Frenzel Glasses Research Articles

Peripheral-vastibular spontaneous nystagmus. Analysis of reproducibility and methoidolgies.

With peripheral spontaneous nystagmus the intensity and its reproducibility was electronystagmorgraphically analyzed with eyes open under Frenzel's glasses and with eyes closed. 1. The maximum intensity of a spontaneous nystagmus with eyes closed is several times higher than under Frenzel's glasses. 2. A weak nystagmus can, under Frenzel's glasses, only be recognized under favorable conditions. A rather long and careful search in a totally dark room is necessary. 3. With purely peripheral lesions, the spontaneous nystagmus with closed eyes shows large intensity fluctuations, and it may disappear temporarily despite mental arithmetics. Contrary to this, with eyes open under Frenzel's glasses, the intensity fluctuation of the nystagmus is remarkably lower. Therefore, even experimental examinations with patients should be carried out electronystagmorgraphically under Frenzel's glasses. The absolute reaction is lower, but the content of information is higher because of the significantly better reproducibility.

A case of left-sided cerebellar-pontine angle gliobla-stoma multiforme with cerebellar gaze nystagmus and an irregular mixed nystagmus

The patient was well until Feburary 1971, four months before admission when, at the age of 22, he noted abruptly the onset of dizziness, headache and diplopia. During the four months before admission, he experienced unsteadiness of gait, left sided sudden deafness, difficulty in swallowing, thick speech, urinary hesitancy, papilledema and a lack of co-ordination. Examination of the cranial nerves showed diminished left sided facial sensation including an absent left corneal reflex, left lateral rectus palsy, left facial palsy, left sided deafness, absent caloric response on the left side, left glossopharyngeal palsy and vagal palsy.At the time of the first surgery June 19, 1971, an egg-sized tumor was extirpated, (left sided cerbellarpontine angle) and the diagnosis of glioblastoma multiforme was made. Treatment with Co60 irradiation was initiated after the surgery, the patient was improving satisfactorily and was discharged on August 28, 1971. Subsequently he has been re-admitted twice.At the time of the second surgery November 2, 1972, atrophy of the left cerebellum was most evident.In the neuro-otological examinations of this patient, Bruns-Cushing type nystagmus was observed on admission June, 1971 and two months later the nystagmus changed to pendular nystagmus on leftward gaze. At the time of second surgery November 2, 1972, gaze nystagmus, like congenital nystagmus, spontaneous horizontal nystagmus to left side, and an irregular-mixed nystagmus in Frenzel glasses were observed. While the gaze nystagmus was thought to be associated with atrophy of the left cerebellum, as there were signs of tremor of eyeballs to the left gaze, spontaneous horizontal nystagmus to the left ceasing with eye closure or, in Frenzel glasses, and cerebellar findings of eye tracking and optokinetic tests, an irregullar-mixed nystagmus was probably mainly related to vestibular nuclei occurring with eyes closed or, in Frenzel glasses and from the clinical appearance. This vertical nystagmus was also thought to be related to lesions of cerebellar vermis, as the nystagmus was influenced by changes in the position of the head.

Zur kalorischen Erregbarkeitspr�fung: Kulminationsphase und Fehlerbreite bei verschiedenen Beobachtungsintervallen

120 caloric vestibular tests (50 ml water of 30° resp. 44° in 30 s) were carried out on 30 normal persons 20—30 years of age. The responses were analyzed as to the reliability of evaluation using Frenzel's glasses, in case of a limited evaluation to a defined observation period. This observation period was located at different time-intervals after stimulation and compared to the maximal phase of reaction registered by ENG simultaneously.

Suppression of congenital nystagmus.

Suppression of congenital nystagmus by eyelid closure was studied by electrooculography in four cases under various conditions in order to elucidate whether the suppression is caused by blocking of fixation or not. The nystagmus persisted in the light as well as in the dark provided that the eyes were kept open. Frenzel's glasses did not suppress the nystagmus except for one case in whom jerky nystagmus was attenuated. In the other cases, only voluntary lid closure suppressed the nystagmus. Passive lid closure while the patient attempted to keep eyes open did not suppress the nystagmus except in one case. Reflex eyelid closure by glabellar tap did not suppress the nystagmus in spite of the occurrence of Bell's phenomenon. Passive eyelid opening while the patient attempted to keep eyes closed, on the other hand, did not reproduce the nystagmus. The suppression of congenital nystagmus by lid closure, at least in some cases, seems to be related to the voluntary effort to keep eyes closed but not specifically to blocking of fixation.

