Normal subjects stood upright on a platform that moved horizontally, and were examined their visual, vestibular and proprioceptive reflexes.
Postural responses induced by horizontal sinusoidal swaying of the platform were measured in terms of movements of the head, shoulders, hips and knees and the integrated EMG of the gastrocnemius muscle (GM). The transfer function was calculated with platform movements as input and postural response as output. The results were displayed as Bode plots, and the patterns of postural response were deduced from these Bode plots.
1. A basic pattern of postural response was clearly demonstrated. In subjects with their eyes open or closed, at platform movements of 0.3Hz, the various parts of the body moved together with the platform movement. When the platform movement exceeded 1Hz, the lower half of the body and the upper half of the body swayed with the hips as fulcrum. When the eyes were closed, at 0.3 and 1Hz the amplitude of movement of each part of the body was larger than when the eyes were open.
2. The role of visual, vestibular and proprioceptive reflexes in this type of postural response was clear.
1) Visual input reduced the amplitude of body sway at frequencies less than 1Hz.
2) The labyrinthine reflex was presumed to have participated in the delay in phase of head to platform movement at frequencies of 1 to 3Hz.
3) At a platform movement of 3Hz, regardless of whether the eyes were open or closed, GM activity appeared when the muscle was extended, presumably induced by the stretch reflex.

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In human subjects optokinetic spinal reflexes, nystagmus and vertigo are induced by optokinetic stimulation. Responses induced by the rotation of an Ohm-type cylinder (2m in diameter and 2m in height) were studied in human adults.
Experiment A. The cylinder was rotated with a constant angular acceleration of 2°/sec² for 90 seconds. The subject was instructed to step in place at the center of the cylinder while looking at its moving stripes. When the cylinder speed was slow, the angle of stepping deviation was small, and vertigo was not present. When the stimulus speed was fast, the slow phase of eye speed was slower than the movement of the stripes, the subject complained of vertigo and the angle of stepping deviation increased.
Experiment B. The cylinder was rotated with a constant angular acceleration of 1°/sec² or 4°/sec². Changes in the angular acceleration of optokinetic stimulation showed no differences in the patterns of responses.
Experiment C. The subject was instructed to step in place at the center of the cylinder carefully watching an otogoniometer. Optokinetic nystagmus was suppressed. When the cylinder velocity was slow, the angle of stepping deviation was larger with than without the otogoniometer.
Experiment D. Optokinetic stimulation was provided by double cylinders. The outer cylinder was an Ohm-type cylinder, and the inner cylinder had 12 visual targets. The subject was instructed to follow the targets of the inner cylinder. Stepping deviation was induced by the outer cylinder. There was little or no vertigo.
Experiment E. The changes of responses induced by repeated optokinetic stimulation (optokinetic training) were studied. The subject was trained daily for 3 weeks. After a 2 week interval the training was repeated for 2 more weeks. Optokinetic training resulted in a decrease of stepping deviation, an increase of optokinetic nystagmus and tolerance to optokinetic vertigo. Thus, training results in an increased adaptability to optokinetic stimulation.

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Body sway while standing was examined in 24 patients with spino-cerebellar degeneration (SCD) and 12 patients with cerebellar tumor.
The subject was instructed to stand with his feet together in the center of the statograph. His head was then connected to a cephalograph fixed to the ceiling. The sway of the head and the center of gravity of the body were recorded simultaneously with two X-Y recorders and a 4-channel magnetic tape recorder for 60 seconds with eyes open and 60 seconds with eyes closed. On the basis of the X-Y recordings, measurement of the area of sway, classification of sway types and calculation of the Romberg quotient were performed. The tape recording results were used to measure the length of the sway and the number of waves and for correlation analysis and power spectral density analysis with a PDP-12 computer.
(1) Thirteen patients with the cerebellar type of SCD, including LCCA, showed a diffuse sway of large amplitude with an irregular periodicity of about 0.1-0.3Hz. Romberg's sign was negative. The sway of the head was greater than that of the center of gravity of the body. The number of waves was within normal limits.
(2) In 11 patients with SCD with brain-stem and spinal cord symptoms in addition to cerebellar symptoms, including OPCA and Menzel type atrophy, the center of gravity showed a forward and backward sway with an irregular periodicity of about 0.1-0.2Hz with the eyes open, and 0.4-0.6Hz with the eyes closed. The number of waves was about twice normal. The length of the sway was markedly increased, while the area of the sway was only slightly increased in the statograms.
(3) In 7 patients with cerebellar hemisphere tumors, the sway of the head and the center of gravity showed a large and diffuse sway with an irregular periodicity of about 0.2Hz. The length of the sway was increased, but the number of waves was less than normal. The center of the sway of these patients was displaced in various directions.
(4) In 5 cases of cerebellar vermis tumor, the head showed a large and diffuse sway with a periodicity of about 0.1-0.3Hz, and the center of gravity showed a centripetal sway with an irregular periodicity of about 0.1-0.3Hz. The number of waves of both the head and center of gravity sway was normal. The area and length of the sway in patients with vermis tumor were much larger and longer than those in patients with hemisphere tumor.

