Masashi Kamoda

Kagawa University, Takamatsu-shi, Kagawa-ken, Japan

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Publications (10)9.58 Total impact

  • No preview · Article · Oct 2002 · Nihon Naika Gakkai Zasshi
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    ABSTRACT: A number of patients with Parkinson's disease (PD) and multiple system atrophy (MSA), in whom sudden death does occur occasionally, have QT or rate-corrected QT (QTc) interval prolongation on electrocardiogram (ECG). Although these QT or QTc interval abnormalities are likely related to autonomic dysfunction, the pathophysiology remains unknown. The aim of this study was to compare the degree of QTc interval prolongation among akinetic-rigid syndromes, namely PD and related disorders, and to evaluate the relationship between QTc prolongation and severity of autonomic dysfunction. Thirty-four patients with PD, 22 with MSA, 11 with progressive supranuclear palsy (PSP) and 30 healthy controls underwent standard autonomic function tests, and electrocardiography variables (RR, QT and QTc intervals) were measured by an ECG recorder with an automated analyzer. The relationship between QTc interval and cardiovascular reflex tests were also analyzed. Orthostatic hypotension and decreased heart rate in response to respiratory stimuli were prominent in MSA, while these were relatively mild in PD. Unlike the RR and QT intervals, the QTc interval significantly differed among all groups (p<0.01). The QTc interval was significantly prolonged in PD (409+/-17 ms; p<0.001) and MSA (404+/-14 ms; p<0.05) compared with healthy controls (394+/-19 ms). Neither autonomic dysfunction nor QTc interval prolongation was evident in PSP. QTc intervals and cardiovascular reflexes did not correlate, except for Valsalva ratio. The QTc interval was obviously prolonged in PD patients to an extent that could not be accounted for simply by autonomic dysfunction levels. MSA patients showed slightly prolonged QTc intervals in spite of marked cardiovascular autonomic dysfunction. Abnormalities of the QTc may reflect the degeneration of cardioselective sympathetic and parasympathetic neurons that cannot be fully captured by cardiovascular autonomic function tests.
    No preview · Article · Jul 2002 · Journal of the Neurological Sciences
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    ABSTRACT: To evaluate median nerve somatosensory evoked potentials (SEPs) and alpha waves during different eye conditions. Median SEPs and occipital electroencephalographs (EEG) were recorded in 6 eye conditions: eye-closed (EC), goggle (G), goggle+saccade (GS), saccade (S), eye-opened (EO) and pursuit (P), in 8 normal adults. Subjects saccaded their eyes reacting to auditory cues to watch a diode on the right or left side alternatively during the S condition, or imitated the same saccadic eye-movement as that in the S condition during the GS condition. In the P condition, subjects traced a small circle moving on a computer screen. Compared with the EC and G conditions, N30 (P25-N30 or P14-N30) amplitudes in C4' were significantly larger and the mean amplitude and power of the alpha band was significantly attenuated in the other 4 conditions. The amplitude and power of the alpha band differed significantly between the GS and S conditions, whereas N30 amplitudes were similar between the two conditions. N30-P45 or P45-N60 amplitudes in C4' were significantly larger in the P condition than in other conditions. Present findings suggest that different neural mechanisms cause alpha blocking and the modification of middle latency SEPs associated with oculomotor control.
    No preview · Article · Jan 2002 · Clinical Neurophysiology
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    ABSTRACT: The effects of chronic L-dopa administration on antidromic excitability and the firing rate of nigrostriatal dopaminergic neurons were investigated in urethane-anesthetized rats. Rats that received daily L-dopa (100 mg/kg) and carbidopa (25 mg/kg) for 60 days showed a marked decrease in terminal excitability compared with the controls. There were no significant differences in the firing rates between the two groups. This finding may be related to impaired striatal dopamine release from exogenous L-dopa subsequent to chronic L-dopa treatment.
    No preview · Article · Jun 1999 · Neuroscience Research

