Biomedical subjects

H Shojaku

Publications and source records attributed to H Shojaku.

At least 19 recordsLinked to original sources

PubMed2001

Ménière's disease and delayed endolymphatic hydrops in children.

In order to study the characteristics of pediatric patients (< or = 15 years at onset) with endolymphatic hydrops disorders, we selected 5 patients with Ménière's disease (MD) and 3 patients with delayed endolymphatic hydrops (DEH) from 7418 patients who had visited the Neurotological Clinic of the Toyama Medical and Pharmaceutical University Hospital between 1979 and 1999. Clinical features were characterized as follows: (i) pediatric MD patients were rare, comprising approximately 1.5% of all the 337 MD patients in the sample; (ii) a fluctuating hearing loss, strong positive response in glycerol test, high SP/AP amplitude ratio in electrocochleography and moderate positive response in furosemide vestibulo-ocular reflex test were recorded; (iii) in 2 of the 5 pediatric MD patients, vertiginous attacks had persisted for a long period and they had undergone surgical procedures (sac operation and vestibular neurectomy); and (iv) the ipsilateral type of DEH was observed in 2/3 children, and contralateral DEH in 1/3.

Adolescent↗

PubMed2001

Clinical usefulness of glycerol vestibular-evoked myogenic potentials: preliminary report.

The detection of intense sound-induced vestibular-evoked myogenic potentials (VEMPs) on the sternocleidomastoid muscle comprises the basis of the saccular function test. In order to evaluate the endolymphatic hydrops (EH) of the saccule of the inner ear, a glycerol VEMP (GVEMP) test was performed in 15 patients with unilateral typical Ménière's disease (UMD) and 7 with delayed endolymphatic hydrops (DEH). Using the GVEMP test, 8 of the 15 patients (53%) with UMD were evaluated as being abnormal. In addition, a greater number of patients (67%) were judged to be abnormal when the results of the GVEMP test were combined with those from a glycerol dehydration test, trans-tympanic electrocochleography (ECochG) or furosemide vestibulo-ocular reflex test (FVOR). Four of the 7 patients with DEH (57%) showed abnormal results in the GVEMP test. In particular, in patients with the ipsilateral type of DEH, only the GVEMP test was able to detect the affected side. These findings suggest that the GVEMP test is a new and useful test for EH, and that a test battery comprising the GVEMP test together with one of the other three tests is useful for diagnosing EH of the inner ear.

Audiometry, Evoked Response↗

PubMed2000

Clinical study of elderly patients with Meniere's and related diseases.

In order to study the characteristics of elderly patients (70 or over at onset) with endolymphatic hydrops disorders, we selected six patients with Meniere's disease (MD), five patients with delayed endolymphatic hydrops (DEH), and two patients with syphilis of the labyrinth (SL) from 7112 patients who had visited the Neurotological Clinic of the Toyama Medical and Pharmaceutical University Hospital during 1979-1998. Clinical features were characterized as follows: (1) Since 1990, the proportion of elderly patients increased as lifespans lengthened. (2) A narrow fluctuation in hearing, low positive rate on glycerol test, high positive rate of dominant-SP in EcochG, and the moderate abnormal rate of the oculomotor system tests were found. (3) The prognosis was relatively good. From these neurotological observations, it could be concluded that elderly patients with endolymphatic hydrops disorders were characterized by the multipathological finding of the endolymphatic hydrops and the complications of CNS disorders.

Adolescent↗

PubMed1998

Diffusion-weighted echo-planar MRI of lacunar infarcts.

We studied 35 patients with lacunar infarcts, using diffusion-weighted echo-planar imaging (DW-EPI) at 1.5 T. The relative apparent diffusion coefficient ratio (ADCR) of each lesion was calculated and lesion conspicuity on DW-EPI was compared to that on images acquired with fast fluid-attenuated inversion recovery and T2-weighted fast spin-echo sequences. Acute small infarcts (within 3 days) were identified with DW-EPI as an area of decreased ADCR (range 0.33-0.87; mean 0.67) and high signal, subacute small infarcts (4-30 days) as a high-signal or isointense areas of decreased or nearly normal ADCR (0.54-0.98; 0.73), and chronic small infarcts (> 30 days) as low- or high-signal areas of nearly normal or increased ADCR (0.97-1.92; 1.32). In three patients, small infarcts of the brain stem in the hyperacute phase (within 6 h) were seen only with DW-EPI. In five patients, fresh small infarcts adjacent to multiple old infarcts could be distinguished only with DW-EPI.

