[A comparative study of electronystagmography and photo-electronystagmography].
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Electronystagmography↗
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[Indications for electronystagmography. When should the ENT physician indicate electronystagmography?].
With the increasing application of technology in medicine, clinical vestibular examination using Frenzel's spectacles is often thought to be out of date, and an electronystagmogram (ENG) is ordered. However, some important facets of the clinical behaviour cannot be determined by ENG alone, especially nystagmus after head-shaking, and the rotatory nystagmus of paroxysmal positional vertigo. Thus, in most cases routine vestibular examination is sufficient, and ENG is only indicated in certain cases. The ENG is then of considerable advantage for determining qualitative characteristics and for quantitative analysis of the nystagmus. The various methods of stimulation and of recording, the limitations and the advantages of the ENG are described in detail. An examiner fully familiar with the advantages and disadvantages of the various methods will profit from the use of ENG. However, the classical examination, including a thorough vertigo analysis, remains indispensable.
Electronystagmography↗
Electronystagmography in daily ENT practice. The use of electronystagmography in the posture test.
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Arteriosclerosis↗
A comparison of electronystagmography results with posturography findings from the BalanceTrak 500.
OBJECTIVE: To determine a correlation between conventional electronystagmography findings with results obtained from BalanceTrak 500 posturography assessment. STUDY DESIGN: Individuals with a variety of dizziness and balance disorder symptoms were tested with both electronystagmography (ocular motor studies, positional/positioning testing, caloric testing) and computer posturography using the BalanceTrak 500. SETTING: Tertiary referral center. PATIENTS: Urban/rural midwesterners referred for dizziness and balance dysfunction symptoms. INTERVENTION: Results of both testing modalities were sent to referring physicians. OUTCOME MEASURES: Electronystagmography and posturography results. RESULTS: When electronystagmography results were compared with BalanceTrak findings, a majority of patients whose electronystagmography findings indicated central and mixed causes, or peripheral lesions other than benign paroxysmal positional vertigo, had abnormal findings on posturography. Specifically, tests similar to the Balance Master Sensory Organization Tests 4 and 5 and a new test, Limits of Stability, presented the most difficulty for these individuals. Patients with normal electronystagmography findings and those with benign paroxysmal positional vertigo had mixed results on posturography. The results for specific individual electronystagmography tests were compared with those of posturography tests. No correlation was noted among any of the electronystagmography results and posturography findings. Furthermore, no correlation was observed between posturography and the causes of dizziness. CONCLUSION: For many patients with dizziness and/or balance dysfunctions, posturography can provide additional information to that obtained with electronystagmography. This is especially apparent in individuals who have these symptoms but have normal or borderline normal electronystagmography findings.
Dizziness↗
Electronystagmography finding in children with peripheral and central vestibular disorders.
OBJECTIVE: Dizziness and imbalance are uncommon in children, but often alarming for their families: a detailed interview and otoneurological examination are important for reaching a specific diagnosis and treatment. Children with vestibular disorders are thought to be difficult to examine: vestibular tests (caloric test, roto-acceleratory test, electronystagmography, opto-kinetic nystagmus, cranio-corpography and posturography) are used less frequently for children than in adult patients. The aim of the study was to determine whether the results of electronystagmography testing improve an emergency physician's diagnosis of dizziness in children. METHODS: Patients were selected on the basis of the following inclusion criteria: aged between 2 and 12 years and affected with vertiginous symptoms. All patients underwent the following instrumental examinations: blood tests, audiological screening, electronystagmography of spontaneous nystagmus or provoked by vestibular and optical stimulation and electroencephalogram. RESULTS: The results underlines an high incidence of central vertigo (83%): 52% of the children presented a prevailing unidirectional nystagmus at labyrinth stimulation and 48% of the children an asymmetry in the response of nystagmus at optical kinetic stimulation with quality alteration of shocks. CONCLUSIONS: Electronystagmography can register and evaluate the qualitative and quantitative characteristics of the nystagmic response and allow to distinguish between central or peripheric vertigo: different degrees and various combinations of the abnormal responses shown in optokinetic central test were the most characteristic of electronystagmography in patients with vestibular central vertigo.
Cerebral Cortex↗
[What is the role of contact lenses within the scope of electronystagmography?].
