Publications by authors named "Ryosuke Kitatani"

12 Publications

  • Page 1 of 1

Immediate effects of stance and swing phase training on gait in patients with stroke.

Int J Rehabil Res 2021 06;44(2):152-158

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto.

To compare the effects of gait trainings targeting the stance (stance training) and the swing phases (swing training) among the subjects with stroke, and quantify the characteristics in the subjects who benefitted from either the stance training or the swing training. Sixteen subjects with stroke performed the stance training, which focused on the center of pressure to move from the heel to the forefoot, and the swing training, which focused on the improvement of hip flexion in the swing phase. To investigate the immediate effects of the stance training and the swing training, the instrumented gait analysis was performed before and after training. To quantify the characteristics, subjects were divided into two groups based on the gait speed change. These two groups were compared using clinical examinations. After the stance training, the center of pressure displacement of the paretic limb was increased compared with the swing training. Subjects who benefitted from the stance training had slower Timed Up and Go and weaker paretic hip muscle strength than those who benefitted from the swing training. Stance training may be more effective in subjects with slower Timed Up and Go outcomes and weaker hip muscles.
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http://dx.doi.org/10.1097/MRR.0000000000000464DOI Listing
June 2021

Gait-combined transcranial alternating current stimulation modulates cortical control of muscle activities during gait.

Eur J Neurosci 2020 12 9;52(12):4791-4802. Epub 2020 Aug 9.

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Non-invasive brain stimulation has been of interest as a therapeutic tool to modulate cortical excitability. However, there is little evidence that oscillatory brain stimulation can modulate the cortical control of muscle activities during gait, which can be assessed using coherence analysis of paired surface electromyographic (EMG) recordings. This study aimed to investigate the effects of gait-combined transcranial alternating current stimulation (tACS) at the gait cycle frequency on the cortical control of muscle activities during gait using EMG-EMG coherence analysis. Fourteen healthy young adults participated in this study. All participants underwent 2 test conditions (real tACS and sham stimulation over the leg area of the primary motor cortex during 10-min treadmill walking). The average peak-to-peak amplitudes of the motor evoked potentials (MEPs) from the tibialis anterior (TA) and lateral gastrocnemius muscles in the sitting position and EMG-EMG coherences in the TA muscle, triceps surae muscles, quadriceps muscles, and hamstring muscles during gait were measured before and after stimulation. Entrainment effect was significantly higher during real tACS than during sham stimulation. After real tACS, the MEP amplitude and beta band (13-33 Hz) coherence area increased in the TA muscle. The change in MEP amplitude from the TA muscle was positively correlated with the change in beta band coherence area in the TA muscle. Gait-combined tACS can modulate the strength of descending neural drive to TA motoneurons during gait. This suggests that oscillatory brain stimulation is a useful therapeutic tool to modulate the cortical control of muscle activities during gait.
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http://dx.doi.org/10.1111/ejn.14919DOI Listing
December 2020

Gait kinematics and physical function that most affect intralimb coordination in patients with stroke.

NeuroRehabilitation 2019 Dec;45(4):493-499

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto, Japan.

Background: Disturbed lower limb coordination is thought to limit gait ability in patients with stroke. However, the relationship of lower limb coordination with gait kinematics and physical function has not yet been clarified.

Objective: The purpose of the study was to clarify the gait kinematic and physical function variables that most affect intralimb coordination by using the continuous relative phase (CRP) between the thigh and shank.

Methods: Fifteen participants with stroke were enrolled in this study. Kinematic and kinetic measurements were recorded during gait at preferred speeds. CRP was defined as the difference between the thigh and shank phase angles.

Results: Stepwise analysis revealed that non-paretic CRP during the propulsive phase was a determinant of gait speed. The paretic knee extension and flexion angles were determinants of the CRP during the propulsive phase in the non-paretic limb. Stepwise analysis showed that the paretic knee extension angle was a determinant of the CRP during the propulsive phase in the paretic limb. Stepwise analysis revealed that the paretic knee extensor muscle strength was a determinant of the CRP during the propulsive phase in both limbs.

Conclusions: Our study indicates that improvement in knee movement during the stance phase may improve coordination.
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http://dx.doi.org/10.3233/NRE-192923DOI Listing
December 2019

Gait-synchronized oscillatory brain stimulation modulates common neural drives to ankle muscles in patients after stroke: A pilot study.

Neurosci Res 2020 Jul 11;156:256-264. Epub 2019 Nov 11.