Aged↗

PubMed1997

The prevalence of definite cases of Menière's disease in the Hida and Nishikubiki districts of central Japan: a survey of relatively isolated areas of medical care.

In order to evaluate the prevalence of definite cases of Menière's disease (MD), we performed a 1-year survey in 1994 of patients in the Hida and Nishikubiki districts, where a majority of the patients are thought to seek treatment at the medical facilities within these areas for geographical reasons. As a result of the cooperation of all ENT departments of the general hospitals and ENT clinics (general practitioners) in these districts, 67 patients were diagnosed as definite cases of MD according to the diagnostic criteria proposed by The Menière's Disease Research Committee of Japan. Annual prevalence was estimated at 36.6 per 100,000 population in the Hida district and at 21.4 per 100,000 population in the Nishikubiki district, which is higher than those reported in previous Japanese surveys.

Evaluation Studies as Topic↗

PubMed1995

Vestibular and visual climbing fiber signals evoked in the uvula-nodulus of the rabbit cerebellum by natural stimulation.

1. The cerebellar uvula-nodulus receives vestibular projections from primary and secondary vestibular afferents as well as vestibularly related climbing fibers. It also receives visually related information from climbing fiber pathways. In this experiment we investigated how this information is mapped onto the uvula-nodulus. We studied the specificity, dynamics, and topographic distribution of climbing fiber responses (CFRs), simple spike responses, and mossy fiber terminal responses evoked by vestibular and optokinetic stimulation in rabbits anesthetized with alpha-chloralose. 2. Vestibularly evoked CFRs were found in the ventral uvula and nodulus. These responses were evoked during static roll tilt of the rabbit about a longitudinal axis and by sinusoidal oscillation about the longitudinal axis. Purely static responses were attributed to stimulation of the utricular otolith by the linear acceleration of gravity. CFRs that lacked a static component were attributed to activation of the semicircular canals. 3. Using a "null technique" we showed that the canal-sensitive CFRs were caused by stimulation of the anterior or posterior semicircular canals. Of the CFRs classified as canal related, 96% could be attributed to stimulation of the vertical semicircular canals. 4. Increases in CFRs were correlated with decreases in simple spike responses in half the Purkinje cells from which we recorded. These climbing-fiber-induced pauses in simple spikes occurred during spontaneous climbing fiber discharge as well as during climbing fiber discharge evoked by vestibular stimulation. The duration of this pause was inversely proportional to the spontaneous level of simple spikes before the occurrence of a CFR. In the other half of the recorded population of Purkinje cells, vestibularly driven CFRs did not alter the simple spike responses. 5. Vestibularly and visually mediated CFRs were topographically represented on the surface of the uvula-nodulus. CFRs driven by ipsilateral otolithic inputs were distributed over the entire mediolateral surface of the uvula-nodulus. CFRs driven by the ipsilateral posterior semicircular canal were distributed in a sagittal strip approximately 1.5 mm wide, extending laterally from the midline of the nodulus. CFRs driven exclusively by horizontal, posterior-->anterior optokinetic stimulation of the ipsilateral eye were distributed in a sagittal strip approximately 0.5 mm wide located 0.5-1.0 mm from the midline and restricted to the ventral nodulus. CFRs driven by the ipsilateral anterior semicircular canal were found in a sagittal strip approximately 1.0 mm wide extending 1.0-2.0 mm from the midline. 6. The sagittal, topographically arrayed climbing fiber strips effectively map a mediolateral gradient of possible postural responses based on vestibular and optokinetic information.

Adaptation, Physiological↗

PubMed1995

Epidemiological and clinical characteristics of Menière's disease in Japan.

From 1975 to 1990, nationwide surveys on Menière's disease were performed three times by the Research Committee of Menière's disease (1975-76) and the Research Committee of Peripheral Vestibular Disorders (1982-84 and 1990) in Japan. Nine hundred and fifty-eight definite Menière cases, 520 in the 1st, 230 in the 2nd and 148 in the 3rd survey, were sampled by the members of the Committees. The epidemiological and clinical characteristics of Menière's disease were analyzed and compared with such control cases as other vertiginous patients, ENT patients without vertigo, and healthy subjects. In Menière's disease, the male to female ratio has changed from even to female predominance over the 15 years the study ran. The age distribution at onset peaked in the forties for males and thirties for females. Significant epidemiological results are summarized as follows: Definite Menière's disease has a higher incidence in married persons and in people with a nervous and precise character, whereas the incidence is lower in obese people. Physical and mental fatigue induced the onset of attacks. Menière's disease happened in day time in many cases, especially during the afternoon. As these epidemiological findings were commonly observed in all the surveys, the results are considered to be universal epidemiological characteristics of Menière's disease in Japan. In the same period, regional investigations were performed by Toyama Medical Association and our University. The male to female ratio in Toyama indicated a more significant female predominance than in the nationwide surveys. The prevalence of Menière's disease in Toyama Prefecture has been almost constant in all surveys, about 17/100,000 since 1974.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Preliminary guidelines for reporting treatment results in Menière's disease conducted by the Committee of the Japanese Society for Equilibrium Research, 1993.

