In order to determine whether middle ear pressure changes cause disequilibrium or not, the influence of middle ear pressure on vestibular nerve activity was investigated in anesthetized cats. Vestibular nerve activity was recorded intraaxonally, and positive or negative pressure was applied to the middle ear cavity through a tympanic membrane perforation. The firings of vestibular nerve fibers, especially the regular type which responded to horizontal semicircular canal stimulation, were increased with positive pressure and decreased with negative pressure. Most vestibular nerves which responded to anterior or posterior semicircular canal stimulation were not influenced by middle ear pressure changes. These results indicate that the influences of middle ear pressure transmitted to the vestibular endorgans and then to the vestibular nerve probably cause disequilibrium.
Length (L) and surface (S) are indices which are applied to the auxiliary test in equilibrium examinations. Both indices are considered to increase proportionally; longer the length, larger the surface. However, these do not vary in the same way. In some cases, L is normal or only slightly increased, whereas S is greatly increased. In others, there is only a slight increase in S with a great increase in L. We called this finding dissociation of L and S in stabilometry, the former the surface dominant type and the latter the length dominant type. In present study, we attempted to correlate the dissociation of L and S with clinical manifestations. 1. In patients with dizziness or vertigo, S tend to be increased, while L is only slightly changed. In other words, the surface reflects dizziness or vertigo. 2. Stabilometry shows four patterns in patients with vertigo : increased L and S, increased S and limited L, increased L and limited S, and normal L and S in that order. 3. We supposed that patients with the length dominant type of dissociation take frequent small steps when standing still.
This paper analyzes motion sickness data obtained from questionnaires in one kindergarten, four primary schools, and one middle school; a total of 2484 pupils. These data were studied by Hayashi's quantification method II. which includes 13 items : age, sex, vertigo, orthostatic dysregulation, getting out of bed, sports, running, hearing loss, poor posture, headache, gasping, pallor, appetite. Motion sickness was the outside criterion. The quantification analysis indicated the following : 1) The correlation ratio, which indicates the rate at which items explain the outside criterion, was 0.102. 2) The ranges of category weight, which are quantified to maximize the effect of grouping, were : age 1.175; appetite 0.888; sex 0.824; headache 0.671; and vertigo 0.563. 3) Partial correlation coefficients which indicate a single relation between the outside criterion and each item (excluding influence of other items), were : age 0.170; sex 0.134; appetite 0.092; headache 0.072; and orthostatic dysregulation 0.056. 4) From the cumulative distribution of sample scores (i.e. the sum of category weight in each case), motion sickness and non-motion sickness groups were discriminated at the rate of 65%.
In the United States, two “Guidelines for the diagnosis and evaluation of therapy in Meniere's disease” have been drawn up, one by the “Committee on Hearing and Equilibrium” of the AAOO (1972) and one by the AAO-HNS (1985). In Japan, two sets of criteria for evaluating Meniere's disease have been proposed, one by Uemura and one by Tokumasu independently of the former two criteria in the U.S. The former three guidelines, i.e. AAOO (1972), AAO-HNS (1985) and Uemura (1977), were compared in the same group of 67 patients, with unilateral Meniere's disease who had been treated with the same surgical procedure on the endolymphatic sac, i.e. Kitahara & Futaki's Saccus-Mastoid Shunt, from Sept. 1980 to Oct. 1984. The accuracy of the AAOO committee's evaluation of the “total results” by combining the changes achieved in reduction of improvement of vertigo and hearing seems to be less than that achieved by the AAO-HNS' and Uemura's criteria. The merits and demerits of each system are discussed, and Tokumasu's guidelines with the use of a microcomputer are described. On the basis of this comparison of four sets of criteria, the author proposes a revision of the guidelines for evaluating therapeutic procedures for Meniere's disease.
Eye movements were studied in 18 cases of cerebral lesions with dementia. Spontaneous nystagmus and gaze nystagmus were observed, and recorded by electronystagmography (ENG). Pursuit, optokinetic nystagmus, caloric nystagmus and visual suppression were examined. Disturbances of eye movements were seen in all cases of dementia. 1. Alzheimer type dementia There was no gaze or spontaneous nystagmus. Very mild vertical postitioning nystagmus was seen, as well as saccadic and ataxic pursuit. Optokinetic nystagmus and visual suppression were normal. 2. Multiple infarct dementia Disturbance of eye movements increased with the severing of the mental disorders. Pursuit eye movements, optokinetic nystagmus and visual suppression were greatly impaired in cases with lower parietal lobe lesions. There were no voluntary eye movements in the most severe cases. Eye movement disturbance was related to lower parietal lobe leisons.
