Dizziness is one of the commonest signs in cerebro-vascular diseases. This article describes the occurrence of dizziness in a variety of cerebrovascular diseases. 1) In supra-tentorial lesions the incidence of dizziness was higher in thalamic infarction than in other diseases. Since the thalamic artery originates from the vertebro-basilar (VB) system, it is assumed that circulatory disturbances tend to occur simultaneously in the VB system. Thus, cerebellar and brainstem dysfunction causes dizziness accompanying thalamic infarction. 2) Dizziness due to VB insufficiency (VBI) was the most common central type of vertigo. VBI can have many causes, such as vascular abnormality, vascular compression in the cervical vertebrae, failure of autoregulation in the posterior circulation etc. The diagnosis can be made on the basis of several signs and symptoms, including dizziness. Some characteristic features of the dizziness are short duration, ranging from a few seconds to several tens of minutes ; i. e., reversible dizziness. The most common accompanying symptoms are visual disorders (i. e. diplopia, blurring of vision), headache, autonomic dysfunction, and sensory and motor disturbances. 3) Cerebellar vascular strokes (hemorrhage and infarction) with limited lesions occasionally cause signs and symptoms which mimick those of the peripheral dizziness. CNS signs are not apparent and dizzines, spinning vertigo, vomiting, nausea, and headache are major complaints in such cases. When standing and walking are not possible, and the ocular signs of central abnormality are apparent, one should examine the cerebellum and brainstem with x-ray computed tomography (CT) and magnetic resonant imaging (MRI) to rule out cerebellar stroke.
Since the first reports of endolymphatic hydrops in Meniere's disease by Yamakawa and Hallpike & Cairns in 1938, various attempts have been made to induce endolymphatic hydrops experimentally in animals. We reviewed the literature from 1947 to 1990 on methods of inducing experimental endolympphatic hydrops and summarized these methods on the basis of Schuknecht's classification of human endolymphatic hydrops into progressive and non-progressive types. The progressive pattern of hydrops was induced experimentally in guinea pigs using the silver nitrate cauterization method developed in our department in 1981. This type of experimental endolymphatic hydrops has been found particularly suitable as an animal model of Meniere's disease, since endolymphatic hydrops in Meniere's disease is always of the progressive pattern.
The standing test (Romberg test, Mann's (tandem) test, standing on one foot test) and the deviation test (blindfolded vertical writing test and stepping test) were performed in 111 healthy subjects over 65 years of age, who were divided into 2 groups with respect to activities in their daily lives. The following criteria were got to evaluate the capacity for normal equilibrium in the standing and deviation tests in the elderly Japanese in each age group. 1. Romberg test : Standing posture with eyes open is stable for 30 seconds in those aged 65-79 years and with eyes closed in those aged 65-69 years. Slight body sway is detected in those over 80 with eyes open and in those over 70 with eyes closed. 2. Mann's (tandem) test : With eyes open, the standing posture can be maintained for over 20 seconds in those aged 65-69 years and for over 10sec in those aged 70-79, but it cannot be maintained for 5 sec in those over 80. With eyes closed, standing can be maintained for 5 sec or more in those aged 65-69, and for less than 5 sec in those over 70. 3. Standing on one foot test : With eyes open, standing posture can be maintained for at least 5 sec by those 65-69 years of age and for less than 5 sec in those over 70. With eyes closed, people over 65 cannot stand for more than 5 sec. 4. Writing test : The angle of deviation in under 9 degrees in those aged 65-69 and under 15 degrees in those over 70. 5. Stepping test The angle of deviation is under 180 degrees in those aged 65-79 and under 190 degrees in those over 80.