In order to draft guidelines for reporting treatment results in Menière's disease (MD) in Japan, 17 committee members elected from the Japanese Society for Equilibrium Research (JSER) have met for about two years. The preliminary guidelines obtained from their discussions are summarized as follows. i) Evaluations of symptoms: Only definitive vertiginous spells with spontaneous nystagmus should be evaluated (AAOO, 1972). The parameter for the assessment of hearing levels should be evaluated using four-frequency pure-tone averages (PTA) at 250 Hz, 500 Hz, 1 kHz and 2 kHz. ii) Evaluation period: Valid results for the evaluation should be based on observations at least six months before treatment and over at least 12 months after initiation of therapy. iii) Evaluation criteria The formula expressing the effects of treatment on vertiginous spells should adopt a numeric vertigo score, which is shown in the AAO-HNS (1985) guidelines. If the duration of pre-treatment evaluation period is less than 6 months, the divisor is replaced by the average of definitive spells per month for the period of observation. iv) Global judgment: For a global judgment, patients and doctors should jointly evaluate the treatment results from the standpoints of their subjective and objective symptoms respectively.

Humans↗

PubMed1995

Influence of a cold front upon the onset of Meniére's disease in Toyama, Japan.

In order to clarify the influence of a cold front (CF) upon the onset of Meniére's disease (MD), major CFs were defined by meteorological observations, and the influence of CFs on MD was evaluated by using the time n method. From our preliminary study it was seen that the onset of MD had its highest incidence exactly on days where a CF passed by. Out of the patients with MD, sudden deafness (SD) and Bell's palsy (BP) who visited our neurotological clinic of the Toyama Medical and Pharmaceutical University from 1987 to 1992, 67 MD patients, 70 SD patients and 70 BP patients could clearly define the date of the onset of their disease, and were therefore selected for this epidemiological study. Thirty-six our of the 67 MD patients had the first attack on the day when a CF passed by or on the next day. The results obtained from these studies were as follows. i) The onset of MD was influenced by the passing of a CF, and this influence was more specific in MD than in SD or BP. ii) In the 36 CF influence MD patients, the majority were over the forty years, and their hearing level was worse than that of the other 31 MD patients during the observation periods.

Adolescent↗

PubMed1995

Epidemiological study of severe cases of Meniére's disease in Japan.

In order to clarify the characteristics of severe cases of Meniére's disease (MD), we analyzed various epidemiological factors such as sex ratio, past history, complication, cause of onset of vertiginous attacks, etc., in a series of 958 patients with definite MD. Data were obtained from the three Japan-wide surveys of MD conducted by the Meniére's Disease Research Committee of Japan (1975-76) and the Vestibular Disorders Research Committee of Japan (1982-84 & 1990). Following the ideas proposed by the members of the Vestibular Disorder Research Committee of Japan, we divided severe cases into three categories according to the following criteria i) bilateral MD cases (BMD), ii) unilateral MD cases with prolonged disabled vertigo (UPDV), iii) unilateral MD cases with profound hearing loss (UPHL). About 40% of the subjects were classified as severe cases (UPDV: 23%; BMD: 9%; UPHL: 6%). The ratio of otitis media in past history was statistically different between severe cases and non-severe patients (p < 0.05), suggesting that otitis media in the past may contribute to the severity of Meniére's disease.

Adolescent↗

PubMed1994

Visual otolith-ocular reflex in normal subjects. A preliminary report.

The influence of the otolith-ocular reflex (OOR) induced by the linear (along Y-axis) acceleration was evaluated 12 healthy subjects. The elicited maximum eye velocity (MV) was comparatively analyzed under three stimulus conditions; (1) sinusoidal linear acceleration with eyes covered, (2) sinusoidal optokinetic stimulus and (3) sinusoidal linear acceleration with eyes open (visual-vestibular interaction). By the linear acceleration level of 78 cm2, i.e. 0.08 G, the MV of the optokinetic response (OKR) showed no change in spite of the existence of the OOR.

