From 1971 to 1984, 27 patients with Mdniere's disease were treated surgically at Kitasato University Hospital. The 15 treated with Rosen's operation, section of the chorda tympanic nerve, had frequent recurrences of vertigo soon after surgery. In nine of these patients the attacks stopped within one year after the operation, in three patients they stopped one to two years and in one patient two to three years after surgery. However, in four patients vertigo recurred later. In two patients the operation had no effect. Of the 10 patients treated with Portmann's endolymphatic sac operation, success was achieved in only five : cessation of attacks of vertigo and preservation or improvement of hearing. All three patients treated with labyrinthectomy after Rosen's operation, had trouble later in the nonoperated ear. A new metdod of determining the efficacy of treatment was devised microcomputer to measure the differences in the mean interval between two successive attacks and in the mean hearing level before and after treatment. These were evaluated statistically at the level of 5% error.
The clinical symptoms and signs of two patients with convergence nystagmus are described, clinicalsymptoms and signs, and the mechanism of convergence nystagmus is discussed from the viewpoint of the results of otoneurological studies The first case was a 20-year-old male whose chief complaints were indistinct consciousness and visual disturbance. Radiographic examinations and neurological tests revealed cerebral atrophy, dilatation of the lateral ventricles, a low density area in the right occipital region and marked narrowing of the right posterior cerebral artery. Neurological signs were left homonymous hemianopia, paralysis of upward gaze, convergence nystagmus, cerebellar symptoms and left hemiplegia. The diagnosis was cerebral vescular lesions with multiple thromboses. The second case was a 37-year-old female, who had developed motor disturbances, dysarthria and dysphagia. There were marked cerebellar signs, atrophy and fasciculation of the tongue, muscle atrophy and pathological reflexes. Oculomotor signs were paralysis of upward gaze and convergence nystagmus. The diagnosis was Marie's cerebellar degenerative disease. In these two cases convergence nystagmus seemed to indicate that the responsible lesions were located in the periaqeuductal region of the midbrain, quardrigeminal plate and oculomotor nuclei. The mechanism of convergence nystagmus appears to be an overflow of impulses to the medial recti centers.
We examined the effect of eye tracking stimulation on movement of the body's center of gravity (CG) in patients with Ménière's disease using a strain gauge platform and a minicomputer. 1) Two types of locus pattern of the CG were observed while eye tracking: a left and right type in 7 subjects and a centripetal type in 5 subjects. In the centripetal type, the total length of movement of the CG while standing for one minute gradually increased with increasing traget speedsup to 0.5 Hz and then decreased at higher speeds. However, in the left and right type, therewas little change of movement of the CG at speeds above 0.75 Hz. 2) On horizontal stimulation the Y/X ratio gradually decreased with increasing frequency of traget speeds up to 0.5 Hz. On vertical stimulation the ratio was above 1.0 at all traget speeds in the centripetal type, but was below 1.0, except at 0.25 Hz, in the left and right type. 3) The frequency spectra obtained from CG movement while eye tracking changed in the range below 1.0 Hz and sometimes showed several peaks at around 0.2 Hz. The average spectral frequencies were calculated and some characteristic results were obtained, related to the types of the locus.
The equilibrium function of children develops with their physical growth, and its estimation must be performed by appropriate examinations. This study deals with the changes in body sway strating at 4 years of age. 1. The area and locus length traced by the body's center of gravity decreased with age, and children 12 to 15 years of age showed nearly the same values as adult subjects Changes in the velocity of body sway paralleled those of the area and locus length. 3. In right-handed children, the moving area of the center of gravity was mostly to the left of the center line in the standing horizontal plane.
In an examination of the vestibular function of patients with unilateral deafness, simplified caloric tests were performed on 35 patients who had been followed in the ENT clinic of Tokyo Univ. Hospital. Among the three parameters employed, i. e., latency, duration and frequency, duration had the highest fidelity of vestibular response. The results of caloric tests were not significantly different between the deaf ear and the normal ear not only as to duration but also as to latency and frequency. In 13 of the 35 patients, the etiology of the deafness had been mumps, and in these patients, who had not experienced vertigo, there was no significant difference in the caloric response between the deaf and the normal ear. On the contrary almost all patients with delayed endolymphatic hydrops and vertigo had a depressed vestibular response in the deaf ear. It is concluded that the cochlea is more vulnerable to injury than the vestibule.
