Medical doctors and physical therapists in rehabilitation medicine in Japan have paid little attention to the rehabilitation for dizzy patients or patients with disequilibrium. However, vestibular rehabilitation or physical training of patients with chronic vestibular disturbances has been investigated and considerable clinical experience in this field has accumulated in the United States and Europe since Cawthorne's report in 1946. Fortunately, in 1990 "Standards of vestibular training" was published by the Japan Equilibrium Research Association, with the goal not only of improving the quality of life with bilateral labyrinthine destruction, but also of decreasing dizziness and disequilibrium provoked by head and body movements of dizzy patients. The published fundamental biological and medical studies on physical training, practical methods and description of exercises are reviewed in this paper. The author urges further studies of vestibular training and hopes that welfare services for dizzy patients will be greatly expanded.
A case of bilateral MLF syndrome with exotropia due to brain stem infarction is reported. A 77-year-oldwoman developed sudden diplopia with dizziness. Ocular motor findings on admission were : On forward gaze, she used only the right eye, and the left eye was in the full abduction position;she could adduct the left eye to the midposition when using it for fixation ; leftward gaze evoked left-beating nystagmus of the left eye, but the right eye did not adduct ; righward gaze evoked right-beating nystagmus of the right eye but the left eye did not adduct; on upward gaze, right eye movement was in-sufficient ; downward gaze was possible ; convergence was insufficient. MRI (T2 weight spin echo image) displayed a high signal intensity area in the midbrain teg-mentum, but the pons was intact. On the basis of these findings, the diagnosis was intact. On the basis of these findings, the diagnosis was bilateral MLF syndrome with non-paralytic exotropia. The lesion in this case may be bilateral MLF and right oculomoter nucleus disorder. The exotropia of this patient may have been due to bilatreral dysfunction of the MLF and hyper-function of the left paramedian pontine reticular formation (PPRF). The difference between paralytic pontine exotropia (PPE) and non-paralytic pontione exotropia (NPPE) is also discussed in this paper.
Our patient had had positional nystagmus of the central type for 17 years. At the age of 52, he had a sudden onset of vertigo and gait disturbance. Since then, we had the chance to examine him once every two weeks. Horizontal and rotatory nystagmus directed to the left was always observed when his head was turned or hung down and twisted to the left. The nystagmus was provoked without latency and lasted as long as these positions were kept and neither decreased or habituated. At the onset of his disease, optokinetic nystagmus (OKN) was provoked poorly and the eye tracking test (ETT) showed a saccadic pattern. As his course progressed, OKN was easily provoked, and ETT showed a normal pattern. CT-scans showed no abnormality, while MRI revealed ischemia of the left cerebellar hemisphere including the fastigial nucleus, and the middle cerebellar penduncle including the juxtarestiform body. Considering the hypothesis of the mechanism of positional nystagmus of central origin, the pathogenesis of his nystagmus could be the ischemic degeneration of the fastigial nucleus and juxtarestiform body.
The mechanism of the development of equilibrium skills was studied in subjects standing on a balance-board, somersaulting during gymnastic exercises and performing ballet rotations. 1. The ability to stand steadily on a freely movable balance-board was achieved after several days practice. The records of sways of the head and center of gravity of the body and activities of the nuchal and soleus muscles indicat that maintenance of a steady standing posture was possible because labyrinthine and proprioceptive postural regulations became precise. The training effect was due to facilitation of the postural reflexes through the brainstem and spinal cord. 2. A somersault requires a chain of postural reflexes : visual fixation, labyrinthine righting reflex upon the head, and tonic neck reflex. We conclude that the basal ganglia and cerebellum play important roles in the formation of this chain of postural reflexes. 3. Eye and head movements during ballet rotation with spotting technique were studied using a telemeter in a beginner and a trained dancer. During the trained subject's rotation, eye movements induced by optokinetic and la-byrinthine-ocular reflexes appeared to be under voluntary control. The ballet rotation was a movement that postural reflexes were inserted into a chain of voluntary movements carried out by a central program formed by training. The cereberal cortex was involved in this central programming. In the functional development of body equilibrium by training, the degree of participation of the central nervous system varied depending on kinds of exercises trained : the cerebral level in ballet rotation, the basal ganglia and cerebellum level in somersaults, and the brainstem and spinal cord level in standing posture.