Acceleration↗

PubMed1994

Optokinetic nystagmus elicited by a random dot pattern and a wide interval stripe pattern in normal subjects.

In optokinetic stimulus in practical living conditions, not only the central fovea but also the peripheral retina are strongly stimulated. In order to investigate the influence of this stimulus on the peripheral retina in optokinetic nystagmus (OKN), we tested OKN elicited by a pattern of numerous random dots (ROKN) in 30 normal subjects and compared the results with those of OKN elicited by a wide interval stripe pattern. The most significant difference between the two response patterns was the correlation between slow phase velocity and slow and fast phase amplitude. In ROKN, the nystagmus amplitude was highly correlated with slow phase velocity. On the other hand, in SOKN there were two types of correlation between slow phase velocity and nystagmus amplitude. One indicated low correlation, which was extremely predominant, and the other, high correlation as in ROKN. This tendency was more marked in the fast phase amplitude. Although it is generally accepted that OKN fast phase in SOKN is controlled by voluntary saccade, our results indicate that ROKN is more strongly controlled by reflective resetting eye movements, which is similar to the nystagmus fast phase in vestibular nystagmus.

Adult↗

PubMed1994

Sudden deafness from vertebrobasilar artery disorder.

Two cases are presented of sudden deafness with vertigo and/or dizziness, a 19-year-old male and a 54-year-old female. Their onset condition was considered to be caused by vascular disorders in the area of the vertebrobasilar artery, but they showed no signs of the central nervous system disorders. Case 1 suffered right sudden deafness just after a super selective embolization for the peripheral area of the right vertebral artery, and case 2, just after the accidental cutting of the left vertebral artery during the procedure of neurovascular decompression surgery. The neurotologic findings in these cases were almost the same and the common characteristics were (1) irreversible total deafness of the affected ear, (2) canal paresis in caloric test, (3) retrolabyrinthine disorder of the vestibular system detected by the galvanic test, and (4) no obvious findings of central nervous system disorders, such as eye movement disorder or ataxy. These findings indicate that the sudden deafness was attributable to localized embolism in the inner ear artery caused by thrombosis in the area of the vertebrobasilar artery.

Adult↗

PubMed1993

Vestibular primary afferent projection to the cerebellum of the rabbit.

The vestibular primary afferent projection to the cerebellum of the rabbit was studied with retrograde and orthograde tracers. We injected individual lobules of the cerebellum with horseradish peroxidase (HRP) or wheat germ agglutinin-HRP (WGA-HRP). Following these injections the numbers of labeled and unlabeled cells in Scarpa's ganglion were counted. Approximately 64-89% of the cells in Scarpa's ganglion were labeled retrogradely following uvula-nodular injections. About 2% of the cells in the ipsilateral Scarpa's ganglion were labeled after injections of the flocculus. Virtually no cells were labeled following injections of the ventral paraflocculus. The vestibular primary afferent projection to the uvula-nodulus is so extensive that it must be part of a collateral system that also innervates the vestibular nuclei. This collateral projection pattern was confirmed by using fluorescent tracers injected into the uvula-nodulus and vestibular complex. Fluorogold was injected into the uvula-nodulus and peroxidase-rhodamine isothiocyanate was injected into the vestibular complex. More than 50% of the neurons in Scarpa's ganglion were double labeled by these subtotal injections. The dense vestibular primary afferent projection to the uvula-nodulus was confirmed by using the C fragment of tetanus toxin (TTC) injected into the labyrinth as an orthograde tracer. With the TTC technique, the vestibular primary afferent projection to the uvula-nodulus terminated exclusively in the ipsilateral granule cell layer of lobules 9d and 10. Much sparser vestibular primary afferent projections were found in the banks of major cerebellar sulci. A barely detectable projection was found to the flocculus and ventral paraflocculus.

Afferent Pathways↗

PubMed1993

Activity of neurons in the beta nucleus of the inferior olive of the rabbit evoked by natural vestibular stimulation.