Optokinetic nystagmus elicited by the optokinetic pattern test (OKP test) in 16 patients with unilateral (13 patients) and bilateral (3 patients) cerebellopontine angle tumors, including acoustic tumors, were analyzed with a computer. The patients were classified into two groups by the greatest diameter of tumor on CT and/or MRICT namely, small (2.0 cm or less) and medium (2.1 to 4.0 cm). The parameters used for ana ysis were total number of nystagmus movements (NYS), total amplitude of the slow phase of nystagmus (AMP), total velocity of the slow phase of nystagmus (S-VEL), and mean velocity of the fast phase of nystagmus (F-VEL). NYS, AMP, and S-VEL values were almost normal or borderline in those with small tumors, but were significantly abnormal in those with medium-sized tumors except in one patient with an epidermoid tumor. AMP and S-VEL had a higher reliability than NYS in predicting the size of the tumors. The value of each parameter (NYS, AMP, S-VEL) on the side of the tumor was not always less than that on the healthy side. On the other hand, F-VEL values did not show any significant abnormalities except in the patient with the largest tumor. There was slight laterality in the F-VEL values. We conclude that this method is useful in predicting the size of cerebello-pontine angle tumors.
Most spontaneous and pendular abnormal ocular movements are congenital, but there are rare cases of similar abnormal eye movements that are acquired. We recently examined a patient with oscillopsia and abnormal ocular movements which started after a head injury. This patient's ocular movements were disconjugated with alternating convergence and divergence. There were no rapid or slow phases, and ocular movement was pendular. During ocular movement there was an increase in convergence amplitude. Disturbances around the Edinger-Westphalnucleus, nucleus cerebelli, and their efferent pathways, etc, were probably involved in the development of this type of abnormal ocular movement.
Twenty three patients with positional vertigo were examined by magnetic resonance imaging (MRI). Abnormal MRI findings (multiple infarction or lacunar infarction) were noted in 11 patients. Vertebrobasilar insufficiency was seen more frequently than benign paroxysmal positional vertigo in patients with abnormal MRI finding.
To determine the effect of fixation point on eye movements during stepping in normal subjects, we used CCD-EOG in a quantitative analysis of eye movements during stepping. This study showed that eyes moved most regularly during stepping when the eyes fixed straight ahead. And eyes moved more regularly during steping when they were fixed 5 degrees downward, or 5, 10 or 15 degrees upward than when they were fixed 10 or 15 degrees downward.
Many investigations have been performed to analyze postural sway. In those investigations the so-called “Center of Gravity (COG)” is usually measured (as many knows, the expression COG is not correct ; the center of foot pressure (CEP) must be used). However, few investigators have analyzed the CFP of the individual foot (ICFP). In this paper, our special interest is the ICFP. Our subjects were 85 non-handicapped persons 20to 60 years of age. They were asked to stand with eyes open or closed and feet parallel, 0, 10 or 20 cm apart. This paper describes only the situation with eyes open and feet 0 cm apart. The trajectories of ICFP were line-like shapes connecting heels and toes. That is, only slight mediolateral displacement occurred. Mediolateral displacement of CFP would result from a change of load on each foot. Anteroposterior displacement, on the other hand, appeared to reduce the CFP range because either of both ICFP ranges was larger than that of the CFP. The relationships between foot length and calculated items were analyzed. There were three different groups with respect to the correlation coefficient and its statistical significance. Strong correlations were determined in mean values of CFP and ICFP. Weak ones were determined in those SDs and ranges. No statistical significance was found in the trajectory length. No strong correlation was found with age.
POLGON (polarized light goniometer) was used to evaluate relative angular changes of shoulders while stepping in patients with unilateral acoustic neurinoma. The mean angular change of shoulders (M. A. C. S.) and its coefficient of variation (C.V.) were selected as parameters of stepping. 1. M. A. C. S. was larger on the affected than on the intact side in patients with those with small tumors (1.0 to 1.9 cm). 2. In those with advanced tumors, both M. A. C. S. were increased. 3. In those with tumors large enough to exert pressure on the midbrain, M. A. C. S. was increased on the affected side. 4. The C. V. was influenced by vision. These results suggest that POLGON is useful for determining the stage of acoustic neurinoma from the viewpoint of disequilibrium.