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

The present study aimed to investigate the long-term effects of gait intervention with transcranial alternating current stimulation (tACS) synchronized with gait cycle frequency on the cortical control of muscle activity during gait, using coherence analyses, in patients after stroke. Eight chronic post-stroke patients participated in a single-blinded crossover study, and 7 patients completed the long-term intervention. Each patient received tACS over the primary motor cortex foot area on the affected side, which was synchronized with individual gait cycle frequency, and sham stimulation during treadmill gait in a random order. Electrical neuromuscular stimulation was used to assist the paretic ankle movement in both conditions. After gait intervention with tACS, beta band (15-35 Hz) coherence, which is considered to have a cortical origin, significantly increased in the paretic tibialis anterior (TA) muscle during 6-min of over-ground gait. The change in beta band coherence in the paretic TA muscle was positively correlated with the change in gait distance. These results indicate that gait intervention with tACS synchronized with gait cycle frequency may induce gait-specific plasticity that modulates the common neural drive to the TA motoneurons on the paretic side during gait and leads to changes in gait function in patients after stroke.
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http://dx.doi.org/10.1016/j.neures.2019.11.001DOI Listing
July 2020

Gait-Synchronized Rhythmic Brain Stimulation Improves Poststroke Gait Disturbance: A Pilot Study.

Stroke 2019 11 10;50(11):3205-3212. Epub 2019 Sep 10.

The Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, Japan (T.M.).

Background and Purpose- Gait disturbance is one of serious impairments lowering activity of daily life in poststroke patients. The patients often show reduced hip and knee joint flexion and ankle dorsiflexion of the lower limbs during the swing phase of gait, which is partly controlled by the primary motor cortex (M1). In the present study, we investigated whether gait-synchronized rhythmic brain stimulation targeting swing phase-related M1 activity can improve gait function in poststroke patients. Methods- Eleven poststroke patients in the chronic phase participated in this single-blind crossover study. Each patient received oscillatory transcranial direct current stimulation over the affected M1 foot area and sham stimulation during treadmill gait. The brain stimulation was synchronized with individual gait rhythm, and the electrical current peaks reached immediately before initiation of the swing phase of the paretic lower limb. Ankle dorsiflexion was assisted by electrical neuromuscular stimulation in both real and sham conditions. Results- Regarding the effects of a single intervention, the speed of self-paced gait was significantly increased after oscillatory transcranial direct current stimulation, but not after sham stimulation (paired test, =0.009). After we administered the intervention repeatedly, self- and maximally paced gait speed and timed up and go test performance were significantly improved (self-paced: =8.91, =0.007, maximally paced: =7.09, =0.015 and timed up and go test: =12.27, =0.002), along with improved balance function and increased joint flexion of the paretic limbs during gait. Conclusions- These findings suggest that rhythmic brain stimulation synchronized with gait rhythm might be a promising approach to induce gait recovery in poststroke patients. Clinical Trial Registration- URL: https://www.umin.ac.jp/ctr/. Unique identifier: UMIN000013676.
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http://dx.doi.org/10.1161/STROKEAHA.119.025354DOI Listing
November 2019

Number of Synergies Is Dependent on Spasticity and Gait Kinetics in Children With Cerebral Palsy.

Pediatr Phys Ther 2018 01;30(1):34-38

Department of Physical Therapy (Mr Hashiguchi), Faculty of Health Science, Gunma Paz University, Gunma, Japan; Department of Physical Therapy (Drs Ohata and Yamada), Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Kuretake Special Support School and Kita Special Support School (Ms Osako), Kyoto, Japan; Kansai Rehabilitation Hospital (Dr Kitatani), Osaka, Japan; Aijinkai Rehabilitation Hospital (Ms Aga), Osaka, Japan; Department of Physical Therapy (Dr Masaki), Niigata University of Health and Welfare, Niigata, Japan.

Purpose: Children with cerebral palsy have motor dysfunctions, which are mainly associated with the loss of motor coordination. For the assessment of motor coordination, muscle synergies calculated by nonnegative matrix factorization have been investigated. However, the characteristics of muscle synergies in children with cerebral palsy are not understood.

Methods: This study compared the number of muscle synergies during gait between children with cerebral palsy and children with typical development and clarified whether certain clinical parameters differed according to the number of synergies.

Results: Children with cerebral palsy had significantly fewer synergies than children developing typically. The extent of spasticity and gait kinetics differed according to the number of synergies.

Conclusion: Increases in the number of synergies are limited by severe spasticity. The muscle synergies calculated by nonnegative matrix factorization have the potential to enable the quantification of motor coordination during gait.
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http://dx.doi.org/10.1097/PEP.0000000000000460DOI Listing
January 2018

Merging and Fractionation of Muscle Synergy Indicate the Recovery Process in Patients with Hemiplegia: The First Study of Patients after Subacute Stroke.

