To clarify the features of labyrinthine equilibrium disturbances, body sway in the upright standing posture was studied by a time series analysis with a 5-dimensional feedback model. Sways of the head, shoulder and hip and activities of the nuchal and rural muscles during upright standing were recorded polygraphically and stored in the memory of a PDP-11 computer. Data processing with a 5-dimensional feedback model was performed in a specially designed program. The results were displayed on a cathode ray tube and teletype as determinant of noise correlation matrix, power spectrum, correlogram, transfer function (Bode plot) and relative power contribution. 1. The determinant of noise correlation matrix on upright standing with eyes closed was 0.49 using linear movement of the head agdinst 0.73 using angular movement of the head. The vestibulo-spinal system has a good feedback when angular movement is used as head sway. 2. Power spectrum and correlogram of head movement indicated that head movement was a slow irregular sway with marked decrease of power in a frequency exceeding 1 Hz. The results indicate that the vestibulo-spinal system controls body sway of low frequency. 3. The transfer function calculated with head movements as input and the nuchal muscle activities as output indicated an increase of the gain in the frequency range from 0.02 to 1 Hz. The gain obtained from the sural muscle activities as output was flat. These features of the Bode plots suggest the dynamic characteristics of the vestibulo-spinal reflex. However, more than half of the subjects showed different features in their Bode plots. 4. In the relative power contribution, the proportion induced by the head movement in the autopower spectra of the nuchal and sural muscle was from 1% to 14% in the frequency range from 0.2 to 1 Hz. The vestibulo-spinal system regulates body sways of low frequency during upright standing. However, the proportion of the contribution of the vestibulospinal system is low in the whole control of standing posture.
Isolated posterior semicircular canals of bull frogs were used. The cupula was removed from the crista, and the sensory cilia on the crista were depressed towards the canal side by a glass micropipette. Seven different points from one ampullary wall side to the other were selected for stimulation. Ampullary nerve action potentials induced by depression were recorded and were converted into spike density histograms. Response decremental time constants were measured on the histograms. The longest time constant was measured at the 2 lateral points of stimulation which progressively shortened towards the central point. The shortest one was obtained at the central point of stimulation. These results indicate that the origin of the response adaptation is possibly sensorineural.
Electronystagmogram recordings in OKP test should show a symmetric pattern. However, asymmetric patterns are not rare This study was done to confirm this and to clarify the characteristics of the asymmetric pattern related to age in both normal subjects and patients. The mean eye-velocity of the slow phase of nystagmus and the number of beat every 5 seconds were compared in the acceleration and deceleration phase. Each normal group included 10 to 12 cases, seven groups from the first to the seventh decade were tested. Patients in the third decade, whose OKN was markedly suppressed, were also tested. 1. The eye-speed of the slow phase of nystagmus in the deceleration phase was slower than in acceleration at drum-speeds of 40 to 140°/sec in males and 20 to 100°/sec in females in the seventh decade. However, the eye-speed in the acceleration phase was slower than in deceleration at drum-speeds of 80 to 140°/sec in males and 80 to 120°/sec in females in the second decade. 2. The number of nystagmus beats was less in the deceleration phase than in acceleration at drumspeeds of 80 to 120°/sec in males and 60 to 100°/sec in females in the seventh decade. 3. In the patients, the eye-speed in the nystagmus slow phase in the deceleration phase was slower than in acceleration at drum-speeds of 80 to 140°/sec.
Neurotological examinations were performed on patients with unilateral cerebral vascular deficits, with special regard to oculomotor function. Materials and method: Twenty-six patients with hemiplegia due to vascular disturbances in the territory of the middle cerebral artery were examined and analysed neurotologically. Audiometry, equilibrium test, nystagmus test, oculomotor function tests (OKN, pursuit and saccadic eye movement), caloric test and visual suppression test were carried out. Eye movements were recorded electronystagmographically, and horizontal eye movements were correlated with the side of the lesion. Patients were classified as deep form and cortical form according to the location of the lesion, and also to acute and chronic groups according to the course of the disease. Results : Gaze nystagmus to the side of the lesion was observed in three patients with cortical lesions, in the acute group. Some kind of nystagmus (gaze, positional and positioning nystagmus) was seen in 16 patients. Optokinetic nystagmus towards the side opposite to the lesion was much more deranged in 22 patients. Saccadic eye movement was also disturbed towards the side opposite in 9 patients, 6 of whom had cortical lesion. Smooth pursuit, on the contrary, showed little difference between the two directions, and only 4 patients showed saccadic pursuit towards the side of the lesion. The quick phase of caloric nystagmus was not disturbed even in patients with disturbed voluntary saccade.
