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[A case of HTLV-I associated myelopathy with flutter-like oscillation].

We reported a 37-year-old woman showing HTLV-I associated myelopathy (HAM) with flutter-like oscillation of the eyes. She had a 15-year history of spastic paraplegia and noticed visual quaking at the age of 37 years. On neurological examination, she showed spasticity in both lower extremities, hyperreflexia in the extremities, neurogenic bladder, and transient, horizontal and pendular ocular oscillation. Anti HTLV-I antibody titers in serum and cerebrospinal fluid were significantly elevated. Brain CT scan revealed no particular abnormalities. In electrooculography, the oscillation consisted of 2 to 4 pendular cycles, having an amplitude of 3 to 10 degrees, and lasting 0.3 to 0.8 second. It occurred immediately after change of fixation at the lateral gaze. This flutter-like oscillation has been thought to result from disorders of cerebellum and its peduncles since the first description by Cogan (1954). Cerebellar signs, although infrequent, have been reported to occur in the patients with HAM. From the present study, flutter-like oscillation should be added as one of cerebellar signs which can occur in patients with HAM.

Adult↗

Hexadecylphosphocholine may produce reversible functional defects of the retinal pigment epithelium.

Hexadecylphosphocholine is a synthetic phospholipid derivative that has antitumor activity due to its interference with membrane functions. Animal experiments have shown photoreceptor and retinal pigment epithelium (RPE) degeneration after its systemic application. In a phase II trial of hexadecylphosphocholine therapy in 23 patients with advanced metastatic colorectal or lung cancer, visual acuity and color vision testing, slit-lamp examination, tonometry, fundoscopy (including photodocumentation), visual field testing, electrooculography (EOG), and electroretinography (ERG) were performed. A baseline examination was carried out prior to therapy. Patients were reexamined after 2 months and after 5 months. In all, 71% of the patients had a reduced light peak in the EOG during therapy. After the end of therapy the light peak improved again and became normal in most patients. The statistical analysis showed that the light-peak values during therapy were significantly lower than the baseline and posttreatment values. This indicates that hexadecylphosphocholine might be capable of producing a partly reversible functional defect of the RPE. Apart from this finding, no other functional or morphological ocular side effect was detected. The functional changes observed in our patients as well as the morphological changes found in animal experiments are similar to those reported for known diseases of the RPE-photoreceptor complex. Therefore, hexadecylphosphocholine-induced retinopathy might become useful as an animal model for such diseases.

Adenocarcinoma↗

Alternations of eye movements induced by visual stimulation in a patient with acute cerebellar infarction.

We had the opportunity to investigate a patient with acute cerebellar infarction with edema that extended to the brainstem, using CT-scan and electrooculography (EOG). The purpose of this paper was to analyze the pursuit eye movements, saccades, optokinetic nystagmus (OKN) and fixation-suppression of the caloric test in an acute cerebellar infarction and on CT-scans to evaluate the connections between eye movements and lesions in the vestibulocerebellum. At the onset of infarction, data of the eye movements suggested that the lesioned area involved the bilateral dorsal pontine tegmentum and bilateral cerebellum, although the left side was predominantly impaired, as judged from the CT-scans. After more than 3 weeks from onset, deviation of the fourth ventricle and compression to the brainstem due to edema were not observed. Nevertheless, the parameters of conjugate eye movements that were analyzed had not recovered completely. This suggests that impairment of a neural integrator may still exist.

Acute Disease↗

Visual influence on head shaking using the vestibular autorotation test.

