There has been a tendency to investigate phenomena in vivo from the standpoint of the self-organizing system. According to this postulation, the order of the living body is established by the relationship between the parts and the whole with their mutual feed-back loops. The equilibrium system consists of two parts, peripheral equilibrium organs and their centers, and these two are closely connected by their feedback loops. Thus, the characteristics of the equilibrium system seem to be similar to those of the self-organizing system. In this paper, the following subjects are discussed from the standpoint of the self-organizing system. 1. Coordination and competition between the optic organ and the labyrinth with regard to the maintenance of body equilibrium. 2. Physiology of training of the optic organ and the labyrinth, and mutual transfer of effects of training of these two organs. 3. The characteristics of centripetal and centrifugal parts of the labyrinthine system. 4. The characteristics of exchange of information between the upper and the lower parts of the brain relevant to the maintenance of body equilibrium. The results of the above examinations suggest that the idea of the self-organizing system is an aid to the understanding of the characteristics of various phenomena with regard to the maintenance of body equilibrium.
Stabilometry, a test to examine body balance in subjects standing upright, was evaluated for its significance in the focal diagnosis of vertigo and equilibrium disturbances. 1. The pattern on X-Y recording of sway of the body center of gravity (statokinesigram) showed a right-left sway in unilateral labyrinthine disturbances, a forward-backward sway in bilateral labyrinthine disturbances and a diffuse sway in spino-cerebellar degeneration (cerebellar form). The type of the statokinesigram suggests the site of the lesion in patients with equilibrium disturbances. 2. The area of the statokinsigram corresponded with the severity of vertigo and equilibrium disturbances. Measurement of the area was useful in following the course of the disease and in evaluating the effects of medical treatment and of equilibrium training. 3. Determination of the locus length per unit area (L/A) was useful in evaluating the fine control of standing posture by spinal proprioceptive reflexes. 4. Measurement of deviations of the center of body sway was useful in evaluating the severity of unilateral labyrinthine disturbances. 5. The Romberg coefficient was useful in testing the visual control of standing posture and in detecting disorders of spinal afferents, such as the posterior funiculus and the spinocerebellar pathway, and of the labyrinth. For focal diagnosis in patients with equilibrium disturbances, it is important to evaluate the combined results of the above examinations.
Inner ear anesthesia was performed in 110 patients with Meniere's disease refractory to medication. The criteria for the evaluation of the therapeutic effect were AAOO (1972), AAO-HNS (1985), and Sakata's (1987) which have different evaluation periods. With AAOO, 7% of the patients were class A, 33% class B, 8% class C and 52% class D. AAOO requires an evaluation period ten times the average interval between attacks, so the periods of evaluation are long and there were 19% indeterminable cases. AAO-HNS is expressed by a numerical score, and 48% of the patients scored 0, 33% scored 1 to 40, 7% scored 41 to 80, 9% scored 81 to 120 and 3% scored>120. With Sakata's criteria, 52% of the patients had an excellent response, 34% a good response, 9% were unchanged and 3% were worse. The average evaluation period was 21.8±18.8 months (mean±SD) for the AAOO group, 24 months for the AAO-HNS and 9.5±3.3 months for the Sakata group. Only a 4% difference in the apparent rate of complete suppression of vertigo was observed between the Sakata group with an evaluation period of about 10 months and the AAO-HNS group with an evaluation period of 24 months. Thus an observation period of about 10 months yields results similar to that of one of 24 months. In addition to setting an evaluation period for determining the effect of treatment in Meniere's disease, seasonal variations of vertigo attacks should also be considered. We conclude that an observation period of one year is optimal for evaluating treatment in Meniere's disease. Inner ear anesthesia had an effectiveness rate of 81% in the treatment of vertigo according to AAO-HNS criteria, and one of 61% in the treatment of tinnitus. Inner ear anesthesia should be considered for patients with Meniere's disease as a conservative treatment before a decision is made to perform surgery.
In normal subjects, the furosemide test reveals a diminishing magnitude of the maximum velocity of the slow component of caloric nytagmus. This phenomenon is called response decline (habituation) because of repetitive caloric stimulations. There have been many reports on the response decline phenomenon, but we have found none on the tests with the same intervals of repetition of caloric stimulation as in the furosemide test. In this study we examined 27 normal subjects to determine whether or not the response decline phenomenon occures when caloric stimulation are repeated at the same intervals as in the furosemide test but without the administration of furosemide. In the case of the repetition of the caloric test without the administration of furosemide, the magnitude of the maximum velocity of the slow component of caloric nystagmus was not so diminished than that of the frosemide test in normal subject. Therefore, we conclude that there is some cause other than response decline phenomenon to explain the diminishing of the maximum velocity of the slow component of the furosemide test in normal subjects.
Quantitative analysis of saccadic eye movements by randomized visual stimulation in the horizontal plane was carried out in 131 normal subjects with Contraves' computerized oculomotor testing system. 1. In order to evaluate the influence of the saccade amplitude, we investigated the relationships between the saccade amplitude and the maximum velocity, duration, latency and gain. The saccade amplitude and maximum velocity had a nonlinear relationship, and the saccade amplitude and duration were found to be linearly correlated. 2. Investigation on the effect of increasing age on saccadic eye movements revealed a linear tendency between increasing age and decreasing maximum velocity. 3. The difference between nasal saccade and temporal saccade was studied. Statistical analysis demonstrated that the maximum velocity of the nasal saccade was faster than that of the temporal saccade and the duration was shorter. 4. The difference of the real excursion angle between the nasal saccade and the temporal saccade was studied. Geometrical analysis demonstrated that the temporal saccade was larger than the nasal saccade.