We tested the range of visual fixation during head oscillations in a group of normal subjects who were asked to fix a visual target during oscillation of the head in the horizontal and vertical directions. Head and eye movements and the sum of both movements were recorded with a polygraph and stored in a microcomputer. To detect head and eye movements, we used a specially designed photodetector and an electronystagmographic method respectively. From the stored data, transfer function was calculated with head movements as input and eye movements as output. The normal range was defined as the mean and the standard deviation of the results. Eleven healthy male and female adults were tested. (1)The normal range obtained from polygraph records was 3.6Hz in the horizontal direction and 2.2 Hz in the vertical direction. (2)The normal range obtained from transfer functions was 4-5Hz in both horizontal and vertical directions.
A careful analysis was made of the results of electronystagmography in 3 patients with spontaneous vertical nystagmus, and the causes of their nystagmus are discussed. Case 1 : a 24-year-old man showed primary position upbeat nystagmus with large amplitude (4°-6°) and 2 Hz frequency, which decreased on upward gaze and increased on downward gaze. This nystagmus changed to downbeat nystagmus when convergent gaze was maintained. Marked bilateral diminution of vestibular response was noted during rotation tests and caloric tests. Case 2 : an 80-year-old man had primary position downbeat nystagmus at a frequency of 1.5Hz and an amplitude of 2°-4°, which was not influenced by changes of eye position. Vertical optokinetic nystagmus tests were abnormal, but other neuro-otological findings were almost normal. Case 3 : a 47-year-old woman showed primary position downbeat nystagmus with small amplitude (1°-2°) and 3 Hz frequency, which increased in intensity in the supine right-side-down position and changed to an upward vector in the head-hanging-position. VOR gain was greater than normal. There was almost total absence of visual suppression of caloric nystagmus. The nystagmus observed in Case 1 seemed to reflect bilateral dysfunction of the caudal brainstem, including both vestibular nuclei, resulting from Wernicke's encephalopathy. The nystagmus in Case 3 originated from caudal brainstem compression by a large menigioma. In Case 2, no diagnosis was established.
Five cases of unilateral dilatation of the internal auditory canal with positive neuro-otological findings are presented. Acoustic neurinoma was ruled out by MRI or CT. The unilateral dilatation of the internal auditory canal was thought to due to so-called patulous canal in one patient and to neurofibromatosis in one. It appeared to be a normal variant in three patients. In patient with a patulous canal, there was ballooning of the internal ear canal. The causes of the ipsilateral positive neuro-otological findings were unknown. Undoubtedly, temporal bone tomography and neuro-otological examinations play important roles in the diagnosis of acoustic neurinoma, but we should consider the possibility of misdiagnosis due to false positive results of these examinations. The final diagnosis of acoustic neurinoma must rely on MRI findings.
Horizontal and vertical pursuit eye movements were analyzed quantitatively in normal subjects with the use of a charge-coupled device (CCD)-electro-oculogram. Parameters adopted for the qualification were coherence function and phase. As the speed of the target increased, the difference in phase between the target and both horizontal and vertical eye movements became larger. However, there was no significant difference in phase between horizontal and vertical eye movement. Quantitative frequency analysis of pursuit eye movements showed that eyes follow a horizontally moving target more accurately than a vertically moving target. When a target is moved vertically in the upper half of the field, the eyes follow it less accurately.
Vertical oscillopsia, dysequilibrium, ataxic gait, truncal ataxia and dysarthria were noted in a 20-year-old male with a 4-year history of daily toluene abuse. CT and MRI of the brain revealed no atrophy of the cerebrum, cerebellum, or brainstem. However, T2-weighted MRI demonstrated a high intensity area bilaterally in the pontine corticospinal tracts. Pure tone audiogram and SISI were normal. The I - V interpeak latency of ABR was prolonged bilaterally. Vertical nystagmus was noted during positioning and positional tests. ENG revealed saccadic pursuit, poor OKN and failure of visual suppression of caloric nystagmus. The patient's neurological symptoms disappeared. Follow-up neurotological examinations demonstrated improved ENG findings. However, subclinical deficits remained in ABR and stabilometric tests.