The inferior olive (IO) appears to be organized functionally in discrete subnuclei that receive transmitter-specific inputs. In particular, the IO receives a GABAergic input that is most densely concentrated in the beta-nucleus. In this experiment, we examined the functional specificity of neurons in the beta-nucleus of the IO of rabbits by recording their activity during natural vestibular and optokinetic stimulation. Rabbits were anesthetized and positioned in a triaxial servo- controlled rate table with the head fixed at the center of rotation. Contour-rich visual stimuli were rear-projected onto a 70 deg tangent screen and moved at constant velocities. Recording sites in the beta-nucleus were verified by subsequent histological analysis of marking microlesions. Neurons in the beta-nucleus responded to roll vestibular stimulation about the longitudinal axis. These neurons were excited when the rabbit was rolled onto the side which was contralateral to the recording site, and inhibited when the rabbit was rolled ipsilaterally. Thirty-eight of the 75 beta-nucleus neurons that were responsive to roll vestibular stimulation also responded to static tilt, indicating an otolithic as well as a vertical semicircular canal origin of the vestibular input. The modulated activity of none of the neurons could be attributed to stimulation of the horizontal semicircular canals. All the recorded neurons were found in a region of the beta-nucleus that was retrogradely labeled following HRP injections into the cerebellar nodulus. Using a "null point" technique, we found that there was a differential projection of information from the anterior and posterior semicircular canals onto to the beta-nucleus. Stimulation of the ipsilateral anterior-contralateral posterior semicircular canals modulates activity of the neurons in the caudal 500 microns of the beta-nucleus. Stimulation of the ipsilateral posterior-contralateral anterior semicircular canals modulates activity of neurons located more rostrally. beta-nucleus neurons and the olivocerebellar circuits in which they participate may constitute an important pathway for the control and adaptive modification of postural reflexes.

Action Potentials↗

PubMed1993

Clinical significance of the galvanic body sway test in cerebellopontine angle tumors.

Since 1984, we have been modifying a new method of recording fine body sway elicited by low current stimuli of less than 0.4 mA, and of quantitatively evaluating the responses by Fourier transform. In order to easily and early detect acoustic tumors, we have applied a test battery consisting ABR, caloric test and galvanic body sway test (GBST) to 31 cases with acoustic neurinoma, to 5 cases with other CPA-tumors, and to 24 cases suspected of having CPA tumors. Of 27 cases with acoustic neurinoma on whom the GBST was performed, 25 cases (92.6%) shows abnormal responses. On the other hand, the ABR was abnormal in all cases, except for one case in the early stage of an ear tumor. However, the ABR was positive in 12 cases out of 24 with suspected findings without tumor, but the GBST was positive in only 3 cases out of 17 tested. Moreover, 26 cases (83.9%) with acoustic tumors showed abnormal CP in their first caloric tests. Comparing these observations with the results of image diagnosis, we conclude that the GBST is as useful for detecting small acoustic neurinomas as the ABR and the carloric test. Therefore, we have routinely used a test battery consisting ABR, caloric test and GBST for evaluation of acoustic neurinomas. However, we could not differentiate between acoustic neurinoma and CPA-tumor by using the three-test battery.

Auditory Threshold↗

PubMed1993

Quantitative evaluation of the function of looking at visual target in optokinetic nystagmus.

A new method is presented to qualitatively evaluate the function of OKN which certainly looks at a visual target. Optokinetic stimulation was given to a test subject by projecting stripes with a 5 degrees visual angle width at 30 degrees intervals, which was accelerated by 1 degree/s2 up to 100 degrees/s. The correlation between slow phase and fast phase was computed with our program. Two correlations were mixed in a normal response, one indicated low correlation and the other high correlation. As normal subjects look at wide interval visual targets one by one regardless of the target velocity, low correlation type OKN beats are considered to be those which certainly look at the visual target. In order to quantitatively analyze this type of OKN, approximate regression lines of the low correlation type, [y = ax + b (x: slow phase velocity, y: fast phase amplitude or velocity)], were computed by the minimum square method. In normal subjects, value a indicates low and value b high velocity and their normal limits are determined. The results of cases with central disequilibrium indicate that this analysis provides information of pathological OKN different from that of such conventional parameters as slow phase velocity and number of nystagmus beats.

Dominance, Cerebral↗

PubMed1993

Effect of transdermally administered scopolamine on the vestibular system in humans.

In order to elucidate the effect of scopolamine on the vestibular system in humans, various experimentally-induced forms of nystagmus, i.e. caloric nystagmus, rotational nystagmus, optokinetic nystagmus, visual-vestibular interaction and optokinetic after nystagmus, were evaluated before and after the administration of two pieces of Scopoderm-TTS or placebo patches retro-auricularly. Scopolamine reduced the responses of both the caloric and optokinetic after nystagmus compared with the placebo. The possible action site of this drug is discussed.

Administration, Cutaneous↗