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Meniere's disease is characterized by recurrent attacks of vertigo. It is difficult to predict the period and severity of the next vertiginous attack or whether the hearing disturbance will increase or not.
Patients with Meniere's disease were questioned about the course of their vertiginous attacks and hearing disturbance, and their responses were analysed.
Eighty cases of Meniere's disease with a duration of one year or more were included in this study.
The diagnosis was based on the criteria of diagnosis of Meniere's disease by Tokita et al. (1975, 1980).
Six different patterns of vertigo were noted:
Type 1: In 6 cases, definite severe attacks at long intervals changed to mild attacks at short intervals.
Type 2: In 16 cases, attacks occurred seasonelly once or twice every year.
Type 3: In 12 cases, the severity of attacks gradually decreased.
Type 4: In 18 cases, the attacks recurred frequently from the time of onset.
Type 5: In 7 cases, there was a single definite attack followed by bursts of attacks at irregular intervals.
Type 6: In 11 cases, isolated vertiginous attacks recurred irregularly at long intervals.
Hearing disturbances were also classified into 6 types.
In some cases, Meniere's disease was preceded by TIA, OD, Vestibular Meniere's disease, sudden deafness, or Lermoyez's syndrome.
These findings helped to evaluate the effect of medical treatment and to estimate the prognosis of Meniere's disease.

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Three steps were used to investigate possible predisposing conditions in patients complaining of dizziness of unknown etiology: (1) a detailed questionnaire, (2) routine physical and laboratory examinations and (3) loading equilibrium tests.
The first step provided information on the present illness and past history of systemic diseases. In the second step, we examined the circulatory system, autonomic nervous system, metabolic system, electrolytes, blood, liver function, neck condition and also evaluated the Cornell Medical Index. In the third step, a stabilometer was used to examine the patients while standing, during pressure on the carotid sinus, pressure on the eyeballs, neck torsion, neck retroflexion and vibration of the neck muscles. The equilibrium examinations provided the most important clues to etiologic factors.
Sixty patients (Group A) complained of dizziness due to disorders of the central nervous system and 206 patients (Group B) complained of dizziness of unknown etiology. Controls were 105 healthy adults. The chi-square test was used to analyze the difference between each group of patients and the controls.
The incidence of the following disorders was significantly higher in the patients than in the controls: in Group A step 1 showed circulatory disorders (61%), cervical diseases (18%), neurological disorders (27%) and digestive disorders (64%) and in Group B circulatory disorders (66%), autonomic disturbance (65%), blood disorders (23%), cervical diseases (31%), neurological disorders (35%) and digestive disorders (61%). In step 2, circulatory disturbance (63%), metabolic disorders (72%) and disorders in CMI (60%) were found in Group A, and circulatory disturbance (85%) and disorders in CMI (48%) in Group B. In step 3, equilibrium was disturbed by the orthostatic test in 25%, by pressure on the carotid sinus in 63%, and by neck torsion in 50% in Group A; by the orthostatic test in 24%, by pressure on the eyeballs in 34%, by pressure on the carotid sinus in 43%, and by vibration of the neck muscles in 39% in Group B.
These results indicate that the patients had a variety of systemic abnormalities. A majority had a combination of abnormalities. Therefore, predisposing conditions should be investigated by the 3 steps mentioned above. Loading equilibrium examinations were most effective in distinguishing conditions, causes of dizziness and from unrelated. These results may serve as a useful guide to the diagnosis and treatment of dizziness of unknown etiology.

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Peculiarities of optokinetic nystagmus (OKN) in patients with cerebellar disturbances were studied by a method which examines the relationship between optokinetic nystagmus and target movement.
An Ohm-type rotating cylinder was rotated electrically with an angular acceleration of 2°/sec² for 90sec. OKN, induced by optokinetic stimulation, and signals. of stripes rotating in front of the subject were sampled at 100Hz for 90sec by a PDP-12 computer through an analog-to-digital converter. The stripe movements were calculated from stripe signals using Lagrange's square interpolation formula. The nystagmus waves and stripe movement were superimposed on a cathode ray tube.
The test was given to 7 patients with late cerebellar cortical atrophy (LCCA), 1 with Holmes type atrophy, 11 with olivo-ponto-cerebellar atrophy (OPCA), 1 with Menzel's atrophy, 6 with cerebellar hemisphere tumors and 8 with vermis tumors.
OKN of patients with LCCA showed a square wave jerk, saccadic pursuit and delay of eye movements in stripe pursuit and ocular dysmetria in target catching. OKN of patients diagnosed as having OPCA showed a deficit of smooth pursuit and delay of eye movements in stripe pursuit and delayed initiation and reduced saccadic velocity in target catching. When the stripe speed was increased, pursuit of stripe movement became virtually impossible, and the number of nystagmus beats decreased markedly. Patients with cerebellar hemisphere tumors showed no abnormality of OKN. Those with vermis tumors showed abnormalities similar to those in patients with LCCA or OPCA.
The difference between OKN abnormalities in LCCA and OPCA is presumably due to the fact that in LCCA degeneration of Purkinje cells in the cerebellar vermis is predominant, whereas in OPCA there is also degeneration of the pontine nuclei.

