugl-Meyer assessment showed greater functional gain in the REAL group, with a significant interaction between time and group (F(2,36)=15.5; P<0.001). A significant effect of neurofeedback was revealed even in severely impaired subjects. Imagery-related cortical activation in the premotor area was significantly greater in the REAL group than in the SHAM group (T(58)=2.4; P<0.05). Conclusions: Our results suggest that near-infrared spectroscopy-mediated neurofeedback may enhance the efficacy of mental practice with motor imagery and augment motor recovery in poststroke patients with severe hemiparesis.
    Full-text available · Article · Feb 2013 · Stroke
  • Masahito Mihara · Noriaki Hattori · Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: Near-infrared spectroscopy (NIRS) is a unique neuroimaging tool that allows for monitoring of cortical activation during daily activities such as standing, walking, and reaching. NIRS uses near-infrared light that penetrates skin and skull bone to measure task-related cortical vascular responses. Although NIRS cannot monitor deep brain structures such as the basal ganglia and cerebellum, its less onerous constraints are a characteristic advantage of this methodology. NIRS has been applied successfully in studies investigating the neural mechanisms for gait and postural control that are challenging to perform using other modalities. NIRS has also been utilized as a therapeutic tool in neurofeedback and brain-machine interface applications. Despite some shortcomings, NIRS could be a useful tool in the motor control study in a clinical setting, and might be effective as a therapeutic intervention.
    Article · Jan 2013 · Current Clinical Neurology
  • Ichiro Miyai · Masahito Mihara · Noriaki Hattori · [...] · Hajime Yagura
    [Show abstract] [Hide abstract] ABSTRACT: Recent studies of functional neuroimaging and clinical neurophysiology have implied that functional recovery after stroke is associated with use-dependent plasticity of the damaged brain. However the property of the reorganized neural network depends on site and size of the lesion, which makes it difficult to assess what the adaptive plasticity is. From clinical point of view there is accumulating randomized controlled trials for the benefit of task-oriented rehabilitative intervention including constraint-induced movement therapy, robotics, and body-weight supported treadmill training. However dose-matched control intervention is usually as effective as a specific intervention. This raises a question regarding the specificity of a task-oriented intervention. Second question is whether such intervention goes beyond the biological destiny of human. Specifically there is no known strategy enhancing recovery of severely impaired hand. To augment functional gain, several methods of neuro-modulation may bring break-through on the assumption that they induce greater adaptive plasticity. Such neuro-modulative methods include neuropharmacological modulation, brain stimulation using transcranial magnetic stimulation and direct current stimulation, peripheral nerve stimulation, neurofeedback using real-time fMRI and real-time fNIRS, and brain-machine interface. A preliminary randomized controlled trial regarding real-time feedback of premotor activities revealed promising results for recovery of paretic hand in patients with stroke.
    Article · Nov 2012
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    Masahito Mihara · Ichiro Miyai
    Full-text available · Chapter · Apr 2012
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    Masahito Mihara · Ichiro Miyai · Noriaki Hattori · [...] · Kisou Kubota
    [Show abstract] [Hide abstract] ABSTRACT: Despite its remarkable effect on the activities of daily living, the precise mechanism underlying balance control after stroke remains to be elucidated. In this study, we investigated the cortical activation induced by postural perturbation in 20 patients with stroke using a 50-channel event-related functional near-infrared spectroscopy. A combination of brisk forward and backward movements of a platform without any prior cue was used as an external postural perturbation. Multi-participant analysis of oxygenated hemoglobin signals showed postural perturbation-related cortical activation in the prefrontal cortical areas in both hemispheres as well as the premotor and parietal association cortical areas in the unaffected hemisphere. Regression analysis using the individual Berg Balance Scale as the regressor showed a significant positive correlation between balance ability and the postural perturbation-related changes in oxygenated hemoglobin signals in the supplementary motor areas and prefrontal cortical areas in both hemispheres. Consistent with the previous findings in healthy participants, these findings suggest that the broad cortical network, including the prefrontal, premotor, supplementary motor, and parietal cortical areas in both hemispheres, was essential for balance control even in poststroke patients.
