There are many reports of abnormal eye movements as well as neuropathology in Joseph type spinocerebellar degeneration (SCD). However, the relationship of the neuropathologic findings to the abnormal eye movements in this disease is still not clear. The aim of this study was to correlate the clinical signs and neurophysiologic and neuropathologic findings. Our patient, who died at 46 years of age, showed typical neurological symptoms and signs of Joseph type SCD: cerebellar ataxia, dystonic posture, bulging eyes, total ophthalmoplegia, fasciculations of face and upper extremities, and autosomal dominant inheritance. Abnormal eye movements were noted the onset of the disease, and then his eye position became fixed. In the neurophysiological examination, his abnormal eye movements showed that the saccadic eye movement system, especially the generator system (burst neuron system), was destroyed. So the main lesion was considered to be in the lower part of the tegmentum. The postmortem neuropathological examination showed that the neurons in the nuclei for external eye movements, such as the oculomotor, trochlear and ab-ducence nuclei, were relatively spared. However, neurons in the vestibular nucleus, perihypoglossal nuclei, pontine reticular formation and raphe were strongly deciduated and marked fibrous gliosis was seen in these areas. In conclusion, the lesion leading to abnormal eye movements in Joseph type SCD is thought to be in the lower part of the tegmentum rather than in the external ocular nuclei on the basis of both neurophysiological and neuropathological con-siderations.
The precise recording of human eye movements is important in both clinical and basic researches. Many techniqes have been used, but we have found the magnetic search coil method with a soft contact lens to be more convenient than the eye recording systems in common use. We devised a new search coil system based on Remmel's method. In our procedure, the horizontal and vertical fieled coild are driven at 50 and 75 Hz, respectively, by phase-locked square waves. The size of the frame which delivers the magnetic field is 30 cm in diameter. As a sensor eye coil, a newly designed soft contact lens is applied. The lens is made of silicone rubber and is 13.5 mm in diameter. It was tested in normal subjects, and there was no slipping from the eye and no corneal damage. With this equipment, we studied the influence of eye-coil position on gains of both pursuit and saccadic eye movements in 10 normal subjects. The gains were unchanged when the eye-coil position moved within 5 cm in all directions and increased lineay when it moved more than 5 cm. With the use of these data, pursuit eye movements were investigated in an open loop condition. The scleral search coil system of measuring eye movements offers higher resolution, higher linearity, wider dynamic range, lower drift and lower noise, and is more stable than the conventional ENG. The advantage of our system were clearly demonstrated in velocity and acceleration tracings in an open loop condition. In conclusion, our system was found to be ideal for the accurate recording of human eye movements.
The area of the center of pressure (CP) during various activities and the area of CP during maximal voluntary shift to the right, left, back and forth were measured by stabilometry in normal subjects in whom several postures and visual conditions were combined in different ways. When the areas are expressed by circles of πr2 and πR2, the ratio of r to R indicates the capacity of stance correction. The mean value with eyes closed changed from 0.45 for one legged stance to 0.04 for standing with feet apart. The logarithm of r/R decreased lineraly as R increased. Opening the eyes decreased the value of r/R to a fixed ratio irrespective of stance, it was 0.27 when the subject was standing still. Tilting the head increased r/R 1.6-1.9 times irrespective of the stance. However, turning the head or flexing the neck raised the r/R more when the subject was standing with feet apart than when he was standing on one foot. The present study suggests that the value of r/R indicates the ability to regulate stance by the spatial coordinates in the brain. It may be useful in investigations of the regulation of stance to think of the CP area as a scatter on a mark.
The bithermal caloric test was used in the examination of 354 patients with inner ear lesions. The authors caluculated DP% according to Jongkees' formula using the maximum slow phase velocity of the electro-nystagmogram. DP was found in 25% (87/354) of the patients among all the age groups and various inner ear diseases: Meniere disease, sudden deafness, syphilis of the labyrinth, positional vertigo, sensorineural hearing loss, etc. Sensorineural hearing loss was found in 90% (78/87), tinnitus was a complaint in 79% (69/87), repeated vertiginous attacks in 43% (37/87), and fluctuating hearing loss in 26% (23/87).
