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Biomedical subjects

K Mizukoshi

Publications and source records attributed to K Mizukoshi.

At least 19 recordsLinked to original sources
PubMed1992

The relationship between smooth and saccadic components in smooth pursuit.

Eye movements in smooth and pathological (saccadic and ataxic) pursuit patterns were separated by the use of the inverse fast Fourier transform. Results showed that the smooth component was significantly smaller while the saccadic component was significantly greater in the pathological pursuit patterns than in the smooth pursuit pattern. In addition, the smooth and saccadic components showed a linear relationship. These findings give some support to the threshold theory in explaining the relationship between smooth pursuit and saccades.

Adaptation, Physiological↗
PubMed1992

Vascular cross-compression of the VIIth and VIIIth cranial nerves.

A 53-year-old male patient had been suffering from severe aural symptoms (pulsatile right-sided tinnitus and paroxysmal dizziness attacks with nausea) and right hemifacial spasm. Treatment had involved stellate ganglion block with lignocaine and the injection of intravenous sodium bicarbonate solution for attacks of Menière's syndrome and facial nerve block with lidocaine for hemi-facial spasm. Despite these treatments, the dizzy attacks became more frequent, developing into the clustering state. Air CT cisternography and vertebral angiography demonstrated an enlarged and curved vertebral artery. Vascular cross-compression of the VIIth and VIIIth cranial nerves was therefore suspected. Microvascular decompression was performed. After operation, the pulsatile tinnitus, dizziness and hemifacial spasm disappeared. From the present case and a review of the literature, we conclude that vascular cross-compression of the VIIIth cranial nerve should be an indication for microvascular decompression only when symptoms of vascular cross-compression of the VIIth cranial nerve are also seen.

Facial Nerve↗
PubMed1992

Initiation of sinusoidal tracking eye movements in man.

Smooth pursuit eye movement was recorded with a DC amplifier during horizontal sinusoidal target motion at 0.3, 0.6, 0.8, 1.0 and 1.2 Hz and a peak-to-peak amplitude of 20 degrees. Eye movement was digitalized at 100 Hz and 12 bits. From the digitalized eye movements, the maximum position error, the correlation coefficient and regression coefficients between stimulus and eye position were calculated in each half cycle. The A/D conversion and calculation were performed using a 16 bit microcomputer (NEC PC 98). Thirteen healthy volunteers with normal smooth pursuit patterns were examined. The correlation coefficient increased, but the maximum position error and the two regression coefficients decreased as the target moved. However, all four stabilized from about the 3rd half cycle regardless of the target frequency. These findings indicate that the smooth pursuit of a sinusoidally moving target reaches the maintenance at about the 3rd half cycle after initiation of two half cycles from the beginning of the target motion. This might be due to a prediction (or learning) of periodicity.

Adult↗
PubMed1991

Otoneurological manifestations of the Shy-Drager syndrome.

Three patients with the chief complaints of dizziness while standing up or blackouts were diagnosed correctly as having the Shy-Drager syndrome at the Department of Otolaryngology. Both the electrocardiogram R-peak to R-peak interval and the Schellong test revealed disorders of the autonomic nervous system in each of these cases. Electronystagmography also demonstrated pathology of the oculomotor system and/or central vestibular system. Postural balance was also abnormal in one of the cases. Auditory brain-stem responses were normal in all three cases.

Electrocardiography↗
PubMed1991

Cerebral autoregulation in patients with orthostatic hypotension.

The present study was conducted to determine the relationship between autonomic nervous function and cerebral autoregulation in 17 patients with vertigo or dizziness. Autonomic nervous function was examined by measuring systolic blood pressure response and dynamic electrocardiogram R-peak to R-peak response upon standing up. Regional cerebral autoregulation was examined by comparing cerebral blood flow in both supine and standing positions with single photon emission computed tomography. Moreover, the relationship of each of these three measures to postural provocation of symptoms was studied. The findings indicated that autonomic nervous dysfunction does not influence cerebral autoregulation, but autonomic nervous dysfunction was related to postural provocation of symptoms. This might indicate that impaired autoregulation in the brain stem or the peripheral vestibule, which could not be detected by the single photon emission computed tomography, played a role in inducing vertigo or dizziness in patients with orthostatic hypotension.

Adult↗
PubMed1991

Involvement of the VIIIth cranial nerve and the brainstem in patients with hemifacial spasm.

Twenty-seven patients with hemifacial spasm underwent neurotological (auditory and equilibrium) examinations to evaluate the VIIIth cranial nerve and/or brainstem involvement. Radiological examinations were performed to evaluate the underlying abnormalities. Twenty patients had abnormal neurotological findings, with the VIIIth cranial nerve involvement being suggested in 10 and brainstem involvement in the other 10. Radiological examinations indicated that vascular abnormalities could be detected more often in the patients with brainstem involvement than in those with VIIIth cranial nerve involvement.

