Yoshihisa Masakado

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OBJECTIVE We examined the time at which loss of functioning motor units occurs on the hemiparetic side, the relationship between that loss and hemiparetic severity, and how long that loss continues. METHODS Sample surface motor unit action potentials (S-MUAPs) were evoked in F-waves. They entirely represent the activity of the relative numbers of(More)
The present study was designed to examine the effects of median nerve stimulation on motoneurones of remote muscles in healthy subjects using H-reflex, averaged EMG and PSTH methods. Stimulation of the median nerve induced facilitation of soleus H-reflex from about 50 ms and it reached a peak at about 100 ms of conditioning-test interval. Afferents that(More)
It is known that weak transcranial direct current stimulation (tDCS) induces persistent excitability changes in the cerebral cortex. There are, however, few studies that compare the after-effects of anodal versus cathodal tDCS in patients with stroke. This study assessed the after-effects of tDCS over the motor cortex in patients with hemiparetic stroke and(More)
BACKGROUND AND OBJECTIVE We devised a therapeutic approach to facilitate the use of the hemiparetic upper extremity (UE) in daily life by combining integrated volitional control electrical stimulation with a wrist splint, called hybrid assistive neuromuscular dynamic stimulation (HANDS). METHODS Twenty patients with chronic hemiparetic stroke (median 17.5(More)
OBJECTIVE To investigate motor unit synchronization in the time and frequency domains and compare the amount and nature of this synchronization between upper and lower extremity muscles in human subjects. METHODS A total of 120 motor unit pairs from biceps brachii (BB), first dorsal interosseous (1DI), vastus medialis (VM), and tibialis anterior (TA) on(More)
We determined the changes and responses in the electroencephalogram (EEG) induced by transcranial magnetic stimulation (TMS) of the scalp of five healthy men. The center of a circular coil was positioned at the vertex, and 80 stimulations were administered clockwise with the maximum output of electric current. To reduce stimulus artifacts, we created a(More)
Cortico-muscular coherence was compared during ramp-and-hold isometric and quasi-isotonic contraction of the ankle joint in human subjects. EEG was recorded from the leg area of the motor cortex. EMG was recorded from the tibialis anterior (TA) muscle. The subjects were requested to maintain a steady low level of dorsiflexion and at intervals of 10 s to(More)
OBJECTIVE To investigate the left-right difference and the reproducibility by the F-wave motor unit number estimation and to compare the motor unit number between the hemiplegic and unaffected side in stroke patients. SETTING A referral center and institutional practice providing outpatient care. SUBJECTS Seven healthy volunteers and 15 consecutive(More)
PURPOSE Recent studies have investigated the possible function of synchronous oscillatory activity within the sensorimotor cortex of monkeys and humans that is thought to arise from synchronous discharge of large numbers of cortical neurons. There has been found clear task-dependent changes in 15-30 Hz oscillations. In leg muscles, coherence also occurs in(More)
The sensorimotor cortex activity measured by scalp EEG shows coherence with electromyogram (EMG) activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate intensity of isometric voluntary contraction. This coupling is known to change its frequency band to the 35- to 60-Hz band (γ-band) during strong contraction. This study aimed to(More)