Neurotological findings of two patients with chronic hepatitis C who developed ver-tigo after interferon therapy are described. The patients were a 62-year-old male who developed dizziness after intramuscular injections of interferon-α and a 55-year-old female who developed positional vertigo after intramuscular injections of interferon-α-2a. Down-beating positional nystagmus was observed in the supine and the supine head-down positions in both patients, but no gaze nystagmus or spontaneous nystagmus was noted. Signs and symptoms were relieved after reduction of the dose of interferon. Elec-tro-nystagmographic (ENG) studies were performed before and after an injection of in-terferon in the female patient. She exhibited hypermetric saccades and increased size of the down-beating positional nystagmus in ENG recorded 6 hours after the interferon in-jection. Several pathophysiological hypotheses about interferon-induced vertigo, in-cluding direct effects of interferon on the central nervous system, are discussed, but they are still to be proved by basic and clinical studies.
We analyzed the results of Schellong tests of 192 patients seen in our out-patient clinic for complaints of dizziness or vertigo. The dizzy patients of indeterminate etiology had a significantly higher incidence of positive Schellong tests than did healthy controls. In contrast, patients with peripheral vestibular disorder had only a slightly higher incidence of positive tests than did normal subjects. These results suggest the following: 1) a substantial number of patients with orthostatic dysregulation or hypotension may be included in the group of patients with diz-ziness of indeterminate etiology; 2) since peripheral vestibular dysfunction generally causes intermittent symptoms, patients with this disorder tend to be asymptomatic or to have an entirely normal physical examination during their visits to the clinic, and test results similar to those of normal healthy individuals; 3) the main drawback of the Schellong test in clinical practice is that a number of healthy subjects show positive results (the false-positive rate was estimated from our previous data to be about 30% in normal subjects). This relatively poor specificity may prevent the obtaining of clear-cut data from the test results.
Two patients manifested reversible acquired pendular eye oscillations after brainstem stroke. Case 1 was a 52-year-old male who was referred to us 5 weeks after an acute event. The CT scan on the day of onset showed severe pontine hemorrhage. Neurotological examination revealed vertical oscillopsia and continuous pendular eye oscillations in the vertical plane, associated with bilateral horizontal gaze palsies. The eye movements had a frequency of about 2 Hz and an amplitude of 7 to 12 degrees. The oscillations lasted more than 2 years. Case 2, a 63-year-old male with blurred vision and dysequilibrium was referred to us. Repeated MRI revealed a venous angioma in his pon-to-medullary junction and no significant interval changes. He had rotary pendular eye oscillations in the frontal plane, associated with synchronous and rhythmic oscillations of the palate. The eye and palate movements had a frequency of about 2.5 Hz and lasted for more than 5 years. Interestingly, although the prognosis has been reported to be poor for the cessation of acquired pendular eye oscillations and diminution of oscillopsia, our patients showed marked improvement 4 (case 1) and 7 (case 2) years after their strokes.
The purpose of this study was to determine reference intervals of the characteristics of the visual-vestibuloocular reflex in healthy subjects. Head and eye movements during active head oscillation were examined. The head was oscillated in the horizontal (H) and vertical (V) planes, and head movements were recorded with a terrestrial magnetism sensor. Eye movements were recorded by an elec-tronystagmographic technique. The examination was performed under the following 2 conditions: a) visual fixation on an earth-fixed target in the light (test for visual-vestibuloocular reflex, VVOR), and b) image fixation on an earth-fixed target in the dark (test for vestibuloocular reflex, VOR). The data were stored on a floppy disc in a microcomputer. From the stored data, transfer function was calculated with head movements as input and eye movements as output in a specially designed program. Five healthy adults were tested. From the data obtained, the mean and the standard deviation were calculated. Results a) VVOR test: (1)The breakpoint frequencies were 3.3±0.5 Hz (H) and 2.2±0.4 Hz (V). (2)The frequency ranges of 180°±10° were 0.2±0.1-0.9±0.2 Hz (H) and 0.2±0.2-0.6±0.6 Hz (V). b) VOR test (1)The gains at 0.1 Hz were-5±2 dB (H) and-3±2 dB (V). (2)The slopes of the gain enhancement were 6±2 dB/dec (H) and 4 ± 4 dB/dec (V). (3)The frequency ranges of 180°±10° were 0.1±0.1-0.8±0.2 Hz (H) and 0.2±0.1-0.6±0.4 Hz (V). The mean±the standard deviation×2 are presented as reference intervals.
The nystagmus-detection rates with Frenzel's spectacles (FS), infrared CCD camera (CCD), and electronystagmography (ENG) were compared and studied. In an examination of 1118 subjects, the nystagmus-detection rate with CCD was 13.2 times higher than that with FS. In 367 of the 1118 subjects the nystagmus-detection rates of all three techniques were compared. When the number of subjects in whom FS produced the same detection rate as ENG, and the number of subjects in whom CCD produced the same detection rate as ENG were compared, CCD was 2.5 times better than FS. The nystagmus-detection rate with ENG was 34.2 times that with FS and 13.5 times that with CCD. Studies and comparisons revealed the advantages and disadvantages of FS, CCD, and ENG. It is necessary to evaluate not only their nystagmus-detection rates, but also each device's merits and to take full advantage of their strengths.