Nystagmus Reaction Research Articles

Galvanic test in central vestibular lesions.

1. Brainstem lesions without presence of a spontaneous vestibular nystagmus generally do not show any particular change of the pattern of the galvanic nystagmus reactions.2. In brainstem lesions with presence of a spontaneous nystagmus the threshold of the galvanic nystagmus is mostly normal whereas supra-liminar tests invariably show a pathological reversal phenomenon. Sometimes a relatively high incidence of abnormally increased amplitude and frequency values can be found, a phenomenon which is not observed among other groups.3. Cerebello-pontine angle tumours (acoustic neuroma excluded) show either a normal or only moderately raised nystagmus threshold.4. In supratentorial lesions of the brainstem the pattern of liminar and supraliminar galvanic responses is not characteristic.5. In lesions of the cerebral cortex threshold values are normal among the majority of the cases but supraliminar tests reveal a relatively high incidence of pathological directional preponderance towards the side of the lesion, ...

Clinical observations of vertigo following head injury

The author have studied in 274 cases with posttraumatic vertigo from the observation of optokinetic and vestibular nystagmic reaction. The results obtained are summarized as follows;1) Of the total 274 cases, the spontaneous nystagmus was observed in 138 cases (49%) and the positional nystagmus in 190 (69%).2) Pathological findings of optokinetic nystagmus, for example, optokinetic inversion, inhibition or interruption of optokinetic nystagmus, hyperexcitability of optokinetic secondary phase, dissociation between the direction of optokinetic and vestibular DP, were highly observed in patients in cases with the central damage. Therefore, the test of optokinetic nystagmus is of vital importance for differentiation of posttraumatic vertigo.3) By the test for torsion or extension of the neck, nystagmus was frequently provoked especially in cases with central damage, therefore, this test is of vital importance for the diagnosis of posttraumatic cervical syndrome.4) To speak the singularity of posttraumatic vertigo, the following will be mentioned.(1) The determination for the localisation of the lesions is usually difficult.(2) Most of these cases have no neurological findings.(3) Pathological nystagmic reaction was only observed in cases of the brain-stem lesions.(4) Symptoms and nystagmic reaction are unsettled for long period of time.

Habituation to complex vestibular stimulation in man: transfer and retention of effects from twelve days of rotation at 10 rpm.

Nine men rotated at 10 rpm for 12 days. Control Ss were tested at comparable intervals. Tests conducted before and after the 12-day run demonstrated that nystagmus and subjective effects produced by head movements during the accustomed direction of rotation (CCW) had diminished markedly, whereas during CW rotation, 1 hr. after the 12-day run, nystagmus and subjective reactions approximately equaled reactions prior to the 12-day run. The unequal reduction was attributed to conditioned compensatory reactions. Two days later, responses to both rotation directions were suppressed as compared with initial levels of response; compensatory reactions had apparently dissipated. Some response decline was still present after 3 wk. rest, but tests after 3 mo. revealed considerable recovery toward initial response levels. Reactions to passive whole-body angular acceleration were not greatly altered by the 12-day run.

On the Changes of Nystagmus Caused by Ultrasound-Produced Focal Lesions in the Brain-Stem

Results obtained are summarized as follows: (1) The presence of both the medial longitudinal fasciculus and ponto-mesencephalic reticular formation is of vital importance in the evocation of normal nystagmic reactions. (2) The ponto-mesencephalic reticular formation has the nystagmic controlling mechanism which produces a phasic rhythmic neural activity, especially the reticular formation on the level of nucleus motorius nervi trigemini plays an important role for the occurrence of vestibular nystagmus. The author infers that a nystagmic eliciting centre is located in it. (3) Optokinetic fibre tracts have no direct innervation with vestibular tracts in the brain-stem. (4) The destruction of the reticular formation just below the nucleus trochlearis causes the optokinetic inversion.

The vestibular system.