Brain Stem↗
PubMed1991

Scanning electron microscopy and immunoglobulins of the endolymphatic sac in Menière's disease.

SEM and immunoglobulin staining of the intradural portion of the endolymphatic sac (ES) were investigated. All 15 normal subjects, from fetuses to an 80-year-old adult, showed well arranged epithelial cells. In Menière's disease (all 15 patients) the ES showed various types degeneration of the epithelial cells. Inner ear deafness experimentally produced by kanamycin injection showed a similar degeneration of the ES. IgG of the ES in Menière's disease showed moderately evident deposits compared with normal subjects. However, these findings were also found to the same degree as IgG deposits in animal deafness produced by KM injection. From the above results it can reasonably be concluded that the degenerated findings of the ES and deposits of the IgG in Menière's disease may possibly be the result of cochlear deafness.

Adult↗
PubMed1991

Eye movement control by Purkinje cell/climbing fiber zones of cerebellar flocculus in cat.

Direction of eye movement evoked by unilateral stimulation of the cerebellar flocculus was investigated by a video system with frame memory in ketamine-anesthetized cats. Stimulation of the Purkinje cell zone in the vertical-plane unit on the right side evoked depression of both eyes combined with intorsion of the contralateral eye and extorsion of the ipsilateral eye, and stimulation in the horizontal-plane unit evoked abduction of the ipsilateral eye and adduction of the contralateral eye.

Animals↗
PubMed1991

Influence of vestibular and visual climbing fiber signals on Purkinje cell discharge in the cerebellar nodulus of the rabbit.

Extracellular recordings of the climbing fiber responses (CFRs) of single Purkinje cells were made in the cerebellar nodulus and ventral uvula of anesthetized pigmented rabbits. Natural vestibular and optokinetic stimuli were used to evoke responses from these Purkinje cells. Using a null response technique we sorted vestibularly-evoked CFRs into two canal-related categories. CFRs were related to either the ipsilateral anterior and contralateral posterior semicircular canal (iAC+cPC) or to the ipsilateral posterior and contralateral anterior semicircular canal (iPC+cAC). Both canal-related CFRs also responded to downward optokinetic stimulation.

Acceleration↗
PubMed1991

Analysis of smooth pursuit by the fast Fourier transform.

Eye movement during smooth pursuit examination was converted to digital values and analyzed by the fast Fourier transform (FFT). It was found that the power spectra differences between the eye and target movements at 0.3 Hz were significantly lower in the pathological pursuit patterns (saccadic and ataxic pursuit patterns). In addition, sums of the power spectra difference above 0.3 Hz were significantly greater in pathological pursuit patterns.

Ataxia↗
PubMed1991

Otoneurological findings in inner ear syphilis.

Eighty-one ears in 48 patients who had had ear syphilis for the past ten years were studied and otoneurological examinations reviewed. Twenty-five of 48 cases complained of vertigo, 13 of giddiness and/or unsteadiness, and 10 cases denied dizziness. Approximately one half of the patients had abnormal findings on primary equilibrium examinations, such as Mann's test and stepping test. Spontaneous nystagmus and positional nystagmus were frequently seen on electronystagmographic examinations. Many patients showed abnormal responses to the bithermal caloric test and pendular rotation (VOR) test. Moreover, 5 of 8 patients had positive furosemide VOR tests. On transtympanic electrocochleography, 13 of 22 ears demonstrated a dominant -SP response. Eleven of 26 ears had positive findings on an intravenously administered glycerol test. In conclusion, some cases of inner ear syphilis show the characteristic findings of endolymphatic hydrops.

Adult↗
PubMed1991

A clinical study of electrocochleography in Menière's disease.

Electrocochleography (ECochG) of 168 ears with definite Meniere's disease was studied. The results were compared with recordings from 29 normal ears and 444 ears with other types of sensorineural hearing loss. It is shown that the SP/AP ratio is much more useful than SP amplitude for detecting endolymphatic hydrops. There was little difference in the mean values of SP/AP from those proposed by many other investigators; the mean values all being near 0.25. From 0.30 to 0.40 of SP/AP was considered adequate as the upper limit. Following intravenous administration of glycerol, a significant decrease in SP/AP was found in 21 Meniere's ears. However, there was no change of SP/AP after oral administration of glycerol and isosorbide. This difference may be due to the fact that a larger oral than intravenous administration is necessary to affect SP/AP. Although a postoperative decrease of 10% or more in SP/AP was observed in 5 patients, 10 patients followed up for 2 years or more after surgery did not show a statistically significant change of SP/AP and pure tone threshold. ECochG should be repeatedly recorded to be useful as a monitor for the presence of hydrops. It is discussed whether biochemical or mechanical changes in endolymph may cause a decrease in SP/AP after the use of dehydrating agents and endolymphatic sac surgery.