The labyrinthine status before and after episodes of Meniere's disease was investigated by the acceleration-deceleration test (±2, 4, 6, 8, 10°/sect2, 10") using Contraves' computerized rotary chair system. The difference in duration between nystagmus induced by acceleratory stimulation and nystagmus by deceleratory stimulation was used as an indicator to observe the clinical course of 10 patients with unilateral Meniere's disease. As a rule, ipsilateral labyrinthine preponderance appeared in the pre-episodic stage, and contralateral labyrinthine preponderance was observed in the postepisodic stage. If the interval until the next attack was long, contralateral labyrinthine preponderance disappeared or changed into the vestibular recruitment type. It was thought that ipsilateral labyrinthine preponderance was an indicator to predict the next attack, and the vestibular recruitment type showed a stabilized state of the labyrinth.
The area of sway, which is believed to be one of the most important parameters reflecting standing ability, be measured by planimeter. The Japanese Equilibrium Research Association recommends that. On the other hand, the product of the maximum widths in both X and Y directions is also used, since measurement by planimeter is difficult to use clinically. This paper aims to clarify the relationship between two methods. The area measured by plani meter and the product of the maximum widths in both X and Y directions are called A and B, respectively. Statokinesigrams of 500 patients aged 5 to 80 years with eyes open and eyes closed were analyzed and the correlation between A amd B was analyzed statisticaliv. 1 ) With regression analysis, the correlation coefficient of A associated with B was determined to be: r=0.953 in the group with eyes open, r=0.968 in the group with eyes closed. Relationships between A and B in both groups were statistically significant at the level of 0.001. 2) The data were fitted to the following regression equation: Y=0.443X-20.47 in the group with eyes open, Y=0.441X-5.689 in the group with eyes closed. (X=B, Y=A) The regression coefficients in both groups were significant (P<0.001). It is concluded that the area of a square, which encloses the figure of the sway, can be used as a substitute for the area measured by using a planimeter statistically. However, it is necessary to measure the area of the body sway by using a planimeter in some individuals directly, since the ratios of A to B showed values from 17.7 to 68.7 per cent.
When blood pressure and pulse rate are measured in Schellong's Test using a Continuous Blood Pressure Monitor, data must be displayed clearly so that their trends can he grasped easily with the lapse of time and in response to various loads. The display devise of UEDA's Monitor has been improved for this purpose in the following two points. 1. Digital displays of measured time, systolic value, diastolic value and pulse rate are rearranged for easier observation. 2. Spaces between printed lines have been narrowed to show the blood pressure trends more clearly. The use of this monitor in Schellong's Test will facilitate both clinic judgement and explanation of the test results.
In patients with peripheral vestibular lesions, such as Meniere's disease, the vestibulo-autonomic reflex is frequently activated during attacks of vertigo. In patients with central autonomic nerve disorders, such as Shy-Drager's syndrome, on the contrary, dizziness or equilibrium disturbances may be caused. Therefore measurement of the autonomic nervous system is indispensable in equilibrium examinations. We have developed a new method of measuring RR intervals using a microcomputer. This system of analysis makes it possible to measure the static and dynamic functions of the autonomic nervous system.
A survey was made of patients over 65 years of age with vertigo or dizziness examined in the Neuro-Otological Clinic of Nagasaki University Hospital from 1969 to 1983. 1)The number of elderly patients increased significantly, especially those 70 to 74 years ofage. 2)The varieties of diseases increased by more than ten since 1975, but congenital nystagmus, epileptic vertigo, pressure trauma and autonomic disturbance did not occur in this age group. 3)Cerebro-vascular disorders and/or dizziness due to unknown etiology or due to inner ear disorders of unknown cause were seen more frequently. 4)BPPV increased characteristically in this group.