The criptospinal reflex or laterotorsion, an expression of vestibulo-spinal reflex after caloric stimulation, can be demonstrated by a newly developed device, an "Encorder", i. e. a rolling photosensor, connected to a microcomputor and a printer. Three parameters, i. e. axis rotation, wipering action and sliding side to side are yielded online by this device. After cold irrigation (30°C), almost all normal subjects showed laterotorsion towards the slow phase of caloric nystagmus, one third showed laterotorsion towards the slow phase of "Heisswasser-Nystagmus" (Bárány). The patients with moderately or highly depressed vestibulo-ocular responses, however, showed remarkably good laterotorsion, which could prevent the occurrence of "jumbling" in the latter.
Of the 441 patients of Meniere's disease treated at the Neurotology Clinic of Toranomon Hospital from 1969 to 1983, 330 were observed for a long time. The longest period of observation was 15 years. 1. Changes of symptoms and functions 1) Hearing: same. . 72%, improved. . 15%, worse. . 13%. 2) Vertigo: no vertigo.. 57%, very mild dizziness 43/%. 3) Caloric test: same. . 95%, worse. . 5%. 2. Bilateral Ménière's disease appeared in 24 cases cases (5%). 3.Therapy 1) Conservative therapy 2) Patients with frequent vertigo attacks When the glycerol test was positive, endolymphatic sac surgery was performed. When the glycerol test was negative and hearing was preserved, streptomycin sulfate infusion of the middle ear was performed. When the hearing impairment was severe, labyrinthectomy or VIIIth nerve section was done.
To examine the predictive function of smooth pursuit. the authors developed a new target wave, the random sinusoidal wave. The random sinusoidal wave consists of 40 half sinusoidal waves with 5 degress of amplitude and is divided into two sections, the predictive section and the nonpredictive section. The predictive section contains the usual sinusoidal waves. However, the direction of the sinusoidal wave proceeds to the unusual (opposite) side in the nonpredictive section. Eve movements were recorded twice (in the first examination and the second examination) with the random sinusoidal wave. The test was evaluated in 23 healthy subjects. Five parameters in each of the two sections were calculated quantitatively with a microcomputer and the results of the first and second examinations were compared. There were no differences between the five parameters in the first and second examination in either the predictive or the nonpredictive sections. These results confirm the reproductability of the smooth pursuit examination with this target wave.
A 35-year-old male with bilateral acoustic tumors (case 1) and a 48-year-old male with a left acou-stic tumor (case 2) had severe hearing loss on the affected sides but caloric test results were normal. At operation a well-preserved vestibular nerve was confirmed in the auditory meatus in case 1 In case 2 vestibular and facial nerves could be preserved after total removal of the tumor. Those findings explain why the caloric responses were normal in both cases.
The lateral semicircular canals of bull frogs were isolated and the cupula was removed from the crista and the sensory cilia on the crista were depressed toward the utricular side by a glass micropipette. Five points on the crista were selected for stimulation. Decremental time constants of the lateral ampullary nerve action potentials were measured. The longest time constant was obtained from stimulation of the wide portion of the crista. The time constant progressively decreased as the narrow side of the crista was approached. These results indicate that the lateral semicircular canal crista is equivalent to the halved posterior semicircular canal crista in terms of both morphology and physiology.
Six healthy young adults were selected to examine the influence of blindfolding one eye on the production of horizontal saccadic eye movements under a monocular lead. A saccade-evoking apparatus (Nagashima K-N 50) was used to induce random saccades. Standard electronystagmography with a time constant of 3.0 and a paper speed of 50 mm/sec was emplo. yed for the recording of eye movements. Two main characteristic findings were obtained with both eyes open: the volocity of the saccades increased in proportion as the amplitude of the saccade rose, and the velocity of adduction was significantly faster than that of abduction. Under unilateral blindfolding, the saccades towards the blindfolded eye showed no difference of velocity between adduction and abduction and no significantly increased velocity although the amplitude increased. However no significant change was noted in saccades towards the non-blindfolded eye. The neural pathways responsible for this finding are considered.
The cerebellar flocculus of the cat be divided into three zones (rostral, middle and caudal) anatomicaly and physiologically. The rostral zone receives climbing fiber input from the rostral part of the dorsal cap and the ventrolateral outgrowth, and sends output to the central part of the superior vestibular nucleus. The middle zone receives climbing fiber input from the caudal part of the dorsal cap and sends output to the medial vestibular nucleus. The caudal zone receives climbing fiber input from the ventrolateral outgrowth and the rostral part of the dorsal cap, and projects to the Y-group and the medial part of the subnucleus lateralis parvocellularis of the lateral cerebellar nucleus, Activation of the rostral, middle and caudal zones produces an upward, an ipsilateral horizontal and a downward eye movement, respectively.
