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PubMed1990

Oculographic analysis of acute esotropia secondary to a thalamic hemorrhage.

We used electrooculography to study the saccadic velocities, smooth pursuit, and vestibular ocular reflex in a patient with an acute thalamic hemorrhage. Our findings confirmed what others have shown in that there were hypometric saccades contralateral to the lesion, impaired smooth pursuit ipsilaterally, and a preserved vestibular ocular reflex. In addition, we demonstrated an asymmetry with the contralateral eye being more affected. It is also shown that the "convergence" movements seen on attempted upgaze are typical of saccades and not vergence movements. A discussion of possible pathophysiologic mechanisms with review of other studies is presented.

Aged↗
PubMedDate not supplied

[Characteristics of motion sickness during prolonged otolith stimulation in anti-orthostatic position].

Thirty healthy volunteers were tested for an extended period of time (up to 4 hours) on modified parallel swings during a head-down tilt (-8 degrees) study. The pattern of motion sickness that developed in this situation was evaluated in terms of physiological parameters (electrocardiography, rheoencephalography, arterial pressure, respiration rate electrooculography, etc.), hormonal status, fluid-electrolyte balance, sensory function. The test subjects developed a vestibulo-hemodynamic syndrome that included vestibular disorders, spatial illusions, fluid displacement in the cranial direction, excitation of the hypothalamic-pituitary-adrenal system, changes in fluid-electrolyte balance. The resulting data may help better understand mechanisms underlying motion sickness.

Electrocardiography↗
PubMed1990

[Usefulness and limitation of clinical electroencephalography: from the clinical standpoint].

An electroencephalogram (EEG), is a visible record of the amplified electrical activity generated by the nerve cells of the brain. EEG has produced an abundance of useful information, though it shows only the activity of the immediately underlying cortex. From the beginning in the areas of convulsive disorder and tumor localization, electroencephalography has expanded to become useful not only in many organic brain disorders but also in many extracerebral conditions influencing the central nervous system (ie, metabolic, endocrine, and toxic). It has also shown some usefulness in sleep disorders. Sleep studies on humans are usually performed by using a polygraph to record three types of data: the EEG, the electrooculography (EOG), and the electromyogram (EMG). The EEG is the core measurement of polysomnography. Polysomnography is generally performed in diagnosing a variety of sleep disorders. Other measures used in polysomnography include: 1) Anterior tibialis EMG, 2) Nasal and oral flow, 3) Blood oxygen saturation, 4) Chest and abdominal movement, and 5) Electrocardiogram (EKG). Also different electronic apparatus and equipment for simultaneous and long-lasting observation and recording of varied physiological phenomena and behavioral manifestations (ie, video-electroencephalography with telemetry, topography, power spectrum) were used. However unless electroencephalography is organized and related to medicine and biology much of it will be disregarded and forgotten.

Brain↗
PubMedDate not supplied

[Dynamic functional and electrophysiological indices in patients with complicated high myopia after revascularizing operations].

Vision acuity and differential photosensitivity were examined, and electroretinography and electrooculography data analyzed in patients with high myopia after crossing the superficial temporal artery. A tendency to normalization of these parameters has been observed after surgery, due to improvement of the circulation in the orbital artery basin, as evidenced by ultrasonic dopplerography. The method of automated statistical perimetry was found valuable for predicting the functional results of surgery and for objective assessment of visual functions postoperation.

Adolescent↗
PubMedDate not supplied

[Saccadic automatism in babies during rapid sleep].

Characteristics of rapid eye movements (saccades) in babies (six babies of 1-8 months age) recorded by electrooculography method in paradoxical phase of sleep are analyzed in comparison with analogous data in adults during sleep and in alertness in various conditions of eye movements recording. Coincidence of distribution curves of intersaccadic intervals and amplitudes of saccades in babies and adults is revealed. It is also found that the most frequently met intervals (in the range up to 1 s) in sleep and wakefulness are of comparable values 71.5-90.5%. On the basis of the obtained data the suggestion is made about automation of saccades, forming the base of saccadic activity and manifested in babies and adults during sleep and also in wakefulness, against the background of which other kinds of oculomotor activity are realized. Automation of saccades is formed in early ontogenesis.

Adult↗
PubMed1987

Selection of electrophysiological tests in patients with suspected multiple sclerosis.