A 41-year-old male had been suffering for 5 years from hearing loss and tinnitus on the right side accompanied by rotatory vertigo. Tomography revealed an enlarged intenrnal auditory meatus on the right side, with a vertical diameter of 12mm. The vertical diameter on the left side was 8mm. The tentative diagnosis was either Meniere's disease or acoustic neurinoma. Acoustic neurinoma was later ruled out by Air-CT cysternography, which showed normal air filling and no tumor in the right internal auditory meatus. We concluded that the enlarged internal auditory meatus of this patient was a normal variant. Clinicians must be aware of normal variations in the size of the internal auditory meatus in order to avoid misdiagnosis of acoustic neurinoma.
Three patients were found to have neurovasular cross-compression of the eighth cranial nerve. A 58 year old male and a 63 year old male had Meniere's symptoms : repeated attacks of unilateral tinnitus, fluctuating hearing loss, oscillopsia and dysequilibrium. A patient was normal caloric response and the other slightly reduced reaction. Their symtoms were not relieved by medical treatment (Isosorbide). The episodes became more frequent and occured in clusters with shorter periods of remission. One patient had attacks of vertigo which lasted 5 minutes. Angiography revealed a vascular anomaly causing obstruction in the AICA. At operation the AICA was seen compressing the eighth cranial nerve close to the porus acousticus in both patients. After surgery there was complete relief of symptoms after temporary hearing loss at low frequencies. A 44 year old male with benign paroxysmal positional vertigo was found to have an enlarged internal audiotory meatus, and pneumo-CT showed neurovascular cross-compression of the eighth cranial nerve by a loop of the AICA. The caloric response was normal and hearing loss was slight. These patients show that neurovascular cross-compression of the eighth craninal nerve can cause typical Meniere's symptoms or benign paroxysmal positional vertigo.
Two hundred and eight cases of benign paroxysmal positional vertigo (BPPV) were studied. The number of patients with BPPV has increased recently, especially those over 60 years of age. Head injury, hypertension, prolong bed rest and administration of streptomycin were significant causative factors. A neurotic tendency was more evident in BPPV patients than in normal subjects, but less than in those with Meniere's disease. The change in direction of positioning nystagmus between the sitting and the hanging position, which is supposed to indicate the pathology of the side, coincided with the side of semicircular canal palsy, critical position, hearing disturbance, etc. in 57%-74%. Vertigo disappeared in 40% of the case within the first week and in 40% more within the first month, but BPPV recurred in 30%. Physical exercise was very effective in the treatment of BPPV.
Cerebrovascular accidents in the territory of the anterior inferior cerebellar artery (AICA) are not uncommon. There is great variation in the origin and course of the AICA, which makes it difficult to diagnose morphological AICA syndrome. This suggests that to elucidate the clinical picture, neuro-logical and neuro-otological findings are more useful than morphological examinations, such as angiography. The clinical picture and findings in 6 cases are discussed. 1) The most prominent symptom was vertigo, associated with cochlear symptoms, followed by ipsilateral facial numbness. 2) Neuro-otological examination showed sensory hearing loss, gaze nystagmus, spontaneous nystagmus beating to the healthy side and disturbance of pursuit eye movements. 3) It is most important to pay special attention to the clinical findings in making the diagnosis.
We investigated the effect on the movements of the body's center of gravity (CG) of the distance between the eyes and the target in normal adults with a straingauge type stabilometer and a minicomputer. 1) The total length and area of CG movement increased as the distance between the eyes and the target lengthened. 2) The size of the visual target had no significant effect on body sway. 3) These results indicate that it is important to measure the distance between the eyes and the target in body sway tests.
Complete gaze directional nystagmus was observed transiently in a 59-year-old woman with left pontine infarction. She had had a sudden attack of headache, rotatory vertigo and double vision. Neurological examination showed incomplete left abducent nerve palsy, incomplete left facial nerve palsy, and sensory disturbance of the left arm and foot. The oto-neurological findings were complete gaze directional nystagmus and positional nystagmus towards the upper part of the ear. However, as her vertigo subsided, complete gaze directional nystagmus also subsided. We speculated that a small lesion of the midbrain, especially of the pons, could cause complete gaze directional nystagmus. We advocate the use of the Square Drawing Test (SDT) in patients with infarction of the midbrain.