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Inverted optokinetic nystagmus (OKN) was observed by a method of examining the relationship between optokinetic nystagmus and target movement.
An Ohm type rotating cylinder was used to examine horizontal OKN. Twelve vertical stripes were drawn at equal intervals on its inner surface. The cylinder was rotated with an angular acceleration of 2°/sec² for 90°sec. OKN, induced by the optokinetic stimulation, and signals indicating that stripes passed in front of the subjects, were simultaneously recorded by an electronystagmograph and a magnetic data recorder. Data on the tape were analyzed by a PDP-12 computer. The nystagmus wave and stripe movement were superimposed on a cathode ray tube. From the relationship between the two, the ocular ability to catch and follow the stripes was evaluated.
Inverted OKN was observed in 20 patients with congenital nystagmus.
In a representative examination, at a cylinder speed of 0-20°/sec, the eye followed the stripe movement with repeated saccadic movements of small amplitude. At a cylinder speed of 21° to 30°/sec, the moving stripe was followed by saccadic eye movements of large amplitude. When the cylinder speed surpassed 70°/sec, the amplitude and rhythm became uniform and developed into typical OKN. In this phase, the eye produced a saccadic eye movement in the direction of the stripe movement when the fovea registers a stripe.
These findings suggest that inverted OKN is due to stripe pursuit with saccadic eye movements.

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The dynamic characteristics of the visual-vestibular and cervical oculomotor system were studied by the transfer function in normal subjects and in patients with labyrinthine dysfunction.
1. The transfer function of the visual oculomotor system showed that the gain and phase were flat in a frequency range from 0.4 to 1.0Hz. Thus, the visual oculomotor system has a target movement fixation capability to a frequency level of 1Hz.
2. The transfer function of the vestibular oculomotor system showed that the gain increased linearly at a rate of 5 dB/decade when the frequency of head oscillation increased from 0.3 to 2.5Hz. This result indicates the importance of the vestibulo-ocular reflex in visual fixation during fast head oscillations.
3. The transfer function of visual-vestibular oculomotor coordination showed that the gain and phase were flat in a frequency range from 0.4 to 3.0 Hz. Thus, visual fixation during head movement to a frequency level of 3Hz is achieved by means of coordination of the visual-vestibular oculomotor systems.
4. The cervical oculomotor system does not act independently as a stimulus to induce manifest eye movement, but under conditions of coordinated action with the visualvestibular-cervical oculomotor systems, visual fixation is achieved to a frequency level of 4 Hz.
5. The transfer function of visual suppression of the vestibulo-ocular reflex showed that the gain increased linearly at a rate of 30dB/decade when the frequency of head oscillations increased from 0.3 to 3.0Hz. The visual suppression of the vestibuloocular reflex is fairly strong at low frequencies, compared with the dynamic characteristics of the vestibular oculomotor system.
6. Patients with bilateral loss of labyrinthine excitability exhibited disturbance of visual fixation when head movements exceeded 1Hz.
7. Patients with unilateral loss of labyrinthine excitability were capable of visual fixation when head movements exceeded 1Hz, but the frequency range was below normal.

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Fifty-two patients with chronic vertigo associated with underlying circulatory insufficiency were treated with 3-6mg of Dihydroergotamine daily for about 4 weeks and followed for changes in (1) subjective vertigo, (2) vestibular function, (3) signs of disorders of the inner ear and central nervous system, (4) predisposing conditions, and (5) associated symptoms. Each sign, symptom or abnormal test result was graded as mild, moderate or severe. The therapeutic results were rated on a 5-point scale: marked, moderate, or slight improvement, no change or aggravation in comparison to the pretreatment level.
(1) The improvement rate for subjective vertigo was 69%.
(2) For vestibular function, the improvement rate was 25% for voluntary nystagmus, 48% for the Romberg test, 56% for the writing test, a test of deviation reaction, and 52% for the stepping test.
(3) Those with disorders of the inner ear and central nervous system showed no improvement by audiometry, but in the test for nystagmus caused by labyrinthine stimulation, the improvement rate was 38%.
(4) In regard to predisposing conditions, the improvement rate for OD symptoms was 73% and that for Schellong's test was 55%.
(5) Relief of associated symptoms was high for nausea and vomiting (70%) and headache (50%).

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