  • No preview · Article · Jan 1999 · Comparative biochemistry and physiology. B, Comparative biochemistry
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    ABSTRACT: A 37-year-old man with alcoholic polyneuropathy showed involuntary movement as intermittent flexion-extension or abduction-adduction of his toes identical to "painful legs and moving toes (PLMT)" and muscle cramps. Regarding the sequential spreading of PLMT and cramps from unilateral to contralateral leg muscles and phasic discharges observed by a needle EMG in the foot muscles during PLMT, we suppose that a spinal or supraspinal mechanism was responsible for the production of those movements. This case showed novel aspects of PLMT which was induced by sensory stimulation of the left lower leg and subsequently initiated cramps. The destruction of the lumbar sympathetic ganglion remarkably ameliorated the spontaneous PLMT and cramps, whereas sensory stimulation of the left lower leg still induced those movements. Therefore, we think that sensory inputs from peripheral nerves played a critical role in the generation of PLMT and cramps, and abnormal activities of spinal sympathetic nerves exacerbated those involuntary movements. Sensory induced PLMT may be a subgroup of this movement disorder.
    No preview · Article · Sep 1998 · Rinsho shinkeigaku = Clinical neurology
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    ABSTRACT: The sympathetic skin response (SSR) is used as an index of sudomotor sympathetic function. However, the central processing of this response is not fully understood. To clarify this point, we assessed the relevance of cognitive function in the elicitation of SSR in 14 healthy subjects by recording simultaneously the somatosensory event-related potential (ERP) and SSR evoked by electric stimuli. The ERP paradigm consisted of three types of stimuli, task-relevant target, task-irrelevant electric shock which is equivalent to the common stimulus for eliciting SSR, and task-irrelevant standard stimuli. ERPs were recorded at Fz, Cz, and Pz on the scalp, SSRs were recorded in both palms and soles of the subject after each stimulus in the ERP paradigm. Target stimuli generated a P300 (P3b) and elicited a variety of SSRs from subject to subject. Electric shock stimuli generated a novelty P300 with a shorter peak latency and a higher amplitude than the P3b, with stable elicitation of SSR in the four limbs of all subjects. P300 amplitude showed a significant positive correlation with SSR amplitude with electric shock stimuli. This correlation predominated in the frontal region (Fz), as compared with the parietal region (Pz). A negative correlation between P300 latency and SSR amplitude with electric shock stimuli was also observed. These findings indicate that the elicitation of SSR is influenced by the generation of novelty P300, that is, cognitive function. The frontal region may play a key role in the elicitation of SSR. We believe that the assessment of novelty P300 is required for a precise interpretation of the SSR.
    No preview · Article · Dec 1996 · Journal of the Autonomic Nervous System

  • No preview · Article · Sep 1995 · Electroencephalography and Clinical Neurophysiology/Electromyography and Motor Control
  • K Sato · H Takeuchi · M Kamoda · T Touge · A Yamada · M Nishioka
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    ABSTRACT: Abnormal event-related potential (ERP) has been reported in several types of dementing illness including Parkinson's disease (PD) and progressive supranuclear palsy (PSP). In this paper we report the result of EPR recordings obtained in normal control subjects (14 cases) and in patients with PSP (6 cases) and PD (32 cases). ERPs were recorded from 13 scalp electrodes, using the acoustic odd-ball paradigm. All PD patients were in early stage (Yahr stage 1 to 2), and all PSP patients were in the mild-to-moderate state. In control subjects and PD patients P3 was normal. In PSP patients, only one subject (17%) showed a normal P3 component, three cases (50%) demonstrated low amplitude and normal latency P3, and two cases (33%) featured lack of normal P3 sequence. The P3 abnormalities in PSP patients were not related with dementia, but with low amplitude P3 being observed in 2 of 3 non-demented patients, and abolished P3 in a patient with only mild dementia. The result suggests that the P3 changes in PSP patients develop earlier than the cognitive dysfunction, and they are related to the underlying subcortical lesion rather than dementia.
    No preview · Article · May 1993 · Rinsho shinkeigaku = Clinical neurology
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    ABSTRACT: Central alveolar hypoventilation syndrome (CAH), or Ondine's curse, is a very rare disease characterized by dysfunction of respiratory center in the brain stem. Here, we report a case of CAH associated with cerebral infarction. A 59-year-old man developed right facial sensory deficit at age 56. Then, the facial sensory deficit spread to the left side and dysarthria and dysphagia also developed. Since age 58, he often developed respiratory failure and consciousness disturbance. Arterial blood gas analysis revealed alveolar hypoventilation and respiratory acidosis. Disorders of peripheral organs such as lung, airway, thorax and neuromuscular diseases were ruled out. Brain MRI showed cerebral infarction in the brain stem. We diagnosed him as CAH associated with brain stem infarction.
    No preview · Article · Apr 1993 · Nō to shinkei = Brain and nerve