If we accept the criteria set by McDonald and Halliday and by the Boston University WorkShop that one of the two lesions in patients with multiple sclerosis may be determined by electrophysiological tests and if we recognize that medical economics sets a limit to indiscriminate use of tests for clinical purposes, we need to pay particular attention to the selection of diagnostic tests. If we accept that certain anatomical predilections of plaques at the onset of multiple sclerosis correlate to a limited extent with long-term prognosis as suggested by Kurtzke, Rosati and Visscher, particularly with the relation to the disability and mortality, we need to pay more attention to the discovery of symptoms and signs as soon as possible utilizing clinical and laboratory data. As of now, the frequency of symptoms and signs at the onset of multiple sclerosis, with minor variations, seem to indicate that motor signs (pyramidal and cerebellar) head the list. Electrophysiological tests are specific for certain anatomical systems. The sensitivity of each test varies, but in most series electrooculography and electronystagmography offer the greater sensitivity. This is because of the significant interconnections between the pyramidal, cerebellar, vestibular and the oculomotor systems. This report underlines the importance of these two electrophysiological tests for the diagnosis of suspected multiple sclerosis.

Cerebellum↗
PubMed1987

Quantitative measurement of upper eyelid movements.

A simple and noncontact method for recording upper eyelid movement by means of a solid state image sensor has been developed. Physiological parameters of blink and lid movements during gaze change were studied in 30 normal subjects. Maximum velocity against lid displacement was analyzed. Electromyography (EMG) of the levator palpebrae as well as orbicularis oculi muscles was conducted and vertical eye movement was recorded by electrooculography (EOG). The maximum lid velocity both for upward and downward gaze change was measured; it was always faster in the downward than in the upward gaze. The duration of lid movement during upward gaze change was about 70 msec longer than that of the vertical saccadic eye movement. By EMG, a pulse-step discharge has been well known to occur in the superior rectus muscle but it was never seen in the levator palpebrae muscle in the present observation. The maximum lid velocity of downward spontaneous blink showed two-phase distributions: phase 1 with an initial flat phase in small displacement and phase 2 with a steep phase in large displacement. By EMG, only the pretarsal portion of the orbicularis muscle discharged at the initial phase; preseptal as well as pretarsal orbicular muscle discharges were noted in the second phase. The simplicity of this technique would permit its wide clinical application.

Adult↗
PubMed1986

The nature of reverse phase reflex eye movement.

The unusual phenomenon of reverse phase reflex eye movement was first described by Ishikawa. In this study the reflex frequency response was examined by electrooculography. In typical cases a reflex was observed by repeated forced duction up to 9 Hz. As a result it was postulated that proprioception is usually involved in reverse phase reflex eye movement, because visual eye movement cannot respond to a movement beyond 1 Hz. When the lag-times between the peaks of forced duction in one eye and those of the reflex movement in the other were measured, they were almost zero or even negative at high frequencies of forced duction as 6 and 9 Hz. This phase advance of the reflex movement was explained only when the receptor of the reflex had a dynamic response, because 90 degrees phase advance results in a reflex through such a receptor. The primary ending of muscle spindle represents such a receptor. The magician's forceps phenomenon as first discovered by Mitsui in exotropia is supposed to be a blocking reflex through the tendon organ. The transmission lag-times of both reflexes can be as short as 20 msec, but must be slightly longer to consider them to be monosynaptic.

Adolescent↗
PubMed1979

Smooth-pursuit eye movements in the newborn infant.

The capacity of newborn infants to smooth-pursuit eye movements in single-target tracking and in optokinetic nystagmus to a moving striped field was examined utilizing DC electrooculography. Smooth-pursuit movements were observed in all infants who were alert during testing, but they occupied less than 15% of viewing time during single-target tracking. The velocity of smooth-pursuit segments in single-target tracking increased linearly to a target velocity of 19 degrees/sec and deteriorated rapidly at faster speeds. No smooth pursuit occurred above 32 degrees/sec in single-target tracking. By contrast, optokinetic nystagmus was observed at all field velocities to 40 degrees/sec, but the speed of the mean slow component increased linearly to 25 degrees/sec and diminished above that field velocity. Infant optokinetic nystagmus differed strikingly from that of adults in that tonic ocular deviation was in the direction of field movement rather than away from it. This feature of neonatal optokinetic nystagmus is consistent with deficient foveal function and suggests that the relatively poor smooth-pursuit performance of newborns may be related to foveal immaturity.

Electrooculography↗
PubMed1978

[Electrooculographic examination in paralytic and concomitant squint (author's transl)].

There are shown some possibilities of electrooculographic diagnostics in different forms of strabismus. Kinetic disturbances in fusion in concomitant squint are usually frequent but not constant and in the majority they are different from incomitances in paralytic squint. In this mind electrooculography represents subtile and perspective method in examination of ocular motility.