BACKGROUND: During electronystagmography it is necessary to correct detective vision for calibration, smooth pursuit, and saccadic eye movements. Therefore more and more people use contact lenses instead of normal glasses. Given the lack of detailed information about this phenomenon, in the current literature we decided to investigate the influence of soft contact lenses on electronystagmography. The aim of this study was to find out differences in the results of electronystagmography between using glasses or contact lenses. METHODS: Our investigation involved 20 vestibular healthy human subjects with myopia. In the first part of the examination they used their contact lenses and in the second part they were wearing normal glasses. After measuring the calibration potential we wanted to see if contact lenses would increase the rate of artifacts in the electronystagmogram. Then we attempted to determine whether contact lenses would an influence on the registration of the optokinetic nystagmus. Induced saccadic eye movements were recorded and analysed. RESULTS: Contact lenses had a negative influence neither on the calibration potential nor on the rate of artifacts. The latency of the saccadic eye movements also showed no differences between both parts of this investigation. Only the velocity of the saccades and the gain value during the optokinetic test were reduced when glasses were used. CONCLUSIONS: Contact lenses may stimulate the secretory function of the lacrimal gland and thus decrease friction forces. It is also possible that the reduced image size produced or the reduction-effect of minus by glasses in near sighted persons negatively influences eyeball velocity. In summary, our study demonstrates that contact lenses do not have a negative influence on electronystagmography. Therefore electronystagmographic studies of patients with contact lenses are permissible for purposes of documenting a medical opinion.
Adult↗
Modern electronystagmography for vestibulometry practice.
The following problems of the practical use of electronystagmography (ENG) are examined in the article: direct and indirect ENG recording, types of amplifiers, determination of the time constant of the amplifier of the recording instrument, specific significance of the values of the time constant and amplification for the information content of the nystagmus indices, limits of the linear relation between eye movements and their recording on an instrument with a different amplification and time constant, calibration of eye movements and calibration of the instrument, effect of light on the value of the corneo-retinal potential, value of the angle of calibration of eye movements with fixation of the gaze in the middle position or only at the extreme points of the central angle, paper speed when recording nystagmus, and type of recorder pen. On the basis of an analysis of 4325 EOG and ENG new principles were established and appropriate recommendations were made for improving the quality and effectiveness of electronystagmography. With consideration of the established new facts the recommended technique of modern electronystagmography is presented.
Amplifiers, Electronic↗
Abnormal electronystagmography in rheumatoid arthritis.
OBJECTIVE: Although sensorineural hearing loss has been widely investigated in those with rheumatoid arthritis, studies assessing the vestibular system in patients with rheumatoid arthritis are limited. The aim of this study was to assess the vestibular system in patients with rheumatoid arthritis. METHODS: The study consisted of 43 patients with rheumatoid arthritis and 30 healthy controls. Otorhinolaryngologic and neurotologic examinations, pure-tone audiometry, impedancemetry, electronystagmography including smooth pursuit, saccade, positional, and caloric tests were performed in all patients with rheumatoid arthritis and in controls. The erythrocyte sedimentation rate, C-reactive protein level, and rheumatoid factor level were evaluated in all patients with rheumatoid arthritis. RESULTS: Audiograms revealed sensorineural hearing loss in 12 patients (27.9%) with rheumatoid arthritis and in two controls (6.6%); the difference was statistically significant (P=.033). In those with rheumatoid arthritis, the results of electronystagmography revealed central abnormalities in nine patients (20.9%), peripheral abnormalities in three (6.9%), and mixed abnormalities in three (6.9%). Smooth pursuit and saccade tracing impairments were significantly higher in patients with rheumatoid arthritis (P>.05). Canal paresis in patients with rheumatoid arthritis were significantly higher than those in the control group (P=.039). No association was found between electronystagmographic abnormalities in patients with rheumatoid arthritis and age, sex, duration of disease, the results of laboratory testing, sensorineural hearing loss, or medication use. CONCLUSION: Our results suggest an association of rheumatoid arthritis with vestibular system dysfunction as well as auditory impairment.
Acoustic Impedance Tests↗
[Evaluation of patients with dizziness and normal electronystagmography using stabilometry].
