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Biomedical subjects

H Shibasaki

Publications and source records attributed to H Shibasaki.

10 recordsLinked to original sources
PubMed1979

Oculomotor abnormalities in Parkinson's disease.

Ocular movement was studied in 19 patients with Parkinson's disease and in ten normal controls. Common abnormalities included "hypometric saccade" on the eye-tracking test and on command, "saccadic pursuit," and convergence paresis. Reaction time was longer in patients with Parkinson's disease than in controls for horizontal saccadic gaze, finger movements, and body movements. Maximal saccadic velocity of horizontal gaze was slower in patients with Parkinson's disease than in controls. Slowing of the horizontal saccadic movement correlated significantly with an increased reaction time of finger and body movements. Correlation of decreased saccadic velocity with increased reaction time of finger movement was found for the finger ipsilateral to the direction of horizontal gaze, but not for the contralateral finger. It is postulated from these facts that bradykinesia also exists in eye movements in Parkinson's disease.

Aged↗
PubMed1979

Pigmentary degeneration of the retina in heredodegenerative neurological diseases.

Frequency of pigmentary degeneration of the retina (PDR) among patients with degenerative and heredodegenerative neurological diseases (HDNDs) was estimated based on the hospital statistics. PDR was detected in 3% of 176 inpatients with HDNDs by careful ophthalmologic examination. On the other hand, out of 30 consecutive cases of PDR seen in our Department of Neurology, 15 patients were associated with some form of HDNDs. Atypical PDR were more frequently associated with HDNDs than typical PDR. Among neurological manifestations in those 15 cases of PDR associated with HDNDs, mental deficiency, hearing disturbance, spasticity, progressive ophthalmoplegia and ataxia were most frequently encountered. Four cases with unusual symptomatology were presented. Clinical analysis of cases of PDR associated with HDNDs in the present series as well as in the relevant literature revealed an extreme variety of clinical manifestations and underlying metabolic disorders, suggesting a possible participation of multiple factors in the pathogenesis of PDR. Importance of careful ophthalmologic examination in HDNDs was stressed from the prognostic point of view.

Adolescent↗
PubMed1978

Clinical studies of the movement-related cortical potential (MP) and the relationship between the dentatorubrothalamic pathway and readiness potential (RP).

In order to investigate the influence of basal ganglia and cerebellar involvement on the preparatory state of the cerebral cortex for voluntary movement, the cortical potential preceding finger movement was studied in 20 patients with Parkinson's disease and 20 patients with cerebellar ataxia. Readiness potential (RP) was abnormal in 90% of the Parkinson group and in 55% of the cerebellar ataxia group. The most frequent abnormality was a depressed amplitude and earlier onset of RP in both groups. The most remarkable finding in the present study was the complete absence of RP with dyssynergia cerebellaris myoclonica (presumed Ramsay Hunt syndrome) whereas normal RP was obtained with cerebellar cortical degeneration. In addition, RP was absent or severely depressed in patients with a unilateral vascular lesion of the midbrain (Benedikt's syndrome) and in patients with Parkinson's disease who underwent unilateral intermedioventral (Vim) thalamotomy. These facts suggest a possible important role of the dentatorubrothalamic or dentatothalamic pathway in the physiogenesis of RP.

Adolescent↗
PubMed1978

Electroencephalographic studies myoclonus.

Electroencephalographic studies were carried out in 30 patients with various kinds of myoclonus. It was confirmed that the technique of jerk-locked averaging with a backward averaging program was useful for detecting cortical spikes in association with the spontaneously occurring myoclonus, which are not recognized on the convential polygraph, and for evaluating the temporal and topographical relationship between the spike and the myoclonus. By this technique, cortical spikes were shown to precede the myoclonus of a contralateral upper extremity muscle by 7 to 15 ms ith progressive myoclonic epilepsy showed a high amplitude somatosensory evoked potential (SEP) in response to electrical stimulation of the median nerve. The N33 component of this high amplitude SEP was found to be similar to the myoclonus-related cortical spike in their wave form, time relationship and topographical distribution, suggesting an involvement of similar physiological mechanisms in the genesis of both phenomena. Myoclonus in these patients is compatible with "pyramidal" or "cortical loop reflex" type.

Adolescent↗
PubMed1978

Multiple sclerosis among Orientals and Caucasians in Hawaii: a reappraisal.

A comparative retrospective study of Oriental and Caucasian patients with multiple sclerosis (MS) failed to reveal significant differences between the two groups regarding historical data, such as sex ratio, mode of onset, age at onset, duration of illness, and clinical course, suggesting that MS is essentially the same disease in both groups. However, certain clinical features were more frequent in Orientals: Severe bilateral optic nerve involvement; acute transverse myelopathy, especially of a recurrent nature; clear-cut sensory levels; and optic-spinal-brainstem and optic-spinal involvement. Environmental factors may also be responsible.

Adult↗
PubMed1975

Movement-associated cortical potentials in unilateral cerebral lesions.

Movement-associated cortical potentials (MP) associated with thumb-opposition or fist-clenching were studied in 20 patients with unilateral cerebral lesions and in 8 healthy subjects. MP was abnormal in 16 patients. The most frequent abnormality was an attenuation of the N component or readiness potential, recorded on the central region contralateral to the contracting muscle, on the affected hemisphere. The occurrence and severity of MP abnormalities seem to be influenced by an intensity and extension of the lesion, rather than by how much disability is present in the affected limb. There was no significant correlation between the abnormalities of MP and of EEG. The most useful index of MP for comparing two hemispheres was shown to be the amplitude and wave form of the N component or readiness potential contralateral to the contracting muscle.

Adolescent↗
PubMed1975

Movement-associated cortical potentials with unilateral and bilateral simultaneous hand movement.

Cortical potentials associated with unilateral and bilateral simultaneous thumb opposition were studied in 9 healthy subjects. The P1 component, "pre-motion positivity", was recognized in 5 out of 9 subjects on unilateral thumb movement. In all subjects in whom P1 was recognized, P1 was dominant over the cerebral hemisphere ipsilateral to the contracting muscles. On bilateral simultaneous thumb movement, however, P1 was not discerned in any subject. This is compatible with the assumption that P1 is related to an inhibition of imitative movement of the opposite hand (mirror movement). The N2 component had its onset after the start of muscle contraction in most cases, suggesting that N2 might not reflect activation of the corticospinal pathways.

Adult↗
PubMed1975

Electroencephalographic correlates of myoclonus.

In order to overcome various drawbacks of the conventional polygraphic study of a relationship between myoclonus and EEG, the EEG preceding and following the myoclonic jerk was simultaneously averaged by the CNV program. The subjects were 7 patients presenting with myoclonus of various kinds. The conventional polygraphs showed various paroxysmal EEG activities in 4 patients, but none of those paroxysmal activities was temporally related to myoclonus except for one case. As a result of the present averaging technique, 2 patients with cerebellar ataxia with intention myoclonus showed myoclonus-related EEG spikes or spike-and-slow-waves in the contralateral central or centroparietal region. These myoclonus-related spikes preceded the myoclonus by 10-17 msec, suggesting the presence of a discharging focus in the deep cerebral structures, rather than in the cerebral cortex, in these cases. Two other patients, one with resting myoclonus and the other with postural myoclonus, showed myoclonus-related slow waves on the contralateral hemisphere. This previously undescribed method of averaged polygraphic recording will be very useful in detecting an EEG correlate of spontaneously occurring myoclonus.

Adolescent↗