Recent progress in the vestibular system has included research into vestibular function and clinical considerations. Vestibular Function Special interest has continued to be centered on the phenomenon of habituation as demonstrated in the vestibular system. Habituation or response decline are terms used here to indicate that one or several parameters of nystagmic reaction, such as duration of the reflex or velocity of the slow component, diminishes as vestibular stimulation is repeated. The experimental evidence indicates that habituation of vestibular reflexes is a central phenomenon presenting, as in a learning process, the characteristics of acquisition, retention, and transfer. The term stands for the progressive decrement of the nystagmic response. The extent of acquisition may range from moderate response decline to extinction. The term is used for indicating long-lasting persistence of the neural process underlying the response decline. It is the most important characteristic, because without retention the phenomenon of

Perceptual and Oculomotor Reactions to Interacting Visual and Vestibular Stimulation

Abstract : Six men received repeated vestibular stimulation under several conditions of visual stimulation. Nystagmus, suppressed during brief room illumination, recovered almost completely in a following period of darkness; the subjective response remained suppressed. A small light (or large fixation field) inhibited nystagmus but did not suppress the subjective response. Apparently any visual still fixation field suppressess nystagmus, but the subjective response depends upon visual sensory information denying relative motion between the fixation field and the earth; intellectual information alone is ineffective. Nystagmic and subjective reactions diminish with repeated rotation. Only the subjective reaction recovered after a 9-day rest. (Author)

The caloric test in the cat.

A simple device for fixing both head and body of the cat was designed so that the nystagmic reaction to caloric stimulation could be investigated. Nystagmographie tracings of both ordinary and derived nystagmus were obtained being relatively free of artifacts induced by movements.In order to produce a caloric reaction in the cat, it was necessary to set the temperature of the irrigating water to, at least, 10°C either below or above the rectal temperature (38°C).Repetitive caloric stimulation with both cold and hot water was conducted under various conditions and the results were described for each. The data suggested the most appropriate way for obtaining reliable results with the caloric test in the cat.

Vascular paramedian pontine lesion associated with vestibulo-ocular disturbances.

Two cases of a peculiar vestibulo-ocular disturbance are reported. Both showed a crossed hemiplegia, that could be ascribed to a vascular paramedian lesion in the right side of the pons.There was a left-beating, horizontal nystagmus of the second degree, which appeared spontaneously or in the head-hanging position; no nystagmus was recorded when the eyes were closed. It partly disappeared after a few weeks and was replaced by a directional preponderance to the same side, which was observed in caloric, rotatory and optokinetic tests; a small dose of a barbiturate (Evipan) elicited a nystagmus resembling the spontaneous nystagmus found in the early stages of the disease.Caloric stimulation of either labyrinth provoked a very slight, if any, nystagmus reaction when the patient's eyes were closed; the same test withthe eyes open resulted in an intense nystagmus. After several months, more normal conditions returned, with a marked caloric nystagmus recordable behind closed eyelids; the nystagmus was now partia...

PER- AND POST-ROTATORY TESTS OF THE VESTIBULAR FUNCTION

Part 1. Findings in Normal Subjects. Two types of rotatory examination, cupulometry and threshold-latency method, were performed and values were obtained with regard to the duration of post-rotatory nystagmus, the latency and the threshold of per-rotatory nystagmus. Nystagmus was observed behind Frenzel's spectacles. Fifty apparently normal test-subjects (among them, seven were ballet-dancers) were examined in this study. Rotatory stimulation was given by means of an electrically driven rotating chamber which is constructed so as to be easily controllable at any needed angular acceleration or deceleration, as well as at any needed angular velocity. Sudden but smooth stoppage of this chamber is possible, too. The results obtained were as follows:- 1) Nomograms predicting the limits of variation of cupulogram were presented. 2) Normal value of the latency of nystagmus was about four seconds (4.3±3.7). 3) The threshold of nystagmus in subjects was found between 0.3∼0.75/sec2. In, cases of ballerinas, the threshold was found within the range, but with a slight elevation of the threshold. These results led us to the conclusion that, when the subjects, are examined who used to receive repeated rotatory stimulation in their daily life, the vestibular reaction is depressed, when expressed with the duration of post-rotatory nystagmus, On the other hand, however, in these cases, no distinct disparity from values can be observed regarding the latency and the threshold of nystagmus. Statistical difference between reactions of the labyrinths on both sides was not remarked regarding the duration, the latency and the threshold. Part 2. Findings in Patients. Vestibular examination was performed on 63 pathological cases (33 cases with peripheral vestbular lesions, 30 with central ones) who visited the ear-nose-and-throat clinic in our hospital with chief complaints of vertigo and disturbances of equilibrium during these two years. The results obtained in these cases led us to the following conclusions: 1) Comparison between per- and post-rotatory examination With regard to the ability to discover either the and/or the abnormality of vesti- bular function, per-rotatory test was found surpassing post-rotatory one. Threshold-test had an ability to indicate the affected side in cases of acoustic tumor and Meniere's disease etc., and, moreover, allowed to determine quantitatively the extent of the vestibular deficit. Latency-test appeared to have the same .characteristics but seemed to be inferior to threshold-test in its ability to indicate the side of the lesion. 2) Comparison between rotatory test and caloric test In more than half the cases, whose threshold of per-rotatory nystagmus was regarded within values, caloric test could reveal pathologycal findings. This must depend upon the fact that, contrary to caloric test, rotatory test stimulates. both labyrinths at a time and also the fact that a compensatory action of the central nervous system participates more easily in the mechanism of nystagmic reaction. Consequently, when one attempts to detect laterality of the periphetral labyrinth, caloric test is regarded to be more usefull and valuable than rotatory one, if applicationof the former is only possible.