UNLABELLED: The causes of dizziness are difficult to be diagnosed. At present we have a variety of tests and exams but none of them can adequately evaluate the vestibular function. The most commonly used tests are electronystagmography and posturography. AIM: The objective of this study was to analyze the results of stabilometry in patients with complaints of dizziness who had normal results in electronystagmography and to compare them with a control group. STUDY DESIGN: The study was prospective, sectional transverse. MATERIAL AND METHOD: It was conducted at the ENT department of the University Hospital in Rio de Janeiro's Federal University. Twenty-two patients (fifteen women and seven men) were evaluated with ages, on average, of 47.6+/-9. The control group was made up of twenty-five healthy individuals (eighteen women and seven men) with ages, on average 46.8+/-7. RESULTS: In all analyzed parameters, there were statistically significant differences between the groups. Comparing the results with eyes closed and opened, the antero-posterior medium velocity, in control group, was the only statistically significant result. CONCLUSION: We concluded that the group of patients had results statistically significant in relation to the control group in all the analyzed parameters, showing that the group of patients with complaints of dizziness had more instability in standing position than the group of healthy individuals.
Dizziness↗
Electronystagmography: how helpful is it?
Two hundred and sixty patients tested with electronystagmography (ENG) for evaluation of complaints of disequilibrium were the representative sample for this study. As all new dizzy patients currently receive an ENG, the goal of this project was to determine how much an ENG adds to the diagnostic acumen, and which patients really needed an ENG in order to maximize efficiency and minimize patient cost. Results indicate the suspected diagnosis prior to ENG is assisted by its use only when the cause is thought to be central or is uncertain. The percentage of unknown causes of disequilibrium decreased from 34.2 to 13.8 per cent and the percentage of central causes increased from 13.1 to 23.1 per cent. Electronystagmography does not significantly aid in the diagnosis of peripheral lesions except as confirmation. Specific findings and recommendations are discussed.
Adolescent↗
[The problems of electronystagmography in the clinical diagnosis of vestibular diseases (author's transl)].
The aim of a documentation in electronystagmography, that is to record as complete and definite as possible the information of a nystagmus relative to all its distinctive marks, hitherto has been reached just as little as the attempt, to develop a fine-quantitative investigatory method suitable for standardization for medical practice. The sources of error caused by the equipment and of physiological nature within a recorded nystagmus trace are exposed and illustrated by respective examples. Outgoing from the theory of the rotatory nystagmus based on the rotation test of the human vestibular system the fundamentels are developed for a complete evaluation method of an electronystagmogram including the elimination of artefacts by the authors' own research work in this field. However the pointed out problems of the electronystagmography are not yet answered in the clinical diagnostic of vestibular diseases, the systematic examination of spontaneous nystagmus and provoked nystagmus still represents the most important, most profitable and well-grounded part of the vestibular investigation in the medical practice.
Diagnostic Errors↗
A comparison of duration of nystagmus as measured by the Southern California Postrotary Nystagmus Test and electronystagmography.
The Southern California Postrotary Nystagmus Test (SCPNT) and electronystagmography are methods used to evaluate one aspect of vestibular function. The SCPNT is based on the examiner's observation of eye movements and is used in combination with other information as part of a diagnostic battery for children with learning disorders. Electronystagmography is the permanent recording of eye movements through the use of surface electrodes. In this study. The SCPNT and an electronystagmograph were used to record postrotary nystagmus in 20 normal females aged 25 to 30. A significant correlation was found between the two tests for both duration and excursion. In addition, scores of both tests were compared for four normal and for four learning-disabled girls aged 7 to 8. The only significant correlation found was in terms of duration in the normal girls. Results were discussed in terms of factors affecting observation of eye movement, and differences between the nystagmus response of adults and children.
Adult↗
[Diagnosis of Arnold-Chiari malformation by electronystagmography].
3 patients with Arnold-Chiari malformation with vertigo as the sole clinical presentation are described. 2 of them had been undiagnosed for many years despite repeated examinations, including CT scans. The third patient was diagnosed 2 weeks following the initial vertiginous attack. Downbeating nystagmus demonstrated by electronystagmography, indicating a pathological lesion at the craniocervical junction, was the key finding that led to the diagnoses. Following this finding, CT scan directed to the craniocervical junction showed the typical image of Arnold-Chiari malformation. The cases presented emphasize the important contribution of electronystagmography in the evaluation of vertigo due to intracranial lesions. However, computerized imaging examination remains the main diagnostic tool for intracranial pathologic processes.
