1 The lagenar macula is rectangular and the smallest of three maculae. 2 Many holes were observed in the otoconial membrane of the saccule. The hair bundles of the sensory cells penetrate these holes and occupy half of the hole space. 3 The otoconial membrane of the saccule was thinner than those of the utricle and the lagena. 4 Otoconia of the lagena were smaller than those of the saccule and the utricle. 5 In the striolae of the utricle and lagena, the density of the sensory cells was low compared to the other portion. 6 In the sacule, there was a linear portion which divides sensory cells into two groups. These group cells have sensory cilia which are arranged in such manner that they are facing each other. This line is suggestive of a striola. 7 Sensory cells with long stereocilia were often seen in the striola region. 8 The hair bundles were classified into three types in the utricle, two types in the saccule and the lagena.
The endolymphatic duct and endolymphatic sac of a guinea pig have been observed by a transmission microscope, and the following results have been obtained. (1) Not only the epithelium in the intermediate portion of the endolymphatic sac but also the epitheliums in other portions of the endolymphatic sac and those of the endolymphatic duct can be largely classified into two kinds of cells, namely, light cells and dark aells. (2) The capillary in the subepithelial layer of the endolymphatic sac has a fenestra and seems to be highly active. (3) Plasma cells exist in various parts of the subepithelial layer of the endolymphatic sac and a large number of macrophages is suspended in the cavity of the endolymphatic sac. That organ is in studying the immuno-function of the inner ear.
The action potential was recorded from an isolated frog utricle using a suction electrode. The utricle was stimulated by iron sand which was placed homogeneously on the macula. A magnetic force was employed to allow iron sand to mildly depress the macula. Integration of the action potential resulted in a phasic component just as observed in the isolated semicircular canal potential (Harada et al., 1969). The amplitude of the utricular phasic component was linear to the logarithm of the stimulus intensity. A similar relationship was observed between the semicircular canal action potential and the stimulus (Harada and Hirata, 1979). A phasic on-response was invariably accompanied by an off-response. This suggests functional polarization of the utricle. It is already known that the macula is divided by a striola into two hair cell groups with different polarities. Since iron sand is homogeneously placed on the macula, all the sensory cilia bend in one direction at the onset of the stimulus and one of the two cell groups evokes an on-response. At termination of the stimulus, sensory cells with the opposite polarity are stimulated, thus producing an off-response.
A study comparing the efficacy of an anti-motion sickness drug, Scopolamine, when administered in combination with an antihistaminic drug is presented. The possibility of classifying the subjects into two groups i. e. with vulnerability to or tolerance for motion sickness is also discussed. The subjects in this study were young students who had a normal vestibular function. Three groups of 10 subjects each were used and the following drugs were evaluated. 1. Dimenhydrinate, 50 mg. 2. Diphenhydramine salicylate, 40mg. 3. Scopolamine hydrobromide, 0.1mg and dimenhydrinate, 50mg. Each group received the acceleration and deceleration rotation testy and the sum of the values of the theoretical threshold (expressed by the angular deviation of the cupulaendolymph system) for the clockwise and counterclockwise rotation is evaluated after drug administration. The following items were pointed out in this study. 1. When a combination of dimenhydrinate and scopolamine was used, a large increase in effectiveness in preventing motion sickness was suggested. 2. Subjects vulnerable to motion sickness were differentiated from the normal subjects with their lower values than theoretical threshold value of 1.44°. This vulnerable group is more susceptible to the antimotion sickness drugs in the above mentioned combination than the other tolerant group.
Observing the course of nystagmus in dizzy patients is necessary to obtain the diagnostic characteristics of certain diseases and most dizzy patients can record this themselves using the Heart Corder. More-over, it is necessary to make repeated observations of dystagmus in medicated patients to evaluate the effect of the medication. Some of the patients provided these data themselves which they had recorded using the Heart Corder and particularly interesting data were obtained from a 30-year-old woman suffer-ing from a left acoustic neurinoma. these data indicated that nystagmus, caused by acoustic neurinoma, was occasionally suppressed by certain medications. In 21 other cases of nystagmus the data obtained had been recorded by the patients themselves using the Heart Corder. Because these data have been recorded on tape, they may be easily transmitted by phone, whereupon a high-cut-filter (5 Hz) attached to the "rerecoder" will allow a sufficient amplitude without the interfe-rence of static noise.