A method for direct registration of the speed of the eye-movements in nystagmic reactions.

A method for direct registration of the speed of the eye-movements in nystagmic reactions.

A new technique for vestibular investigation.

In the Barany test and in all the other similar methods of vestibular rotatory stimulation the nystagmic reaction is obtained by a sudden stop of the rotation, at different speeds. According to our knowledge on the cupular mechanism since the experiments of Steinhausen, Dohlman and others, the excitation of the cupula in a rotating movement results from the acceleration or deceleration of the rotation only.

Vestibular Reactivity to Caloric Stimulation in Schizophrenics

Abnormalities in the vestibular reactions in schizophrenics have been reported in the literature. Pekelsky (1921) observed transitory lack of caloric response in two cases of catatonic stupor. Rosenfeld (1926) described four cases of acute catatonia in which on calorization a slow deviation appeared instead of the physiological response. Claude, Baruk and Aubry (1927) examined four cases of catatonia, eight of hebephrenia and one of dementia paranoides. In one of the catatonic cases no caloric or galvanic response could be elicited, and in the three others the reactions were diminished. The other cases showed normal reactions. The authors stated that a diminution of the responses could sometimes be observed in hysteria. Claude, Bourguignon and Baruk (1932) found the Chronaxie of the vestibular nerves greatly increased in patients with catalepsy, but normal after the disappearance of that symptom. Joo and Meduna (1935) stated that in old-standing cases of schizophrenia a lack or a considerable diminution of the vestibular responses could nearly always be found. Sercl and Vinar (1937) examined the vestibular reactivity in twelve cases of hebephrenia and thirteen cases of paranoid schizophrenia. The responses to rotation were normal in all cases. The caloric responses were found to be diminished or lacking. Lack of caloric response was more frequent in the hebephrenic than in the paranoid cases. Löwenbach (1936), working on Gjessing's cases of periodic catatonia, carried out quantitative investigations taking into account the latency period of nystagmus, its duration and the number of oscillations. He examined thirty cases, each of them repeatedly, and attempted to correlate the results of the tests with the periodical changes in the clinical picture. He found that shortly before and during periods of stupor the vestibular reactivity dropped, and that sometimes only a slow deviation could be elicited. The lowering of the frequency was due to the prolongation of the slow phase. The abnormalities were independent of the duration of the illness, and in some old-standing cases the response was normal. Sometimes a temporarily diminished reactivity was noticed which did not coincide with a change in the clinical picture. Löwenbach noted frequent and often abrupt changes in individual cases, and in some he observed transitory complete loss of reaction. Angyal and Blackman (1940) studied vestibular reactivity to caloric and rotatory stimulation in 58 unselected male schizophrenics and in 20 normal controls. The response to caloric stimulation was found to be considerably lowered, the rotatory response only slightly reduced. There was no correlation to the duration of hospitalization or to the conventional subtypes of schizophrenia. However, in a group of five patients with extreme apathy, indifference and poverty of mental contents the reactivity was particularly low. In cases with a periodical course the vestibular reactivity was distinctly lower during the catatonic periods than during the intervals. The same authors (1941) investigated the nystagmic reactions to caloric stimulation under the influence of alcohol, hyperpnoea and CO-inhalation in schizophrenics and normal persons. While in normals alcohol intake results in an increase in the frequency of the nystagmus, in schizophrenics a decrease was observed. CO, which normally has a depressing effect on the nystagmic reaction, produced an increase in schizophrenics. Hyperpnoea, while causing an increase in normals, had the opposite effect in schizophrenics. Freeman and Rodnick (1942) studied the amount of sway induced by rotation in thirty schizophrenics and in an equal number of normal controls. The patients were found to be significantly less reactive than the normal subjects.