Primary eye positional down-beat nystagmus (PPDN) due to bilateral inner ear anesthesia was analyzed. In our clinic, inner ear anesthesia is used as a therapeutic modality in a variety of patients undergoing treatment for vertigo and/or tinitus. The study population included only patients with one or more of the following complaints : vertigo, dizziness, tinnitus and hearing loss. In this study, 54 subjects were selected out of the initial group. Inner ear anesthesia was performed by introducing 4% lidocaine into the tympanic cavity via the external auditory meatus. Among the 54 cases, nystagmus appeared to be due to inner ear anesthesia in 47 cases. In 37 of the these cases, the observed nystagmus was PPDN. In the remaining 10 patients, horizontal, rotatory and oblique types of nystagmus were observed. The PPDN in the present study ranged from high frequency with low amplitude to low frequency with high amplitude. The latent period between the injection and the onset of the PPDN varied from 20 to 100 minutes. The duration of the PPDN ranged from less than one hour to 3 hours in the longest case, with an average duration of between one and 2 hours. Subjective reports of vertical oscillopsia were noted at the same time. These phenomena appear to be caused by the penetration of lidocaine into the inner ear through the round window, leading to anesthesia of the inner ear, which causes transient bilateral vestibular hypofunction of the inner ear, followed by gradual recovery of function and dissappearance of the effect.
We treated 42 patients with delayed endolymphatic hydrops (DEH) : 33 ipsilateral, 7 contralateral, and 2 bilateral. We conducted a clinical study of the 7 patients with contralateral DEH. Patients with contralateral DEH have a profound hearing loss in one ear, and eventually develop symptoms of endolymphatic hydrops in the opposite ear (only hearing ear) -fluctuating hearing loss with or without vertigo-, which is a very serious problem not only for the patient but also for otologist. The cause of the profound hearing loss in our 7 cases was head trauma, otitis media and mumps (1 case each), and juvenile unilateral deafness of unknown etiology in 4. The chief complaint was fluctuating and progressive hearing loss in the better hearing ear in 6, and rotatory vertigo caused by the normal hearing ear in 1. In the diagnosis of contralateral DEH, the clinical history is most important and the glycerol and furosemide tests are very useful. In the treatment of contralateral DEH diuretics and steroids have been employed. In those who failed to respond to conservative therapy, epidural shunt operation on the endolymphatic sac was performed in our clinic. The treatment was effective in many cases, but in some cases hearing loss progressed in spite of the intensive therapy. In the patients with advanced hearing loss already in the better hearing ear, it is very difficult to perform an operation because of the relatively high risk of making the hearing worse. We have tried γ-globulin therapy in some patients who showed a poor response to conventional therapy. This therapy sometimes yielded good results. The action of the γ-globulin on the inner ear and the endolymphatic sac is still unknown. But we believe that we should always strive to search for a more effective conservative therapy as well as trying to be more skillful in surgical management.
To clarify the influence of vestibular stimulation on upright standing, we analyze postural changes during caloric stimulation with cold water (20°C, 10°C, and 0°C). The power spectra of body sway were computed by a fast Fourier transform program. A relative decrease of frequency amplitude from 0.05-0.2Hz was observed in the X and 0.05-0.15Hz in the Y axis component. The presence of a frequency of about 0.3Hz was manifest in the X and of 0.2Hz in the Y axis component. When the stimulus was increased, the initial peak of the spectrum spread to the 0.3-0.5Hz band in the X and to the 0.2-0.5Hz band in the Y axis component. From these results, we concluded that postural changes during caloric stimulation have two components, postural deviation and body sway, and the transitional band is about 0.1-0.2Hz. We picked out a slow wave (less than 0.15Hz) from the linear stabilogram with a digital filter using a microcomputer. It seems that the neuronal mechanism of postural deviation and body sway are not the same.
An endolymphatic-mastoid shunt procedure was performed in 7 patients severely disabled with Meniere's disease. Their incapacitating vertigo had not been controlled by other treatments, e.g., various medications, acupuncture or stellate ganglion block. The vertigo was markedly relieved within 6 weeks after the surgery. It is apparent that this surgical treatment is still very effective.