Child↗
PubMed1984

[A biological rhythm in a patient with normal pressure hydrocephalus--comparative studies in pre- and postoperative patients by a polygraphy].

The authors had studies the correlation between the appearance of the pressure waves and the level of the sleep in pre- and postoperative patients with normal pressure hydrocephalus (NPH). The changes from preoperative findings to postoperative ones were discussed in detail with the relation of the pathophysiological state in these patients. Seventeen patients were evaluated for the suspected diagnosis of the disease of NPH. Thirteen patients of them were treated with ventriculo-peritoneal shunts. Four representative cases among them were evaluated by pre- and postoperative polygraphic studies. A polygraphic overnight study includes a monitoring of an intracranial pressure (ICP), electroencephalography (EEG), electrooculography (EOG), respiratory movement and electromyography (EMG). Each data was recorded for the analysis on data recorder using a computer system. A pressure waves (largely B type) appeared accompanied with an apnea at a resting state (so-called sleep) of each patients. An arousal response in EEG was also observed in the raising period of the pressure waves. At the peak respiration was resumed with transient activities in EMG and continued to the disappearance of the pressure wave. Pressure waves were observed frequently and continually in hours in the resting state of these patients. As a result the level of sleep alternated frequently between an awake stage and a stage 1, including extremely rare appearance of stage 2. In short, the level of sleep was frequently interrupted by the appearance of the pressure waves and apneas. Such pathological states of patient's sleep were involved in the entity of the sleep apnea syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Downbeat nystagmus during eye closure].

We studied eye movements and clinical findings in 1225 patients with complaints of dizziness. Downbeat nystagmus was demonstrated in 11 patients during eye closure. Simultaneous vertical and horizontal eye recordings were examined to demonstrate vertical eye position during eye closure. Downbeat nystagmus appeared on midline position even during eye closure in six patients. An electrooculography was demonstrated in three out of above six patients. A 24-year-old woman (Case 1) complained of a single spell of vertigo. There was no remarkable finding on neurological examination. An audiogram was an abrupt type sensorineural hearing loss in both ears. A caloric test was normal. Horizontal and vertical smooth pursuit was normal. Optokinetic nystagmus showed normal response in both horizontal and vertical planes. Both eyes were elevated on eye closure. They were depressed to the midline position with mental task and downbeat nystagmus appeared. A 68-year-old man (Case 2) had a history of dizziness on walking of three-year duration. On examination neurological findings were normal. A caloric test was normal in both ears. Optokinetic nystagmus and smooth pursuit were normal in both horizontal and vertical eye recordings. He had a transient eye elevation on eye closure. Both eyes immediately came downward to midline position and downbeat nystagmus was demonstrated. His nystagmus had persisted for four years. A 68-year-old woman (Case 3) complained of positional vertigo of seven-month duration. Neurological findings were normal. A caloric test was normal. There was a conductive hearing loss on the left ear. The right ear showed a normal audiogram.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1981

Physiological and psychological functions of human organism under different light conditions.

At the present time, we are engaged in the introduction of further methods, originally destined for clinical praxis, i.e. electrooculography (for laboratory purposes worked out by Manák) and electroretinography (worked out by Peregrín and Svĕrák). This complex of methods, one part of which we can use even in field research in such situations where as standardized visual challenge the proper type of work of the tested persons is of use, makes it possible to evaluate the luminous conditions differing each from other qualitatively and quantitatively.

Adaptation, Ocular↗
PubMed1995

Selective cone dystrophy with protan genotype.

PURPOSE: To determine the functional defects in two male patients with progressive cone dystrophy and hybrid L-M cone pigment genes. METHODS: Clinical evaluation, standard electroretinography, and electrooculography were performed in two affected patients and two family members. Measurements of spectral sensitivity and transient tritanopia were made in both patients. RESULTS: In the patients, visual acuity varied between 20/50 and 20/100. The electroretinogram showed reduced flicker responses. When light adapted, a-wave amplitudes were borderline, but b-wave amplitudes were reduced severely. Electroretinography with chromatic stimuli showed a difference between well-preserved responses to green and markedly reduced responses to red stimuli. Spectral sensitivity measurement revealed a lack of L (long-wavelength sensitive; red) cone function and normal function of the S (short-wavelength sensitive; blue) and M (middle-wavelength sensitive; green) cones. Transient tritanopia was abnormal, indicating a severe disturbance of cone-cone interaction. CONCLUSIONS: Progressive cone dystrophy with predominant dysfunction of L cones exists in both patients. The cone dystrophy may be caused by a rearrangement of the X-chromosome pigment gene array that is associated with the deletion of L-cone sequences and the formation of hybrid L-M cone pigment genes. It cannot be excluded, however, that both patients have protanopia and that cone dystrophy developed because of other causes.