A clincal study was carried out on 105 vertiginous patients who had reduced unila to ral caloric responses and no cochlear symptoms. In 450 of the patients who complained of dizziness and showed reduced unilateral caloric response, ver-tigo or dizziness disappeared 3 months after the treatment. However, 5 of the 105 had reccurrent vertiginous attacks and one patient developed Ménière's disease. Nine patients who showed CMI type III or IV (Cornell Medical Index) still complained of dizziness after caloric responses improved.
Velocity patterns during saccadic eye movements were examined with 20 random jump.manners (different amplitudes of 8°, 16°, 24°, 32°, 40°. and 48° and different lighting times of 1sec, 2sec and 3sec and analyzed by means of a mini-computer (PDP 11/ 40). In normal subjects, the time course of ocular movements showed a convex curve pattern, which resembled the result obtained by Hyde (1959). Thirty-two patients were then examined. Patients with multiple degenerations, multiple infarctions, and gaze nystagmus showed irregular velocity patterns. Patients with Marie's ataxia showed somewhat irregular velocity patterns in deceleration perhaps owing to dysmetria. Patients with congenital nystagmus had slow increase rates of velocity when the direction of nystagmus was opposite to that of the saccadic eye movement.
The ultimate purpose of this study is to find a useful method for the differential diagnosis of central nervous system lesions. Patients complaining of vertigious symptoms were evaluated using the three popularly adopted neuro-otological methods, i. e., the caloric test, horizontal and vertical eye-tracking tests. We had discussed in another paper the use of the former two tests, and in this paper we studied how the vertical eye-tracking test was applied for diagnosis. At first the anatomical and physiological data of cats and monkeys with respect to the vertical and torsional eye movements were studied. The most basic of the vertical eye movements is that the gaze disturbance of the vertical plane is not caused by destruction in the specific area, theso-called "center". Most important is that bilateral brain tracts are activated simultaneously for the vertical eye movements. After this, the flow of impulses for the vertical and torsional vestibulo-ocular-reflex (VOR) were illustrated with reference to the basic data. Illustrations were made of the spike flows which induced by the electric stimulations of unilateral anterior canal nerve, posterior canal nerve, utricular nerve and vestibular nerve, and by the bilateral simultaneous caloric stimulation. Lastly, three cases were presented in detail, and the final diagnosis was made by studying the common region shared by the above tests.
Superior oblique myokymia is an intermittent uniocular microtremor caused by uncontrolled contractions of the superior oblique muscle, termed by Hoyt and Keane. As all the previously reported cases were healthy individuals, its lesion and mechanism have not been clarified. In this report, I introduced a patient with a cerebellar tumor who presented with superior oblique myokymia. A 41-year-old woman was admitted to the Nihon University Hospital with complaints of headache, dizziness and diplopia. A right cerebellar cyst was observed on computerized tomography and partial resection of this tumor was performed. Two months after this operation, she complained of oscillopsia and torsional diplopia. At that time, rapid, smallamplitude, intorted movements, that is superior oblique myokymia, were noted only in the right eye. This abnormal eye movement disappeared in one week. Thereafter, left cerebellar signs became apparent and visual suppression of nystagmus was reduced on both sides. Therefore, it was suspected that the tumor had already extended to the left cerebellum. From this clinical course and the experimental data of Ito, it was suggested that when the left flocculus was stimulated, the left superior vestibular nucleus was inhibited. Disinhibition of the right superior oblique muscle and disfacilitation of the right inferior oblique muscle resulted and the intorted movement appeared in the right eye. From these results, it seemed that the lesion responsible for superior oblique myokymia was the contralateral flocculus and this characteristic eye movement was produced when this region was stimulated temporarily.
Arm-deviation induced by rotatostimulation was studied by arm-kinetography, which was reported by this author in Equilibrium Research, vol, 41 (1), 1982. From the testing results of 36 patients with vestibular disorders, pathological patterns were classified into the following six types: 1) A hyporeaction type was observed in cases of bilateral peripheral vestibular disorders. 2) A hyperreaction tipe was observed in cases of brainstem lesions, 3) A directional preponderance type was observed in cases of unilateral peripheral vestibular disorders. 4) A plateau formation type was observed in cases of spino-cerebellar degeneration. 5) A slow reaction type was observed in cases of post-traumatic brainstem lesions. 6) A dysmetria and ataxia type was observed in cases of cerebellar disturbance.