A 73-year-old male complained of vertigo and/or faintness during mastication. X-ray films showed an elongated styloid process hooked at the tip. A CT scan showed the styloid process compressing the internal jugular vein medially at the level of the first cervical vertebra. The equillibrium test revealed vertical nystagmus downward in the supine position with the head rotated to the right. Positional testing with the head in the hanging position could not be performed because of the sensation of faintness. These findings led us to the conclusion that the styloid process compressed the internal jugular vein, decreasing the outflow from the heart, and resulting in reduced blood flow to the brain giving rise to vertigo. The stylohyoid syndrome consists of neck pain, dull ache in the pharynx, earache and tinnitus, etc, but not vertigo. This is a rare case.
Caloric responses were examined in four patients treated with SM sulfate repeatedly. In three patients, the caloric responses were reduced unilaterally or bilaterally during the first SM treatment and these responses recovered after cessation of SM sulfate administration. A second course of SM therapy was given to these patients. The caloric responses were immediately reduced again. The caloric response in the fourth patient did not change during the first and second course of SM therapy. Audiological examination showed minimal changes in these patients during SM therapy. These results suggest that the caloric response during a second course of SM therapy is easily reduced in those patients whose caloric response is reduced during the first course. Examination of the caloric response is useful in the monitoring of patient for the prevention of SM ototoxicity.
In an investigation of the interaction between proprioceptive and visual information in maintaining upright posture, a stabilometric study was performed with and without vibratory stimulation in 21 healthy young subjects. With eyes closed or open, 100 Hz of vibration was applied for 30 seconds to the triceps surae muscle so that perturbation from proprioceptive information might elicit the tonic vibration reflex. Signals from a platform were filtered by a 10 Hz high-cut filter and digitized at 25 Hz by means of FFT with a microcomputer NEC PC9801 VM-2. When vibration was applied with the eyes closed, a significant increase of the area and length of body sway was noted. Total frequency spectra from 0.1 Hz to 10.0 Hz also increased marked by the sway in antero-posterior direction. Frequency analysis revealed that the increases of power spectra from 2.0 to 4.0 Hz caused more in both the lateral and the antero-lateral sway than when no vibration was applied. With the eyes open, increases above 2.0 Hz affected only the antero-posterior sway. Only sporadic increases were found in the lateral direction. When the eyes-open and eyes-closed responses with intact proprioception were compared, a very significant difference of the power spectrum was noted. These findings suggest that the proprioceptive information plays less of a role than visual input when vision is intact. This afferent input may affect higher frequency body sway, and visual-proprioceptive confict may occur when visual information is available.
Thirty patients with Meniere's disease were treated with endolymphatic sac decompression (Kitahara ; 1974) from April 1986 to October 1989. Ten of them have been followed clinically for two years ; In 10 % of the patient complete control of definite attacks was achieved, and in 90 % substantial control. Hearing improvement at least 10 dB was noted in 20 %, but hearing remained unchanged in 70 % and became worse in 10 %. We considered these results to be satisfactory, and we conclude that epidural shunt operations are useful in controlling vertigo and also in preservating of hearing in patients with Meniere's disease.
It is generally accepted that two different mechanisms underly the generation of optokinetic nystagmus (OKN); an initial rapid rise which is related to the transcortical-cerebellar route and is thought to reflect the participation of the smooth pursuit mechanism and a slower rise of slow-phase OKN velocity that resembles OKN found in nonfoveal animals. Therefore, the pursuit eye movements and the rapid rise OKN velocity would be expected to be impaired in patients with retinal lesions. In the present experiment, both the rapid rise OKN and the smooth pursuit were investigated in patients with retinal lesions with or without hemianopsia. In four subjects who had retinal lesions in and around the fovea, with or without hemianopsia, the rapid rise OKN decreased in response to high velocity OKN stimulation and the gain of pursuit decreased to the upper limits of abnormal values. In a patient who has both foveal lesions and hemianopsia, the gain of the rapid rise was preserved more when the target was moved toward the fovea than when it was away from the fovea. It is concluded that the central retina is very important weight in eliciting the rapid rise and also pursuit eye movements supported by the peripheral retina.