The peaks and nadirs of stabilogram waves are considered to be the turning points when the direction of body sway changes to the other side. We hypothesized that the number of turning points contributes to an increase of lengh in the statokinesigram. Using the method of pulse analysis, we counted the turning points and measured the amplitude of the pulses of 20 normal subjects, 20 patients with peripheral vertigo and 9 patients with central dysequilibrium. The normal number of turning points was: with eyes open, 31 to 36 in the lateral direction and 25 to 29 in the antero-posterior direction; with eyes closed, 33 to 39 times in the lateral direction and 29 to 34 in the antero-posterior direction. The normal amplitude was: with eyes open, 0.39 to 0.47 cm in the lateral direction and nearly the same in the antero-posterior direction; with eyes closed, 0.46 to 0.54 cm in the lateral direction and nearly the same in the antero-posterior direction. The number of turning points and the amplitude correlated well with the length. Therefore, both indices are considered to be functions of the length. Three of the peripheral patients with vertigo had a high number of turning points in relation to the statokinesigram results, suggesting some patients have a hyperactive postural reflex.
Vestibular symptoms before and after removal of acoustic neurinoma were studied in 47 patients in relation to the origin and size of the tumor and the caloric response. Vertigo and/or dizziness had been noted preoperatively in 26 of the 47 patients (55%). The incidence of such vestibular symptoms was significantly higher when the tumor originated in the superior vestibular nerve (SVN) than when its origin was the inferior vestibular nerve (IVN). No significant difference was seen in relation to tumor size. In patients with a small acoustic tumor or a normal caloric response preoperatively, postoperative vertigo tended to be prolonged. In 9 patients who were operated on through a middle cranial fossa approach, the duration of vertigo after surgery was analyzed further in relation to preservation of the remaining vestibular nerve. When tumors were IVN origin, postoperative vertigo lasted longer when the SVN was resected than when it was those preserved.
Angular acceleration of head movement was measured during stepping in patients with unilateral vestibular disorder (acoustic neurinoma before surgery (pre-AT), 10; acoustic neurinoma after surgery (post-AT), 9; acute peripheral vestibular disorder (APVD), 4). 1) In patients with post-AT or APVD, the amplitude of specified angular acceleration toward the affected side was significantly higher than that toward the normal side. 2) The amplitude of specified angular acceleration showed a negative correlation with the degree of CP (canal paresis) on the calorigram in patients with pre-AT, but a positive correlation in those with APVD. 3) The amplitude of specified angular acceleration showed a negative correlation with the degree of DP (directional preponderance) in Barany's rotation test in all the patients. 4) These findings suggest that the function of the semicircular canals and compensation by the vestibular spinal reflex in patients with unilateral vestibular disorder can be detected by measuring the specified angular acceleration during stepping.
A rare case of complex spontaneous and induced nystagmus is reported. A 68-year-old man complained of vertigo when he turned his head to either side. In addition to jerky type congenital nystagmus, he showed a few remarkable features:1) Nystagmus was directed toward either the left or the right on central gaze.2) Nystagmus was sometimes accompanied by visually induced vertigo. 3) Nystagmus was influenced by head and neck position. These features suggest that congenital nystagmus was accompanied by visual vertigo and influenced by otolith and neck stimulation.
Preoperative and postoperative vestibular function was determined in 9 patients with acoustic neurinoma treated by stereotactic radiosurgery with a gamma unit at Tokyo University Hospital. All of the patients had good vestibular function (CP<50%) before radio-surgery. Seven patients lost the caloric response within 12 months after radio-surgery. When the caloric response diminished, we found symptoms and signs of vestibular disturbance. On the other hand, the hearing level was relatively well preserved. The difference in the degree of preservation between cochlear and vestibular function might be due to the greater vulnerability of the vestibular nerve and its higher dose of irradiation.