Neural Plast 2016 19;2016:5282957. Epub 2016 Dec 19.

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Loss of motor coordination is one of the main problems for patients after stroke. Muscle synergy is widely accepted as an indicator of motor coordination. Recently, the characteristics of muscle synergy were quantitatively evaluated using nonnegative matrix factorization (NNMF) with surface electromyography. Previous studies have identified that the number and structure of synergies were associated with motor function in patients after stroke. However, most of these studies had a cross-sectional design, and the changes in muscle synergy during recovery process are not clear. In present study, two consecutive measurements were conducted for subacute patients after stroke and the change of number and structure of muscle synergies during gait were determined using NNMF. Results showed that functional change did not rely on number of synergies in patients after subacute stroke. However, the extent of merging of the synergies was negatively associated with an increase in muscle strength and the range of angle at ankle joint. Our results suggest that the neural changes represented by NNMF were related to the longitudinal change of function and gait pattern and that the merging of synergy is an important marker in patients after subacute stroke.
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http://dx.doi.org/10.1155/2016/5282957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5206781PMC
August 2017

Ankle muscle coactivation and its relationship with ankle joint kinematics and kinetics during gait in hemiplegic patients after stroke.

Somatosens Mot Res 2016 06 18;33(2):79-85. Epub 2016 May 18.

a Department of Physical Therapy , Kyoto University , Kyoto , Japan ;

Introduction: Increased ankle muscle coactivation during gait is a compensation strategy for enhancing postural stability in patients after stroke. However, no previous studies have demonstrated that increased ankle muscle coactivation influenced ankle joint movements during gait in patients after stroke.

Purpose: To investigate the relationship between ankle muscle coactivation and ankle joint movements in hemiplegic patients after stroke.

Methods: Seventeen patients after stroke participated. The coactivation index (CoI) at the ankle joint was calculated separately for the first and second double support (DS1 and DS2, respectively) and single support (SS) phases on the paretic and non-paretic sides during gait using surface electromyography. Simultaneously, three-dimensional motion analysis was performed to measure the peak values of the ankle joint angle, moment, and power in the sagittal plane. Ground reaction forces (GRFs) of the anterior and posterior components and centers of pressure (COPs) trajectory ranges and velocities were also measured.

Results: The CoI during the SS phase on the paretic side was negatively related to ankle dorsiflexion angle, ankle plantarflexion moment, ankle joint power generation, and COP velocity on the paretic side. Furthermore, the CoI during the DS2 phase on both sides was negatively related to anterior GRF amplitude on each side.

Conclusion: Increased ankle muscle coactivation is related to decreased ankle joint movement during the SS phase on the paretic side to enhance joint stiffness and compensate for stance limb instability, which may be useful for patients who have paretic instability during the stance phase after stroke.
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http://dx.doi.org/10.1080/08990220.2016.1178636DOI Listing
June 2016

Clinical factors associated with ankle muscle coactivation during gait in adults after stroke.

NeuroRehabilitation 2016 Apr;38(4):351-7

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Background: Increased ankle muscle coactivation during gait represents an adaptation strategy to compensate for postural instability in adults after stroke. Although increased ankle muscle coactivation is correlated with gait disorders in adults after stroke, it remains unclear which physical impairments are the most predictive clinical factors explaining ankle muscle coactivation during gait.

Objective: To investigate these physical impairments in adults after stroke using stepwise multiple regression analyses.

Methods: The magnitude of ankle muscle coactivation during gait was quantified with a coactivation index (CoI) for the first and second double support (DS2), and single support (SS) phases in 44 community-dwelling adults after stroke. Paretic motor function, sensory function, spasticity, ankle muscle strength, and balance ability were evaluated.

Results: The regression analysis revealed that the balance ability and paretic ankle plantarflexor muscle strength were significant factors determining the CoI during the SS phase on the paretic side. For the CoI during the DS2 phase on the paretic side, only the balance ability was selected as a significant factor.

Conclusion: Adults with impaired balance ability and paretic ankle muscle weakness after stroke used a compensation strategy of increased ankle muscle coactivation on the paretic side to enhance postural stability during gait.
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http://dx.doi.org/10.3233/NRE-161326DOI Listing
April 2016

Ankle muscle coactivation during gait is decreased immediately after anterior weight shift practice in adults after stroke.

Gait Posture 2016 Mar 12;45:35-40. Epub 2016 Jan 12.