Adult↗
PubMed1994

Twenty-four-hour blood pressure control: effect of cilazapril on continuous arterial blood pressure during sleep, and physical and mental load in patients with arterial hypertension and sleep apnea.

To assess the effectiveness of cilazapril in regulating blood pressure (BP) in patients with sleep-related breathing disorders, 23 male patients (mean age, 50 years; mean body mass index, 32.7 kg/m2) with a mean apnea/hypopnea index of 49.7 and arterial hypertension (163/104 mm Hg) participated in a placebo-controlled, randomized, double-blind study. They received either cilazapril, 2.5 mg/day (n = 12) or placebo (n = 11). The effects of treatment were studied under different conditions of sleep and physical and mental load before and after 8 days of treatment. Measurements by night included cardiorespiratory polysomnography, inductive plethysmography, pulse oximetry and nasal air flow, electroencephalography, (EEG), electrooculography and electromyography, (ECG), and blood pressure (BP). Measurements by day (ECG, heart rate, and BP) were performed at rest and under physical and mental load. Systolic, diastolic, and mean BP (5 min at night; 1 s during the day), heart rate, apnea and hypopnea index, EEG data, and test reaction times were compared in both groups. The systolic and diastolic BP of patients receiving cilazapril was lower compared to baseline for all physical and mental loads. Mean BP reductions over all standardized loads was greater with cilazapril than placebo (-10 vs. -4.3 mm Hg, p < 0.05). These results show that BP is influenced similarly by mental and physical loads, and that behavior [i.e., awake state and non-rapid eye movement and rapid eye movement (NREM and REM) sleep determines BP regulation. Cilazapril is effective in reducing BP in all situations, especially during REM sleep hypertension.

Adult↗
PubMed1994

Clinical visual electrophysiology in China.

With the development of modern ophthalmology in the past 40 years, great progress has been made in visual electrophysiology in terms of clinical application, basic research and academic exchange in China. A series of visual electrophysiological measurements, such as electroretinography (ERG), evoked early response (ERP), electrooculography (EOG), visual evoked potential (VEP), which are assisted with various stimuli and computer analysis, have been used in testing different layers of the visual system. Some new relevant techniques have been developed and the academic organizations established. These demonstrate that clinical visual physiology has entered a new period of development.

China↗
PubMed1994

Visual readaptation after flash exposure under scotopic conditions. A study using optokinetic nystagmus as an indicator of visual perception.

The purpose of the present study was to establish a method for objective measurements of visual readaptation after flash exposures and to define a model for measurements. Influences of target direction, luminance and velocity on optokinetic nystagmus (OKN) were investigated under scotopic conditions. Visual readaptation was measured using OKN as an indicator of visual perception after exposure to a flash. The interval between the triggering of the flash and the reoccurrence of OKN was defined as the visual readaptation time (RAT). A Goldmann perimeter hemisphere was used for flash stimulation. A horizontally moving vertical grating projected inside the hemisphere was used as the OKN stimulus. Eye movements were recorded by DC electrooculography (EOG). The dependence of RAT on the dose of the flash, the wavelength of the flash and the luminance of the OKN target were investigated. The precision of the measurement method was studied. This includes the analysis of the variance due to the experimental occasions, the repeated exposures, the sexes of the subjects, the methods for recognition of OKN and the ways of visual adaptation before measurements. The contributions of retinal receptor and the neural activity to RAT were investigated by electroretinography (ERG). The influences of target direction and luminance on binocular motion perception and OKN as well as monocular OKN were examined at various target velocities. The dependence of the frequency and amplitude of eye jerks during monocular OKN on target luminance and velocity were also examined. It was found that RAT increases with increasing doses of the flash or decreasing luminance of the grating. RAT is most extended after flashes near 520 nm. RAT does not differ between experimental occasions, between a manual and a semi-automatic method for recognition of OKN, between the sexes and between goggle adaptation and ordinary dark adaptation. There is a reduction of RAT due to repeated flash exposures. The data collected indicate that a well-defined model is crucial for measurements of RAT. The measurement of ERG showed that RAT is mediated by both retinal receptor and the neural activities. The receptor component depends on the wavelength of the flash while the neural component is wavelength-independent. Moreover, it was found that motion perception and OKN gain does not differ between right and left target directions. For a given target velocity, motion perception and OKN gain under both binocular and monocular viewing conditions increase with increasing luminance of the target with an exponential decay. The maximum OKN gain decreases as target velocity increases.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Ocular↗