Equilibrium disturbances in patients with unilateral and bilateral loss of labyrinthine excitability

Long-term observations on equilibrium disturbances in patients with unilateral and bilateral loss of labyrinthine excitability were undertaken. The purpose of the study was to elucidate the peculiarity of equilibrium disturbances when the compensatory adjustments are inefficient and clarify how the labyrinthine reflexes function in the daily behavior of humans.The study included 6 patients with unilateral loss of labyrinthine excitability and 5 with bilateral loss of labyrinthine excitability.Questioning and equilibrium related examinations were performed at regular intervals for periods of more than 5 years after the incidence of the loss of labyrinthine excitability.Equilibrium disturbances continuing more than 5 years were as follows : (1) Those with unilateral loss of labyrinthine excitabilityOn questioning, the patients complained of disturbances of body balance in standing and walking in the dark. On the standing test, the patients could not maintain Mann's and one-leg standing. Writing and stepping deviation were not remarkable. Spontaneous nystagmus under the Frenzel's glasses continued. The optokinetic nystagmus was normal.(2) Those with bilateral loss of labyrinthine excitabilityOn questioning, the patients complained of disturbances in visual fixation while walking and running (jumbling phenomenon) and disturbances of standing and walking in the dark. The standing test with eyes open was within normal limits but that with eyes closed indicated moderate to marked disturbances of righting function. Staggering gait was observed in the stepping test. The optokinetic nystagmus was normal, showing visual fixation when the stationary position was not disturbed.The results indicate that the vestibulo-ocular reflexes in humans play an active part in visual fixation during movements with periodic head motion such as walking and running and that the most important role of the vestibulo-spinal reflexes is the righting reflexes which aid in maintaining standing posture.

1. Effect of Different Conditions of Ocular Fixation

Twelve normal subjects received standard caloric testing under the following conditions: 1) fixation, 2) Frenzel glasses in a dimly lit room, 3) eyes open in total darkness, and 4) eyes closed. Multiple nystagmus response parameters were evaluated and statistically compared for each condition. Fixation markedly diminished induced nystagmus and produced the largest coefficient of variation for each response parameter. Caloric testing with eyes closed resulted in periodic nystagmus suppression and a less distinct saw-toothed pattern. As with fixation, the coefficient of variation was consistently higher with eyes closed compared to eyes open in darkness or Frenzel glasses. It is concluded that caloric testing of the vestibulo-ocular reflex arc should be performed with eyes open in darkness or with Frenzel glasses.

Caloric test with oculogyral illusion as response

It has been demonstrated that the caloric test can be simplified further by making use of the oculogyral illusion. Since the test is conducted under conditions of optic fixation, this method probably also enhances the sensitivity of the caloric test. The reproducibility of the tests also appears high, at least in respect of measures of "canal paresis". When used in conjunction with other tests for detecting vestibular imbalance, e.g. examination for spontaneous and provocation nystagmus using Frenzel glasses, this OGI caloric test should provide a convenient procedure for the clinical examination of vestibular function.

Spontaneous and positional nystagmus in healthy persons demonstrated only by electronystagmography: Physiological spontaneous nystagmus or ?functional scar??

We wanted to ascertain whether a physiological horizontal vestibular spontaneous nystagmus is existent, or whether the spontaneous and positional nystagmus seen in clinically healthy persons in the electronystagmogram -- when fixation had been excluded completely -- was always the result of earlier damages to the vestibular system (Jatho). For this purpose we tried to detect a spontaneous and positional nystagmus in 102 healthy persons from 6 age groups (17 each) between 11 and 70 years of age. When the ENG was registered with open eyes in darkness, 63 out of the 102 test persons had a horizontal spontaneous or positional nystagmus, however, under the Frenzel glasses there was a nystagmus in only 2 out of these test persons. With open eyes in darkness, the frequency and intensity was the same in all age groups. With this, we believe to have proved that a physiological horizontal vestibular nystagmus does exist. We share Kornhuber's opinion that the examination with the Frenzel glasses in a dark room, together with the head shaking test and positional test, at the present time represents the best method for differentiating between physiological and pathological spontaneous nystagmus.

