Proprioceptive organs which regulate muscular tonus through the γ motor system play an important role in the maintenance of body equilibrium. Niki has proved that hypertonicity of cervical and lumbar muscles can be induced through the sympathetic nervous system in certain cases of head and neck injuries. It is conceivable that in addition to the y motor system, the sympathetic nervous system may enhance muscular tonus and thereby. impair body equilibrium, especially when the subject is positive for the equilibrium test with adrenalin loading (hyper-sensitivity of the sympa-thetic component of the central autonomic system). To test the above-mentioned hypothesis, we carried out the following experiments. The equilibrium test with adrenalin loading and the occipital nerve block were carried out in 96 patients with vertigo having the tenderness in the nuchal region. Changes in the righting reflex after the occipital nerve block were examined. The result was such that improvement in the righting reflex was more often observed in patients who had a positive sign in the equilibrium test with adrenalin loading. This improvement in equilibrium is due to the blockade of abnormal impulses through γ fibers and sympathetic fibers which have caused hypertonicity of cervical muscles.
We examined the smooth pursuit systam using two different target movements, (sinusoidal wave and triangle wave) and compared the results quantitatively with a mini-computer (PDP 11/40). The target moved in the horizontal direction with 2 different amplitudes (10° and 15°) and with 4 different frequencies (0.2 Hz, 0.3Hz, 0.4 Hz, 0.5 Hz). The eye movements were recorded with ENG and analysed with PDP 11/40. Three parameters were obtained (movement difference, phase difference, and velocity difference). On normal subjects 3 parameters obtained from the triangle wave became greater than those obtained from the sinusoidal wave, as the target velocity increased. These findings demonstrated that the sinusoidal wave was suitable as the target movement for the examination of the smooth pursuit system.
Eye movements have two factors, that is, quick components or saccades and slow components or pursuit eye movements. A study has been made of whether visual fixation is concerned with saccades or pursuit eye movements. Visual fixation has been examined by the visual suppression test. The eye-tracking test is one of the methods for examining visual fixation, although it evaluates pursuit eye movements. Visual suppression is concerned with both saccades and pursuit eye movements. Visual fixation is composed of two factors, that is, quick eye movements or saccades and slow eye movements or pursuit eye movents.
When ADP was injected into an unilateral vertebral artery in the rabbit, per-rotational nystagmus decreased: slow phase eye velocity (SPEV) of the nystamus beating toward the injected side was predominantly suppressed, and directional preponderance (DP) appeared. The effects of several different drugs e. i phentoxipylline, bencyclane, ATP and ubidecarenone on the ADP-induced VOR dytfuncion were then examined. When bencyclane and phentoxipylline which are known to prevent platelet aggregation were intravenously injected prior to ADP administration, The decrease of SPEV and DP of per-rotational nystagmus following ADP injection became very small. However, when ATP and ubidecarenone which is known to stimulate cerebral metabolism was intravenously injected prior to ADP administration, these two drugs produced no significant effects upon the ADP-induced nystag-mus asymmetry. Microscopic examination revealed total or partial obstruction of a microcirculation in the cerebellum and the dorsal part of the brainstem, by the method of intrvascular injection of a contrast medium. Although administration of phentoxipylline and bencyclane moderately inhibited the ADP-induced obstruction of ricrocirculation, ATP and ubicecarenone offered no protection against the ADP-induced cerebrovascular occulsion
We studied 119 patients with Meniere's disease treated at Osaka City University Dapartment of Otorhinolaryngolgy in the three years from January 1977 to December 1979 with respect to attack conditions, laboratory data and vertigo progress. Schellong's test results for 49 meniére's disease cases whose progress could be observed over 3 months and 26 vertigo patients that were used as controls. 1) Five types of attacks of vertigo and dizziness, B. P (blood pressure), E.T.T(eye tracking test) and O.K. P (optokinetic pattern test)-abnormalities: In Type I, typical attacks (rotary) occured and symptoms completely disappeared after control of the attacks. Included in this type were 6 normotensive and 13 patients with BP abnormality only. Type II resembled type I but featured mild relapse of attacks. This type included 5 patients with BP-abnormality only and, like Type I, no ETT-or OKP- abnomality. In Type III floating sensation persisted for lorg periods after the end of typical vertigo attacks, 9 were with BP-abnormality only, 2 with BP-abnor-mality plus ETT-or OKP-abnormalities, and 4 with BP-, ETT-and OKP-abnormalities. In Type IV floting senstion lasted for long periods after attacks and then rotary vertigo attacks reappeared, after which another floating sensation developed. Observed in this type were 3 patients with BP-abnormality only, 3 with BP-abnormality plus ETT-or O.K.P-abnormality, and 2 with BP, ETT and O.K.P abnormalities. Type V with mild relapse of sttacks, was similar to Type IV and was seen in 2 patients with BP-abnormality only. From the above, BP-abnormality may be considered to be a predisposition of Meniére's disease when it is the only abnormality involved, while complication of cerebrocirculatory insufficiency disease may be considered probable when ETT or OKP-abnormality is added to BP-abnormality. 2) The progress of vertigo, dizziness and Schellong's test for further in vestigation: When only BP abnormality existed in Meniere's disease, both vertigo progress and BP-abnormality improvement went well in many patients. However, in cases where Meniere's disease was supposed to be complicated by cerebrocirculatory insufficiency, floating sensation lasted for long periods after vertigo and BP-abnormality tended to remain unimproved. All the above show that even in Meniere's disease about 20 per cent of the patients had better be-considered. Concomitant cerebrociulatory insuffiency should be treated accordingly.