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Increased ankle muscle coactivation during gait has frequently been observed as an adaptation strategy to compensate for postural instability in adults after stroke. However, it remains unclear whether the muscle coactivation pattern increases or decreases after balance training. The aim of this study was to investigate the immediate effects of balance practice on ankle muscle coactivation during gait in adults after stroke. Standing balance practice performed to shift as much weight anteriorly as possible in 24 participants after stroke. The forward movement distance of the center of pressure (COP) during anterior weight shifting, gait speed, and ankle muscle activities during 10-m walking tests were measured immediately before and after balance practice. Forward movement of the COP during anterior weight shifting and gait speed significantly increased after balance practice. On the paretic side, tibialis anterior muscle activity significantly decreased during the single support and second double support phases, and the coactivation index at the ankle joint during the first double support and single support phases significantly decreased after balance practice. However, there were no significant relationships between the changes in gait speed, forward movement of the COP during anterior weight shifting, and ankle muscle coactivation during the stance phase. These results suggested that ankle muscle coactivation on the paretic side during the stance phase was decreased immediately after short-term anterior weight shift practice, which was not associated with improved gait speed or forward movement of the COP during anterior weight shifting in adults after stroke.
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http://dx.doi.org/10.1016/j.gaitpost.2016.01.006DOI Listing
March 2016

Descending neural drives to ankle muscles during gait and their relationships with clinical functions in patients after stroke.

Clin Neurophysiol 2016 Feb 3;127(2):1512-1520. Epub 2015 Nov 3.

Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

Objective: The objective of this study was to investigate the descending neural drive to ankle muscles during gait in stroke patients using a coherence analysis of surface electromyographic (EMG) recordings and the relationships of the drive with clinical functions.

Methods: EMG recordings of the paired tibialis anterior (TA), medial and lateral gastrocnemius (MG and LG), and TA-LG muscles were used to calculate intramuscular, synergistic, and agonist-antagonist muscle coherence, respectively, in 11 stroke patients and 9 healthy controls. Paretic motor function, sensory function, spasticity, ankle muscle strength, and gait performance were evaluated.

Results: Paretic TA-TA and MG-LG beta band (15-30 Hz) coherences were significantly lower compared with the non-paretic side and controls. TA-LG beta band coherence was significantly higher on both sides compared with controls. Paretic TA-TA beta band coherence positively correlated with gait speed, and paretic TA-LG beta band coherence negatively correlated with paretic ankle plantar flexor muscle strength.

Conclusions: The intramuscular and synergistic muscle neural drives were reduced during gait on the paretic side in stroke patients. The agonist-antagonist muscle neural drive was increased to compensate for paretic ankle muscle weakness.

Significance: Descending neural drive reorganization to agonist-antagonist muscles is important for patients with paretic ankle muscle weakness.
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http://dx.doi.org/10.1016/j.clinph.2015.10.043DOI Listing
February 2016

Reduction in energy expenditure during walking using an automated stride assistance device in healthy young adults.

Arch Phys Med Rehabil 2014 Nov 24;95(11):2128-33. Epub 2014 Jul 24.

Fujita Health University Hospital, Toyoake, Japan.

Objective: To investigate the effects of an automated stride assistance device that assists hip joint flexion and extension movement in energy expenditure during walking in healthy young adults using an expired gas method.

Design: Prospective, single-group design to compare the differences of energy expenditure between 2 assistive conditions.

Setting: Laboratory.

Participants: Healthy volunteers (N=10) aged 21 to 32 years.

Interventions: Not applicable.

Main Outcome Measures: Oxygen consumption per unit time (V˙o2) cost (ml·kg(-1)·m(-1)), and heart rate (beats/min) were measured in 2 assistive conditions (with 3-Nm hip motion assistance and without assistance) and at 2 walking speeds (comfortable walking speed [CWS] and maximum walking speed [MWS]).

Results: There were no significant differences in walking speed between the with- and without-assistance conditions at either the CWS or MWS. The V˙o2 cost and heart rate were significantly reduced in the with-assistance condition compared with the without-assistance condition, at both the CWS and MWS. The reduction in the V˙o2 cost during the with-assistance condition, relative to the without-assistance condition, was 7.06% at the CWS and 10.52% at the MWS.

Conclusions: The automated stride assistance device is useful for reducing energy expenditure during walking in healthy adults. Further studies are warranted to investigate if this device provides substantial help to individuals with impaired mobility as a result of strength deficits.
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http://dx.doi.org/10.1016/j.apmr.2014.07.008DOI Listing
November 2014
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