    Full-text available · Article · Mar 2012 · Neuroreport
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    Masahito Mihara · Ichiro Miyai · Noriaki Hattori · [...] · Kisou Kubota
    [Show abstract] [Hide abstract] ABSTRACT: Accumulating evidence indicates that motor imagery and motor execution share common neural networks. Accordingly, mental practices in the form of motor imagery have been implemented in rehabilitation regimes of stroke patients with favorable results. Because direct monitoring of motor imagery is difficult, feedback of cortical activities related to motor imagery (neurofeedback) could help to enhance efficacy of mental practice with motor imagery. To determine the feasibility and efficacy of a real-time neurofeedback system mediated by near-infrared spectroscopy (NIRS), two separate experiments were performed. Experiment 1 was used in five subjects to evaluate whether real-time cortical oxygenated hemoglobin signal feedback during a motor execution task correlated with reference hemoglobin signals computed off-line. Results demonstrated that the NIRS-mediated neurofeedback system reliably detected oxygenated hemoglobin signal changes in real-time. In Experiment 2, 21 subjects performed motor imagery of finger movements with feedback from relevant cortical signals and irrelevant sham signals. Real neurofeedback induced significantly greater activation of the contralateral premotor cortex and greater self-assessment scores for kinesthetic motor imagery compared with sham feedback. These findings suggested the feasibility and potential effectiveness of a NIRS-mediated real-time neurofeedback system on performance of kinesthetic motor imagery. However, these results warrant further clinical trials to determine whether this system could enhance the effects of mental practice in stroke patients.
    Full-text available · Article · Mar 2012 · PLoS ONE
  • Ichiro Miyai · Mizuki Ito · Noriaki Hattori · [...] · Masatoyo Nishizawa
    [Show abstract] [Hide abstract] ABSTRACT: To investigate short- and long-term effects of intensive rehabilitation on ataxia, gait, and activities of daily living (ADLs) in patients with degenerative cerebellar disease. A total of 42 patients with pure cerebellar degeneration were randomly assigned to the immediate group or the delayed-entry control group. The immediate group received 2 hours of inpatient physical and occupational therapy, focusing on coordination, balance, and ADLs, on weekdays and 1 hour on weekends for 4 weeks. The control group received the same intervention after a 4-week delay. Short-term outcome was compared between the immediate and control groups. Long-term evaluation was done in both groups at 4, 12, and 24 weeks after the intervention. Outcome measures included the assessment and rating of ataxia, Functional Independence Measure, gait speed, cadence, functional ambulation category, and number of falls. The immediate group showed significantly greater functional gains in ataxia, gait speed, and ADLs than the control group. Improvement of truncal ataxia was more prominent than limb ataxia. The gains in ataxia and gait were sustained at 12 weeks and 24 weeks, respectively. At least 1 measure was better than at baseline at 24 weeks in 22 patients. Short-term benefit of intensive rehabilitation was evident in patients with degenerative cerebellar diseases. Although functional status tended to decline to the baseline level within 24 weeks, gains were maintained in more than half of the participants.
    Article · Dec 2011 · Neurorehabilitation and neural repair
  • Ichiro Miyai
    [Show abstract] [Hide abstract] ABSTRACT: Cerebellar Ataxia Rehabilitation trial tested if intensive rehabilitation improved ataxia, gait, and activities of daily living (ADLs) in 42 patients with degenerative cerebellar diseases. They were randomly assigned to the immediate intervention group or the delayed-entry control group. The immediate group received 1 h physical and 1 h occupational therapy for 4 weeks and delayed-entry control group received the same intervention after 4-week delay. The immediate group showed significantly greater functional gains in ataxia, gait speed, and ADLs than control. The improvements in ataxia and gait speed were sustained at 12 and 24 weeks after the intervention, respectively. Further strategies inducing meaningful gains for a longer period should be investigated.
    Article · Nov 2011 · The Cerebellum
  • Ichiro Miyai
    Article · Nov 2011
  • Ichiro Miyai
    Article · Nov 2011

Publication Stats

3k Citations


  • 2010
    • Japan Science and Technology Agency (JST)
      Edo, Tōkyō, Japan
  • 2001
    • Osaka City University
      Ōsaka, Ōsaka, Japan
    • Toneyama National Hospital - Toyonaka
      Toyonaka, Ōsaka, Japan
  • 1997
    • White Plains Hospital
      White Plains, New York, United States