A 54-year-old female who had complained of a headache on the left side and pain in the left neck was diagnosed as having atlanto-axial dislocation, os odontoideum and platybasia. The posterior atlantoodontoid interval was narrow and the passage of the CSF was blocked at this position when her neck was flexed anteriorly. On the equilibrium function test she was found to have horizontal nystagmus on the right side. Optokinetic nystagmus on the left was poorly developed and eye movement on the eye tracking test was somewhat saccadic. Her right ear suffered from moderate sensorineural hearing loss. However, the result of the caloric test within the normal range for both ears. Widening of the fossa magnum, C1 laminectomy and the fixation of occipital bone C2, C3 were performed. After the operation and several months of head traction, her complaints and nystagmus disappeared. From these data we have concluded that the area responsible for her nystagmus and disequilibrium was located around the right pontine gaze ceter. It appeared that the center was mechanicaly compressed and / or ischemic due. to the compression of the vertebrobasilar artery.
Various utilizations of VEPs are reviewed by the author's investigations. Short latency VEPs are recordable from the temporal area of the scalp but the electrogenicity of these wavelets which are similar to the auditory brainstem reaction is not yet established. The luminance VEPs has meaning if the defective amplitude or delayed P100 latency is recognized. The pattern VEP including spatial frequency grating is useful as an objective measure for gross estimation visual acuity. Visual recognition and visual selective task appear the P200 and P3oo component respectively from the vertex area. These late potentials are experimentally significant in detecting a high grade vision. For the objective visual field examination, a moving grating target of 5°-10° of subtending angle can evoke a steady state VEP even from a peripheral field and it is interpreted that the potential is elicited from the Y channel. For the determination of stereoptic VEP, the liquid crystal shutter and a real stereo target are used. The amplitudes of binocular VEP are enlarged to about 2 times (√4 times) the monocular VEP.
Eye movements can be functionally classified into suprauclear and infranuclear, conjugate and disjunctive, or pursuit and saccade. From the neuroophthal mological point of view, routine examination methods of eye movements consisted of the following: (1) confrontation observation, (2) electromyogram of the extrinsic eye muscles, (3) electro-oculog-ram (EOG), (4) photoelectric oculogram (PEOG), (5) image analysis system using infra-red television fundus camera (IRTV). After description of individual methods, several clinical cases of abnormal eye movements were presented, in which the etiology could be definitely diagnosed by administering each examination. For example, the etiology of Duane's retraction syndrome was speculated on the basis of the electromyogram to be supranuclear paradoxical innervation between the oculomotor and abducens nucleus. When comparative studies of three eye movement recording systems between EOG, PEOG and IRTV were made, it was shown that the IRTV is the most accurate method for demonstrating the small displacement of eye position, and PEOG is more sensitive than EOG, and PEOG is the most useful method for analysing the maximum saccadic velocity and eye position. Finally, the author mentioned electrophysiological characteristics and muscle representation of the oculomotor nucleus of the cat which were produced antidromically by electrical stimulation of the oculo-motor nerve branches in the orbit.
Reflex blinks, i. e, the protective reflex movements in closure of the lids, are evoked by several stimuli, such as touch, flash of light and click sound. Through the electrophysiological experiments using cats, the mechanisms involved in the reflex pathway were revealed to be as follows: 1) The pathway of the tactile reflex blink has two routes. One is the oligo-synaptic arc which connects the main sensory trigeminal nucleus to facial motor nucleus directly. Another is the multisynaptic arc with the connection to the pontine reticular formations which may play an important role in the protective function. 2) The pathway of the photic reflex blink takes the route of ventral nucleus of the lateral geniculate body, pretectum, mesencephalic reticular formations, pontine reticular formations and facial nucleus. The contra-lateral route crosses over the supra-optic commissurae. 3) The pathway of the acoustic reflex blink is the multi-synaptic route which consists of ventral cochlear nucleus, superior olivary complex, nucleus of the lateral lemniscus, mesencephalo-pontine reticular formations and facial nucleus. The contralateral route crosses via the trapezoid body. The coincidence of this reflex pathway in the human may be revealed by the clinical application to the patients.