It has been demonstrated that chronic exposure to certain visual environments, for example those generated by magnifying lenses and reversing prisms, alter the gain and phase of the vestibulo-ocular reflex (VOR) in the dark in numerous species. Most experiments concerning such modification of the VOR have used semicircular canal stimulation. So far, there has been no investigation of the effect of adaptive plasticity of the semicircular canal-ocular reflex (SCOR) to an off-vertical axis rotation (OVAR), a dynamic otolith stimulation. The purposes of this study are to study physiologic alteration of the VOR using otolithic stimulation and to determine whether the bias and modulation component during OVAR change following adaptation of the SCOR. In this study, using OVAR, we tested the hypothesis that the otolith-ocular reflex (OOR) is altered by changes in the SCOR. Our study showed no convincing evidence for a transfer of SCOR adaptation to OOR using OVAR. There are two possibilities that could explain why we are unable to obtain this evidence, either there is no transfer to OOR, or there is an undiscovered technical problem. Future studies of transfer of adaptation will decrease OVAR exposure and assess OOR variability.
In our neurotological department, the number of aged patients with vertigo and dysequilibrium have increased gradually as the life expectancy rises. Many discussions about the effect of aging on equilibrium tests have appeared but few detailed studies have been reported. In our opinion, activities of daily living (ADL) which are related to equilibrium should be considered when equilibrium changes with aging are investigated. This report describes ADL changes in healthy elderly persons. We sent questionnaires related to equilibrium to 1079 healthy adults and analyzed ADL changes with aging. ADL started decreasing in the seventh decade. The function of the upper extremities almost always remained better than that of the lower extremities, trunk and spine. Furthermore, the ADL of persons who continues work, sports and leg exercise are significantly superior to the ADL of sedentary elderly persons.
The purpose of this study was to clarify the difference of visual influences on lateral and fore-aft body sway in pre-school children. The subjects were 67 children aged 3 to 6 years and 50 adults. Body sway was measured on a force platform in the Romberg position with the eyes open or shut. The RMS value for 512 points of A/D converted data at 50 msec intervals was calculated as an index of magnitude for each of the 2 types of directional sway. (1) The RMS value of lateral sway was significantly higher with the eyes shut than with the the eyes open in 5-and 6-year-old children. The RMS value of fore-aft sway with the eyes open or shut did not differ obviously in the children tested. In adult subjects, the visual conditions had a great influence on both sway directions. The RMS value was significantly higher with the eyes shut. (2) It was also found that under both visual conditions lateral sway showed a definite decrease with age, whereas fore-aft sway did not decrease in preschool children.
Of 169 patients with unilateral sensorineural hearing loss seen from 1991 to 1993, 102 (60%) showed canal paresis(CP), and the etiology was not clear in 51 of them, 25 males (mean age 51.7 years) and 26 females (mean age 58.9 years). Diabetes mellitus was present in 19.6%, obesity in 28.9%, hyperlipidemia in 42.4% and hypertension in 15.7% of those who complained of slowly progressive hearing loss without vertigo, 19 (37.3%) of the right ear and 32 (62.7%) of the left ear. These results suggest that unilateral sensorineural hearing loss with CP of unknown etiology may be the result of a circulatory disturbance of the inner ear due to atherosclerosis.
Twenty patients with labyrinthine fistulae occurring as late complications of radical or conservative radical mastoidectomy had had a long history of postoperative aural discharge and dizziness or vertigo 4 to 64 years following the surgery. Fistula tests were positive in 16 patients. Closure of the fistulae was performed with temporalis fascia alone in 5 and auricular cartilage in 6. Mastoid obliteration by pedicled temporalis muscle with or without hydroxyapatite granules was performed in 6, labyrinthectomy plus mastoid obliteration in 2, and ear canal obstruction in one. In 4 patients, a concomitant postauricular skin fistula was closed. The postoperative course in all 20 patients was uneventful and good.