Adult↗
Frequency responses of office electronystagmography machines.
The high and low frequency characteristics of clinically used electronystagmography (ENG) machines were evaluated using a "dummy patient" calibration source. About one half of the machines yielded tracings that were either seriously divergent from specifications or that otherwise inaccurately reproduced the calibration wave form. Some of these differences do affect the accuracy and quality of clinical recordings.
Electronystagmography↗
Corneoretinal potential variations: significance in electronystagmography.
Spontaneous variations in the corneoretinal potential (CRP) may introduce large errors when using electronystagmography (ENG) to measure responses during clinical caloric testing. Whether or not conventional calibration techniques are adequate to control such measurement errors has not been established. We studied CRP variations in normal subjects and patients by measuring calibration before and after a series of caloric tests. Among patients the CRP either rose or fell in a random manner; we were unable to discover independent measures that might serve to predict the magnitude or polarity of the CRP changes. Among normal subjects the CRP consistently dropped during each caloric test, probably due to longer periods of eye closure imposed in this group. Recalibration before each caloric test, using an averaging technique, would greatly reduce (but not eliminate) ENG measurement errors.
Action Potentials↗
[Data processing in electronystagmography (author's transl)].
As a method for objective registration of nystagmic responses electronystagmography gives a lot of information about the state of the vestibulo-oculomotor system. Concerning accuracy, reproducibilityand objectivity the commonly used methods for diagnostic interpretation of this material are not quite satisfying. By means of a data acquistion system it is possible to utilize the advantages of the techniques of data processing. In common with fundamental considerations regarding to the choice of the parameters to evaluate the essential parts of the computer-program (calibrations, elimination of interferences, analysis of the fast and slow nystagmic components) are described and examples for the results are shown.
Computers↗
Rotational chair (ROTO) instead of electronystagmography (ENG) as the primary vestibular test.
OBJECTIVES: To compare the sensitivity of rotational chair (ROTO) versus electronystagmography (ENG) in peripheral vestibular pathology. METHODS: Retrospective chart review. RESULTS: One thousand consecutive patients undergoing evaluation for dizziness and imbalance at a tertiary care referral balance center were reviewed. ROTO was the primary vestibular study used in all patients with ENG used as a confirmatory test at the discretion of the treating physician. A subgroup of 478 patients underwent both ROTO and ENG. Among the patients diagnosed with peripheral vestibulopathy, sensitivity for peripheral vestibulopathy was 71% for ROTO and 31% for ENG. However, specificity was 54% for ROTO and 86% for ENG. CONCLUSIONS: We conclude that in this retrospective cohort with the authors' clinical diagnoses, ROTO is a more sensitive diagnostic study of peripheral vestibular pathology. The higher sensitivity of ROTO and the higher specificity of ENG may support the use of ROTO as the primary vestibular study and ENG as a supplemental vestibular study. Prospective analysis with distinct diagnostic criteria and defined inclusion criteria are necessary before these results can be widely extrapolated.
Caloric Tests↗
Electronystagmography findings in child unilateral sensorineural hearing loss of probable viral origin.
We studied the labyrinthine function in a group of 72 children aged between 4 and 14 years affected by unilateral sensorineural hearing loss of probable viral origin. From the analysis of the results obtained we confirm the concomitance of cochlear and vestibular damage. However, there were no statistically significant differences between type of audiogram at onset of hearing loss and type of electronystagmography (ENG), while we found a direct correlation between the presence of vertigo or dizziness and type of ENG. Finally hearing recovery was influenced by the presence of vertigo or labyrinthine function alterations. The results of statistical analysis confirmed a significant statistical difference between patients with vertigo or dizziness (V(+)) and those without vertigo (V(-)) and also between patients with ENG 3 (subjects with spontaneous nystagmus or positional nystagmus and canal paresis ipsilateral to the cochlear lesion) and those with ENG 1 (subjects without spontaneous nystagmus or positional nystagmus and with normal vestibular reflex). In fact, hearing recovery was worse in V(+) group and in ENG 3 group.
Adolescent↗