INFLUENCE OF VESTIBULAR STIMULATION ON THE FUSION FREQUENCY OF FLICKER: IN NORMAL SUBJECTS AND IN PATIENTS WITH POSTCONCUSSION SYNDROME

Cerebral concussion may produce subjective disturbances for a considerable period without being associated with objective clinical signs. Since dizziness is one of the most frequent complaints, it has been assumed that the vestibular apparatus is frequently affected by concussion. Vertigo as a symptom complaint is subjective. Tests for this condition (Romberg test; deviation test; finger to nose test) depend on the patient's cooperation, and their significance is often easily appreciated by the patient. These tests are difficult to apply in cases of malingering. Because of its objective nature, one of the best tests available is the nystagmus reaction to caloric stimulation. Since the nystagmus reaction may be normal in patients with considerable disturbance, the presence of a pathologic nystagmus response would indicate objective impairment, but a normal nystagmus reaction would not exclude it. The variability of the nystagmus effect may be partly due to the judgment of the observer. Hence,

PARADOXICAL VESTIBULAR REACTIONS IN SCHIZOPHRENIA UNDER THE INFLUENCE OF ALCOHOL, OF HYPERPNEA AND CO2 INHALATION

1. The nystagmic reaction to caloric stimulation under the influence of alcohol, increased CO2 tension and decreased CO2 tension has been studied in schizophrenic and normal persons. 2. Under these experimental conditions, the schizophrenic patients showed an apparently paradoxical reaction. a. Under the influence of alcohol the normals showed an increase, the patients a decrease in the number and frequency of nystagmus. b. CO2 depresses the nystagmic reaction in normals. In 40 per cent of the patients, CO2, causes an increased reaction; 45 per cent show no change and 15 per cent behave somewhat similarly to the normals. c. Hyperpnea causes an increase in the normals and a decrease in the patients.

Labyrinthine Reactions and Their Relation to the Clinical Tests

The rapid tilt test has shown that the vertical semicircular canals are in close connexion with the whole postural body musculature. Nystagmus reactions are only a small part of semicircular canal sphere of control.Further knowledge of the reaction-pattern of the body musculature resulting from the stimulation of each semicircular canal will help in diagnosing a lesion, not only of the individual semicircular canals, but also-even more important-of its intracranial connexions. The few reaction patterns already known, but not recognized as such, namely post-pointing, falling, and head turning, are true compensatory reactions, more easily understood if so considered and grouped with the protective reactions to the tilt tests.Recognition of the two modes of utricular action is essential to a correct analysis of tilt test reactions. The slow tilt described by Grahe and others, is an excellent test for "first mode" utricular action, but not for "second mode" action or for vertical semicircular canals.The quick tilt is primarily a test of vertical semicircular canal action, but normally the reaction is complicated by reactions from "second mode" utricular stimulation. If this fact is not taken into account the analysis of a reaction to a quick tilt may be misleading. When performing a quick tilt test, in addition to watching for the absence of the protective reaction (due to loss of one or both labyrinths), the investigator should try to note whether there is a tendency for the patient to be more easily thrown in the direction of the tilt-owing to a lesion of the vertical canals, the utricles being intact ("second mode" utricular action)-or whether there is a tendency for the patient to over-compensate (owing to a lesion of the utricles, the vertical canals being intact).If, in addition to the usual equilibrial tests, the quick tilt test is used in this way and a careful analysis is made of the reactions of patients with labyrinthine or intracranial lesions, diagnosis of lesions of individual labyrinthine end-organs or of their intracranial connexions may become a routine procedure in the clinic just as it is now possible in the laboratory.

EFFECTS OF DRUGS ON VESTIBULAR REACTIONS

The demand for some drug which will act specifically to reduce the irritability of the vestibular apparatus is great. For a long time general sedatives, such as bromides and opium derivatives, have been employed with some degree of success. The chief objection to these is that when a sufficient amount is prescribed to reduce vertigo, the patient is incapacitated by the general depression. Several years ago Jonkhoff 1 and de Kleyn and Versteegh 2 reported that the vestibular apparatus was decidedly influenced by a number of drugs. This led us 3 to study the effects of drugs on vestibular reactions. The outstanding compounds of each pharmacologic group were used. The nystagmic reaction to rotation was taken as the measure of the degree of stimulation of the vestibular system. As no operations were performed, there was no question of allowances for mutilation. The results were disappointing. There was

Case of Vertigo (simulating “ Ménière's Disease ”) with Anomalous Nystagmus Reactions

Case of Vertigo (simulating “ Ménière's Disease ”) with Anomalous Nystagmus Reactions