In 1957, Bickerstaff described eight patients with a syndrome consisting of a prodromal malaise and a downward progression of mid-brain disturbance resulting in almost total suppression of all functions having brain stem innervation but no cardiac or respiratory disorder. Maran described a similar case and introduced the title Bickerstaff's encephalitis. Subsequently there have been many reports of similar nature, but no detailed neourotological examinations have been conducted. We describe here a 60-year-old male, who showed most of the features described by Bickerstaff. Computed tomography of the brain was negative. Neurotological examinations revealed functional disturbance in the cerebellum and brain stem, including cerebellar ataxia, central bilateral vestibular deficits, abnormal findings in optokinetic nystagmus test, etc. There was a dissociation in the results of two tests of the vestibular system : abnormal caloric test with normal galvanic body sway test. It was assumed that area of disorder in the vestibular nucleus was localized. These examinations results recovered as the signs and symptoms abated. It is concluded that neurotological examination is very useful in the diagnosis and in the evaluation of therapy in Bickerstaff's encephalitis.
The origins of efferent vestibular fibers to otolith organs (mainly as macula utriculi) in guinea pigs, examined with the retrograde transport of horseradish peroxidase (HRP) were : (1) bilateral lateral portions of the facial genu and (2) ipsilateral reticular nucleus at the level of the facial nucleus. these origins are almost the same as those of the efferent fibers to the three semicircualar canals which we previously identified in cats, but they differ in some details.
The present study was designed to evalute the influence of aging on movement and posture. A group of 30 elderly subjects and a group of 30 younger subjects were given a stepping test at different speeds (0.8, 1.0, 1.2, 1.4, 1.6 Hz) produced by a stepping recorder, and single support time and double support time were evaluated as parameters. A statistically significant difference was noted at 0.8, 1.2, 1.4, and 1.6 Hz in the single support time. Similarly, a statistically significant difference was noted at 0.8, 1.2, 1.4, 1.6 Hz in the double support time. It is concluded that aging exerts an influnce on the posture and movement con-trol systems even when the results of ordinary stepping tests are normal.
The relationship between the plasma concentration of atrial natriuretic peptide (ANP) and the clinical aspects of Meniere's disease was examined. In almost all patients, the plasma concentration of ANP was within normal limits, but in those with fluctuating hearing levels, it was significantly low. There may be some relationship between unstable Meniere's disease and low plasma concentration of ANP.
This study was designed to evaluate the effects of atrial natriuretic peptide (ANP) on the cochlear blood flow (CBF) of normal guinea pigs and of guinea pigs with experimentally induced endolymphatic hydrops. ANP was administered intravenously and the CBF was measured with a Laser-Doppler-Flowmeter. When ANP was injected for 15 minutes, the CBF of guinea pigs with hydrops induced 4 weeks previously was higher than that of those with hydrops induced 12 to 16 weeks previously. When ANP was administered in large quantities for one minute, the CBF at 10 minutes was slightly higher in hydrops induced guinea pigs than in normal guinea pigs. The mechanism in normal and in hydrops induced guinea pigs after ANP administration appears to be different.
A new technique was designed for vestibular testing with an air caloric stimulator. With this technique, the temperature threshold necessary to induce caloric nystagmus was measured at decreasing air temperatures (from 37°C) at a constant velocity. As a pilot study, the air caloric test with continuous thermal change was carried out at 6 different decreasing speeds ; 0.01, 0.03, 0.05, 0.1, 0.15 and 0.2 deg/sec. The speed of 0.05 des/sec gave the minimum standard deviation of temperature threshold in normal subjects. No side effects were observed during or after the air caloric test with continuous thermal change at this speed. The new air caloric test also showed the narrowest normal limits among the ordinary caloric tests hitherto reported.