The thalamic syndrome (Dejerine-Roussy Syndrome) resulting from the thalamic disorder is now understood as a syndrome characterized by hemiplegia, disturbance of sensation, hemiataxia, thalamic pain and choreoathetoid movement. Symptoms and signs resembling this syndrome, i. e. pseudo-thalamic syndrome, were reported in conjunction with some parietal lobe lesions. A case of pseudo-thalamic syndrome resulting from pontine hemorrhage is reported with a clinico-anatomical correlation study. The patient, a 56-year-old man, had suddenly developed right-hand numbness. Neurological examination on admission revealed Bruns-like nystagmus, slight disturbance of speech, right-sided hemiplegia, superficial and deep sensory deficiency and ataxia. A computed tomography taken 3 days after the beginning of the episode showed contrast enhancement around the bilateral pontine tegmentum (left dominant), but no abnormalities in the thalamus or the parietal lobe region. We discussed the topographical lesion of the symptoms and signs of the pseudo-thalamic syndrome seen in pontine tegmenturn hemorrhage. We concluded that a pseudo-thalamic syndrome resulting from pontine lesions will be characterized by the presence of nystagmus.
A patient with ventricular hemorrhage into the fourth ventricle who manifested divergence nystagmus was reported. Surgical removal of the hematoma resulted in disappearance of the divergence nystagmus immediately after the operation. There have been few reports dealing with divergence nystagmus, and there has been no general agreement so far concerning its mechanism. We reviewed the literature and discussed the mechanism.
The role of the cerebellar flocculus on optokinetic nystagmus was reviewed. The cerebellar flocculus, being a part of the pursuit system in primates, contributes to the optokinetic system in producing an initial rapid increase in slow-phase velocity of optokinetic nystagmus. It compensates for the optokinetic system at high velocities of optokinetic slow-phase eye movements.
The recent advances in Meniere's disease research in the United States have been on all fronts, in understanding the pathology and pathologic physiology of Meniere's disease, the natural history of the disease, and in testing to verify the presence of endolymphatic hydrops, and in various forms of medical and surgical treatment. The electrocochleography, using the acetazolamide hyaration and glycerol dehydration tests, has added greatly to our understanding of Meniere's disease. The continued investigation of the vestibular aqueduct by hypocycloidal polytome and in the future with CAT scanning has increased our understanding of the cause of idiopathic endolymphatic hydrops and the likelihood of benefit from operations on the endolymphatic sac. The observation that ears with Meniere's disease have an angle of less than 70 degrees between the vestibular aqueduct and the posterior semicircular canal as compared to normals in which the angle is always greater than 70 degrees will be, if true, very helpful in quantifying the diagnosis of Meniere's disease. Continued interest in early operations on the endolymphatic sac should increase information about the value of this procedure. Clearly the treatment for Meniere's disease must recognize it for what it is, an insidious, usually progressive but extremily variable disorder of the inner ear. Without question the funda-mental cause is developmental, a small, misplaced Early in life the regulation of fluid balance in the sac. inner ear begins to be compromised but there is enough excess capacity in the system to compensate for the small inadequate sac. The Dynamic Flow Theory of Lundquist (Figure 26) best explains the probable sites of production and absorption of endolymph and the roles of the stria vascularis and the endolymphatic sac. At this point there may be an insult to the system, to the stria vascularis and/or the endolymphatic sac, to disturb this already compromised equilibrium. This insult may be chemical, as by overloading the body with sodium and hence we believe the real but as yet unproven value of salt restriction and potassium-sparing diuretics in the management, not cure, of Meniere's disease in the early, still fluctuating stage. This insult may be metabolic, from disorders of glucose and/or lipid metabo lism, hence the very real obvious value of correcting these disorders when present. This insult may be autoim mune, the exact trigger for which remains to be found, hence the large number of patients with Meniere's disease with positive tests of autoimmunity to purified collagen likely to be present in the inner ear and the remarkable response in some patients to large doses of steroids. The insult may be other as yet unproven wtimuli shich remain to be found. Once this insult to the system takes place, the already compromised equilibrium is overwhelmed, the disease enters the uncompensated phase and hydrops of the cochlear and/or vestibular labyrinth occurs, and corresponding signs and symptoms appear. Most patients are first seen by the doctor after the system is compromised and treatment must be consistent with the situation which exists. That is why we have attempted to make the diagnosis early, before the system is compromised, and do the subarachnoid endolymphatic shunt early, which seems to us the most reasonable thing to be considering all the circumstances existent at that time.