From May 1984 through April 1985, 20 patients visited our clinic for the first time to seek help for tinnitus without concurrent vertigo. These patients had nystagmus tests with Frenzel's glasses and stepping tests in addition to audiometry. At the time of the first examination, 18 of these 20 patients displayeda nystagmus, 17 showed an angle of rotation of more than 30° in the stepping test, and only 1 demonstrated neither nystagmus nor deviation. These findings are interpreted as suggesting that many patients with severe tinnitus have a lesion not only of the cochlea but also of the vestibule and are in a condition similar to an attack of Meniere's disease. For these patients with tinnitus, rest was prescribed as for those with an attack of Mdniere's disease, with oral steroids administered when tinnitus was especially severe. After 1 to 2 weeks of this regimen 17 of the 20 patients were entirely freed from or relived of tinnitus and no longer exhibited nystagmus and deviation. Four patients in this series had normal hearing and hence their condition was thought to correspond to 'tinnitus without hearing loss.'
We performed psychological tests, the Cornell Medical Index (CMI), the Yatabe-Guilford Personality-Test (Y-G Test) and the Rosenzweig Picture Frustration Study (P-F Study) to evaluate psychological factors in patients with peripheral vestibular disorders. 1) Some of the patients with peripheral vestibular disorders had CMI type III and IV scores, but they showed a stronger neurotic tendency than normal subjects.The neurotic tendency was more evident in males than in females. Furthermore, "anger" of psychiatric items was characteristic of the patients. 2) Most of the patients with peripheral vestibular disorders showed Y-G type A and D results, and emotional stability, but some of them had Y-G type B and E results, and emotional instability. 3) Personality characteristics of the P-F Study were lack of common sense and reflection, aggressiveness and dependence.
Nystagmographical.examination with a long recorcling portable electronystagmograph was carried out in a patient with vestibular neuronitis. Nystagmus was the direction-fixed nystagmus beating to the healthy side in both the first and follow-up examination during the course of the illness. In the first examination, two days after the onset, nystagmus was recorded frequently. In the follow-up examination, eight days after the onset, nystagmus was recorded only before falling asleep at night and arising early in the morning. The long recording portable electronystagmograph may be useful to monitor the course of vestibular neuronitis.
Transient ocular deviations with eyes closed were observed electronystagmographically in 20% of normal adults on trunk rotation without neck torsion. These were in the same direction as the rotation. The average angle of deviation was less than 15°. These reflex deviations were probably not elicited by input from the vestibular system but from the proprioceptors because they decreased in 9.1% when the head was bent 30° forward but were not affected by bending 60° backward or changing the velocity of rotation. Transient ocular deviations were less frequent and smaller on trunk rotation than on head rotation with neck torsion.
Galvanic nystagmus and the sway of the body center of gravity (galvanic body sway) were used to differentiate between otoliths and semicircular canal lesions in patients with bilateral loss of labyrinthine excitability. Methods. Galvanic stimulation was performed by the biaural-bipolar method. (1) Galvanic nystagmus induced by application of a direct current of 3 mA for 60 seconds was counted macroscopically. (2) The subject was instructed to stand on a stabilometer, and galvanic body sway was examined by galvaniza-tion at 1 mA for 6 seconds. Results. One patient did not show any galvanic nystagmus. but had normal galvanic body sway. Two patients had opposite results. Clinical symptoms and other balance tests, such as the standing test, suggest that galvanic nystagmus reflects mainly the reaction of the semicircular canal system and body sway mainly the reaction of the otolith system. Such phenomena are explained as follows : First, it is considered that although both the canal system and the otolith system can cause ocular reflexes and spinal reflexes, the main role of the canal system is to cause nystagmus, while that of the otolith system is to cause spinal reflexes. Second, in the canal system, the kinetic reaction is superior, with a high threshold for galvanic stimulation, which makes it difficult to observe spinal reflexes from the canal system, while in the otolith system the tonic reaction is superior, causing spinal reflexes at a low threshold. The results indicate that it is possible to differentiate lesions of the semicircular canal system from those of the otolith system by analyzing galvanic nystagmus and body sway.
In 157 patients with unilateral peripheral vestibular disorders, the positional nystagmus test and the computerized trapezoid rotation test were performed periodically and their value as follow up vestibular examinations was compared. Positional nystagmus was examined by ENG with Frenzel's glasses, and the trapezoid rotation test was performed with Contraves' computer rotary chair system 1) Abnormalities were detected in 59.2% by the rotation test and in 26.8% by the positional nysta-gmus test. 2) The tests were repeated periodically in 42 patie-nts. The labyrinthine preponderance detected by the rotation test was observed for a long time after the disapperance of positional nystagmus. 3) In cases of episodic vertigo, such as Meniere's disease, periodic tests with the computer rotary chair system could forecast the time of the next attack and make it possibility to prevent the attack.