Zur diagnostischen Wertigkeit des nur im Elektronystagmogramm nachweisbaren Lagenystagmus

In an earlier investigation (Mulch and Trincker, 1975) it was established that 50% of 120 carefully selected young healthy persons normally showed, when completely excluding any fixation, a slightly intensive vestibular spontaneous nystagmus in at least one position. In a recent series of investigations we now examined 102 test persons from 6 age groups (17 persons per group) between 11 and 70 years of age with the aid of the ENG. Subjectively, these test persons were without complaints. However, contrary to our earlier group of test persons, we did not eliminate those patients with a case history including diseases likely to lead to vestibular damage (e.g. cocussion, otitis). With these investigations we were in the position to prove that the spontaneous nystagmus described in our earlier paper can occur at any age and with the same frequency. Thus, we could exclude that it is the consecutive symptom of an earlier, perhaps traumatic injury (Jatho). If we detected spontaneous nystagmus, its average intensity (speed of the slow phase, total amplitude/min, beats/min) when registered with open eyes in darkness was the same in all age groups. In addition, the present group of test persons was compared with the recent one. These Findings as well as others, which still have to be described, confirm our hypothesis that the here detected spontaneous nystagmus, which is not visible with the Frenzel glasses, is a physiological incident. These findings will have to be considered particularly when giving an opinion on patients with suspected vestibular diseases.

The Effect of Eye Closure Upon the Pathological Vestibular Spontaneous Nystagmus

In the course of one year (September 1973 to September 1974) a total of 784 patients were examined with nystagmography. We were dealing with patients who consulted us for reasons of equilibrium disturbances, sensori-neural hearing loss and/or tinnitus. In 200 patients we observed a definite vestibular spontaneous nystagmus (SN) in supine position. Ocular pendular nystagmus was eliminated. On the basis of these 200 electronystagmographic recordings, the effect of eye closure upon the pathological spontaneous nystagmus was analysed. According to the statistical mean value, spontaneous nystagmus with open eyes in darkness was stimulated by eye closure. Further evaluation revealed, however, that 24% of our patients showed spontaneous nystagmus exclusively with open eyes in darkness, 30% only with closed eyes. Nevertheless, the occurrence of spontaneous nystagmus with either open or closed eyes in darkness, or in both conditions, does not permit topodiagnostic conclusions. The possibility of nystagmus inhibition by eye closure must be considered when the case history indicates a vestibular disturbance but a spontaneous nystagmus with closed eyes is absent in the electronystagmography. The clinical observations in one patient are described in detail for example. To exclude errors, one should search for a spontaneous nystagmus following the necessary examination behind Frenzel's glasses—in case of nystagmography—by closed as well as by opened eyes in darkness.

Note on the value of Frenzel's glasses for the recognition and qualitative evaluation of spontaneous nystagmus.

Spontaneous nystagmus encountered in neuro-otological practice is nearly always a physical sign of high diagnostic importance. Its localizing value is largely determined by certain of its qualitative characteristics and these are best studied and evaluated by means of the electronystagmograph, but for reasons discussed this is not suitable for use in smaller clinics. For the recognition and qualitative analysis of spontaneous nystagmus the use of Frenzel's glasses used in complete darkness, as recommended by Frenzel himself, has been found to give very satisfactory results.

Effects of temporary occlusion of a vertebral artery on the human vestibular system.

✓ Vestibular responses elicited by temporary occlusion of one vertebral artery were observed in 25 cases of intermittent vertebral artery compression (Power's syndrome) during surgical treatment by periarterial denervation of an isolated vertebral artery. This produced manifold varieties of spontaneous nystagmus, ocular movements without noticeable pupillary changes; the ocular manifestations included coarse vertical nystagmus, monocular horizontal nystagmus, convergence nystagmus, and conjugate or disconjugate eye movements. Subjective symptoms were observed in only approximately one half of the cases. These results support the concept that the vestibular nuclei as well as the oculomotor system in the brain stem are particularly sensitive to reduced blood flow through the vertebrobasilar arterial system. Examination of nystagmus under Frenzel glasses proved to be one of the most sensitive tests in evaluating the circulatory status of the brain stem.

Electronystagmography in daily ENT practice. The use of electronystagmography in the posture test.

THE AIM of this paper is to demonstrate the importance of electronystagmography (ENG) in routine ear, nose, and throat practice. In the retina, electric processes are always taking place, even in the dark, causing the retina to be charged negatively against the cornea. Hence the eye is considered a dipole, the electrical axis of which coincides with the optical axis. Any movement of the eyes changes the field power in the region near the eyes. With ENG the eye movements are recorded via these changes in the field power (Fig 1). The existence of the corneoretinal potential difference has been described by Emil Dubois-Reymond1 in 1849. A great advantage of recording eye movements with ENG above direct observation of eye movements by the naked eye, with or without the Frenzel's glasses, is the fact that eye movements are recorded with the apparatus which cannot be discerned by direct observation. Jongkees