A total of 2028 cases of dizziness examined during the past three years was divided into two groups ; those aged under 60 years (non-elderly people) and those aged over 60 years (elderly people). A comparison was made of the incidence of dizziness in each group to study the characteristics of dizziness in elderly people. In both sexes, the incidence of orthostatic dysregulation was significantly lower and that of cervical vertigo and central dizziness was significantly higher in the elderly than in the non-elderly group. There was no singnificant difference between the two as to other types of dizziness. The incidence of dizziness in elderly people was in the order of orthostatic dysregulation> cervical vertigo> central dizziness. There was no difference between the sexes as to cervical vertigo. The increase in the incidence of cervical vertigo was considered to be due to aging. The incidence of central dizziness showed a difference between the sexes (men> women) in addition to the increase due to aging, which led us to conclude that central dizziness is affected by life style and customs. The incidence of orthostatic dysregulation was high in elderly patients treated with anti-hypertention drugs. The incidence of psychogenic dizziness was significantly high in elderly women, which led us to surmise that the home environment is related to the development of psychogenic dizziness.
In the observation and therapy of patients with herpes zoster oticus, who have disturbances of several cranial nerves, only conspicuous symptoms such as facial nerve palsy and auricular vesicles are usually regarded as important. Sometimes, however, continuous observation of these patients shows vestibular dysfunction, even if they do not complain of vertigo or disequilibrium. In patients suffering from this syndrome, damage of the vestibular nerve sometimes remains after good recovery of other affected cranial nerves. While vestibular dysfunction persists these patients must move carefully, especially in the dark. An 18-year-old female had right tinnitus, right sensorineural hearing loss, right facial palsy, disequili-brium and vesicles in the right pinna and external auditory meatus. Positional nystagmus was tested many times with electronystagmography until it dis-appeared. For one year vestibular function was examined after recoverv of the other cranial nerves.
A 67-year-old woman developed clinic al findings consistent with herpes zoster of the left ear, localized encephalitis and meningitis. These signs included herpes of the left external ear and soft palate, VIIth and VIIIth nerve disfunction, ataxia and electro-nys-tagmographic (ENG) abnormalities ; defective opto-kinetic nystagmus and saccadic pursuit towards the right. Treatment with adenin arabinoside (Ara-A) resulted in rapid improvement. The importance of CSF examination including cell counts and CSF-IgG index, ENG and EEG was emphasized.
Two cases of opsoclonus-polymyoclonus syndrome are presented. A 62-year-old housewife with a history of hypertension suddenly developed headache, nausea, vomiting, numbness and motor disturbance of the extremities, paresthesia, vertigo, tinnitus and deafness. Neurological examination showed difficulty and unsteadiness in gait, slurred speech, pseudobulbar palsy, left motor weakness and dysmetria of extremities with sensory deficit of the left arm. Computer tomography, electroencephalogram and virus titers revealed no abnormal findings, but left vertebral-angiography showed an abnormal double shadow of the vertebral artery. Audiometry showed low tone sensory neuralhe aringl oss on the left side. There was complete gaze directional nystagmus, butabout one monthafter admission horizontal rapid irregular eye movement (opsoclonus) with palatal myoclonic jerking was observed when the eyes were open. The abnormalities in this case seen to be due to cerebellum and brain stem lesions secondary to vertebral artery damage. A 34-year-old female had an upper respiratory infection anorexia, nausea and general fatigability one month prior to admission. Her gait gradually became unsteady and staggering. Rapid irregular eye movement (opsoclonus) synchronized with jerky movement of the larynx gradually increased in severity. She showed moderate cerebellar signs but no sensory disturbance. In the treatment of this case steroid therapy proved to be quite effective. The etiology of the opsoclonus observed in these two cases appears to differ neuropathologically.
A 55-year-old man had left hearing loss, left facial hypesthesia, left facial nerve palsy and loss of taste after the sudden onset of double vision and severe rotatory vertigo accompanied by nausea and vomiting. A neurosurgeon made the diagnosis of possible infarction of the anterior inferior cerebellar artery on the basis of VAG and CT test results. Vestibular function tests at our otoneurological clinic revealed a severe righting-reflex impairment, gaze nystagmus, horizontal nystagmus to the right and down-beat nystagmus. The caloric test including ice water irrigation revealed no response on the left. The audiogram revealed total deafness of the left ear. ECoG revealed normal action potentials, but ABR revealed curiously only the first wave on the left ear. We suspected that the lesion was in the vestibular and cochlear nuclei, but that the inner ear remained intact. A month after his first attack this patient complained of dysphagia. The neurological examination revealed curtain phenomenon, weakness of the gag reflex and deviation of the tongue to the left. The above otoneurological findings suggested cerebellopontine angle tumor and surgery was performed. Facial nerve neurinoma of the cerebellopontine angle was confirmed. The circular disturbance of the anterior inferior cerebellar artery and its branches to these involved nuclei were probably due to compression.