Audiometry, Evoked Response↗
PubMed1990

Difference between visual feedback and visual suppression upon the stabilization of body sway in normal subjects.

We developed a system to feedback the center of foot pressure by vision using a microcomputer. The subjects were instructed to adjust the center of foot pressure (displayed on the computer display at real time) to the point of intersection of the two stable (horizontal and vertical) lines on the computer display. The peak of the power spectra of body sway shifted significantly to the higher frequency range in the Y component (the lateral direction) in the visual feedback condition. Thus, we conclude that the visual feedback of body sway depends mainly on the error signals between the fovea and the image in the lateral direction to stabilize body sway.

Adult↗
PubMed1990

Blood pressure abnormalities as background roles for vertigo, dizziness and disequilibrium.

In 3 years, a total of 1,291 patients have undergone equilibrium examinations because of vertigo, dizziness and disequilibrium in the Otoneurological Division of Toyama Medical and Pharmaceutical University. Abnormal blood pressures (hypertension, hypotension and orthostatic hypotension) were found in 18.67% (241 patients). Hypotension was found significantly more often in peripheral vestibular disorders and hypertension in central nervous system disorders. Furthermore, the incidence of orthostatic hypotension was statistically higher in hypertensive patients than in hypotensive patients. Therefore, we conclude that blood pressure measurement by the Schellong test method in patients with vertigo, dizziness and disequilibrium is very important.

Adolescent↗
PubMed1989

Retro-labyrinthine disorders detected by galvanic body sway responses in routine equilibrium examinations.

Galvanic stimulation applied to the head provides important information for differential diagnosis between inner ear and retro-labyrinthine disorders of the vestibular system. So far, galvanic stimulation has been difficult to introduce in routine practice because of side effects such as severe pain around the electrode area. We have developed a new method to record fine body sway elicited by low current stimulation of less than 0.4 mA and to quantitatively evaluate the responses by Fourier transform. During the past 5 years, 502 patients, showing uni- or bilateral canal paresis in the caloric test or findings of central disequilibrium, were tested by this method without producing any side effects. In 122 patients (24.8%), such as sudden deafness, acoustic tumour, vascular disorders of the CNS system and so on, findings of retro-labyrinthine disorders were detected. It has been concluded that this method was easy to perform and very useful for differential diagnosis of diseases of the vestibular system.

Aged↗
PubMed1989

Neurotological follow-up studies upon Minamata disease.

During 1986-87, 35 patients with organic mercury intoxication, who had been recognized as having Minamata disease by the Arbitration Committee in Niigata during 1968-78, were followed up neurotologically in Kido Hospital, Niigata, Japan. Characteristic follow-up features were served, as follows. 1. In 6 cases, spontaneous nystagmus had disappeared, but had newly appeared in 9 cases. However, positional nystagmus was markedly improved in 15 cases. 2. In OKN tests, especially in the vertical OKN test, relatively significant deterioration was observed at the follow-up examinations. 3. There was little significant change in the caloric nystagmus test and body-equilibrium tests. 4. In pure-tone audiometry, 16 out of 58 ears showed deterioration of hearing (28%), while 4 ears showed improvement (7%). In the neurotological findings there was much variation among the patients themselves. Therefore, these variable findings should be considered as being caused not by duration of the intoxication alone, but also by ageing factors in the patients.

Adult↗
PubMed1989

The furosemide VOR test for Menière's disease. A preliminary report.

In order to easily detect endolymphatic hydrops and to avoid the side effects, we applied a furosemide VOR test in 24 patients with unilateral Meniere's disease, 6 patients with delayed endolymphatic hydrops, and 2 patients with labyrinthine syphilis. Immediately preceding an i.v. injection of 20 mg furosemide, and then 30, 60, 90 min after the administration, the VOR test was repeatedly performed. The slow-phase velocity in the VOR test was measured during harmonic sinusoidal rotation with eyes closed. Increased or decreased VOR-DP% beyond the normal range (10%) was referred to as positive. In 13 out of 24 cases (54%) with Menieres's disease, positive results were observed. Moreover, 4 out of 6 (67%) with delayed endolymphatic hydrops, one case out of 2 with labyrinthine syphilis were also positive in the furosemide VOR test. From these clinical investigations, we have concluded that the furosemide VOR test appeared to be another type of clinical test for the detection of vestibular endolymphatic hydrops.

Adult↗