Kotaro Asanuma

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It has been proposed that deep brain stimulation (DBS) of the subthalamic nucleus (STN DBS) and dopaminergic therapy ameliorate the symptoms of Parkinson's disease through similar functional mechanisms. We examined this notion using PET to compare the metabolic effects of these treatment approaches. Nine Parkinson's disease patients (age 61.7 +/- 11.1(More)
Charcot-Marie-Tooth disease type 1A (CMT1A) is commonly considered a prototype of a hereditary demyelinating polyneuropathy. Apart from the myelin involvement, there has been little information on axonal membrane properties in this condition. Taking advantage of the uniform nature of the disease process, we undertook the in vivo assessment of multiple(More)
Somatosensory-evoked potentials (SEPs) are attenuated by movement. This phenomenon of 'gating' reflects sensorimotor integration for motor control. The frontal N30 component after median nerve stimulation was shown to be reduced in amplitude prior to hand movement. To investigate the mechanism of this sensory gating, we recorded median SEPs immediately(More)
We compared the metabolic and neurovascular effects of levodopa (LD) therapy for Parkinson's disease (PD). Eleven PD patients were scanned with both [15O]-H2O and [18F]-fluorodeoxyglucose positron emission tomography in the unmedicated state and during intravenous LD infusion. Images were used to quantify LD-mediated changes in the expression of motor- and(More)
OBJECTIVE To optimize the clinical uses of repetitive transcranial magnetic stimulation (rTMS), we compared the effects of rTMS on somatosensory-evoked potentials (SEPs) and regional cerebral blood flow (rCBF) using different phases (monophasic vs. biphasic) or frequencies (0.2Hz vs. 0.8Hz) of stimulation. METHODS In the first experiment, different phases(More)
We used [(18)F]-fluorodeoxyglucose and positron emission tomography to determine a discrete cerebral pattern of abnormal glucose utilization in dopa-responsive dystonia. Network analysis demonstrated that dopa-responsive dystonia is associated with a specific pattern of regional metabolic covariation, characterized by increases in the dorsal midbrain,(More)
In order to investigate the transcallosal effects of repetitive transcranial magnetic stimulation (rTMS), we studied median somatosensory evoked potentials (SEPs) before and after applying monophasic very low-frequency (0.2 Hz) subthreshold rTMS over the right motor cortex. For SEPs, median nerve was stimulated on each side. Sham rTMS served as the control.(More)
Functional neuroimaging, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), provides a valuable technique for detecting regional changes in brain metabolic activity associated with human disease. These techniques have been applied in different dystonic disorders including primary generalized dystonia and(More)
BACKGROUND Recently, new electrophysiological ALS criteria incorporating fasciculation potentials (FPs) as evidence for lower motor neuron signs (Awaji Criteria (AC)) was proposed to provide earlier detection of early-stage ALS than revised El Escorial electrophysiological criteria (REEC). However, serial electrophysiological analysis is lacking to(More)
Somatosensory evoked potentials (SEPs) are attenuated or gated during movement. The mechanism for this includes both centrifugal gating of afferent input and competition with other afferents caused by the movement (peripheral gating). Using a paradigm in which the signal for triggering movement is the electric stimulus for SEPs, we studied the gating of(More)