In this study we investigated the vestibular system by recording eye movements in response to voluntary high-frequency head-only movements using the Vestibular Autorotation Test (VAT; Western System Research Inc., Los Angeles, California). Our objective was to evaluate if the VAT could be implemented as one of the screening tests for vestibular integrity in aircrews and potential pilots. We attempted to record horizontal and vertical eye movements using electrooculography and head velocity with calibrated rotational velocity sensors. The gain and phase of the input and output signals were computed by discrete Fourier analysis. Seated subjects were instructed to fixate on a real or imaginary target while making smooth head oscillations about the spinal axis in time to an audible cue from 0.5 to 6.0 Hz/during an 18-second test period. Test trials included two conditions in the light with subjects fixated on a real target (C1) or on an imaginary target on a blank screen (C2); three conditions in the dark in which subjects fixated on an imaginary target (C3), fixated on a remembered LED target in the dark after it was extinguished (C4), or fixated on a real target (C5). All the dark trials were performed after dark adaptation for 30 minutes. We were not able to obtain consistent vertical VOR response (when the subjects oscillated their head about the interaural axis) using the VAT. For horizontal eye movements from 2.0 to just over 4.7 Hz, when subjects fixated on an imaginary target, there was an unexpected and significant increase in the gain of the eye movement velocities in the dark as compared to the gain obtained in the light conditions. In the dark trials, the gain was significantly higher when the subjects fixated on an imaginary target as opposed to a real target. There was no difference in phase among all conditions. This test could potentially serve for preliminary screening for the integrity of the vestibular system as it is noninvasive and of short duration. However, caution must be exercised in controlling various variables. Extensive normative data are needed to properly assess this test as a screening tool for aircrews.

Adult↗

Eye movement abnormalities in a case of Tourette syndrome.

Tourette syndrome (TS) is a neuropsychiatric disorder that is characterised by the presence of multiple vocal, facial, and motor tics which change with time, and a number of other behavioural phenomena. Previous studies have not revealed any ocular-motor abnormalities. We report the eye movement studies of a patient with TS, using electrooculography and simultaneous video recording. Intrusive saccades occurred during smooth pursuit and optokinetic nystagmus. Reflexive and voluntary saccades were dysmetric and there was a complete failure of antisaccades. These abnormalities are characteristic of disease of the frontal lobes and basal ganglia. We review the literature with respect to the eye movement abnormalities associated with TS.

Adolescent↗

A long-term follow-up of metallic intraocular foreign bodies, employing diagnostic x-ray spectrometry.

We describe 10 eyes harboring metallic intraocular foreign bodies (IOFBs) for 9 to 46 years that had undergone diagnostic x-ray spectrometry to measure metal dissolution 9 years before this study. Findings from the present clinical and laboratory examinations, including perimetry, electroretinography, electrooculography, and diagnostic x-ray spectrometry examinations are reported. Deterioration in visual acuity consequent to metal dissolution of the IOFB was found in only one eye. Visual fields and electrophysiologic performances deteriorated in two other eyes for reasons that were probably unrelated to IOFB dissolution. Visual functions remained stable during the follow-up period in seven eyes, although excess copper levels were demonstrated in one of them. Eight of 10 eyes retained visual acuity of 6/24 or better. Diagnostic x-ray spectrometry confirmed siderosis in one patient and ruled out metallosis in the two patients with deteriorated vision for reasons that were unrelated to metallosis. The favorable outcome of this series of patients may influence one to consider a more conservative approach in the decision to remove IOFBs. A careful, life-long follow-up might be considered with periodic electroretinographic and diagnostic x-ray spectrometry examinations; the IOFB should be promptly removed if and when metallosis with damage to visual functions is demonstrated.

Adult↗

Are there ethnic differences in sleep architecture?

The possibility of ethnic differences in sleep architecture was initially examined in conjunction with studies of sleep apnea (study 1). This possibility was then examined in another cohort of patients to determine whether the results might generalize (study 2). Polysomnography was obtained in both cohorts as part of larger protocols investigating sympathetic nervous system activity, blood pressure, and sleep. Sleep monitoring took place in an inpatient clinical research center of a university hospital. Study 1 focused on sleep apnea physiology and involved volunteers with sleep apnea who were otherwise healthy. Study 2 focused on differences in stress reactivity between American Black and White subjects and involved hypertensive and normotensive volunteers who were otherwise healthy. Analyses include 61 participants from study 1 and 35 participants from study 2. Ethnicity in both cohorts was determined by self-report. Participants in both studies were monitored during sleep with traditional polysomnography including electroencephalography (EEG), electromyography (EMG), electrooculography (EOG), and oximetry. In Study 1, Blacks had longer TST (P < 0.01), more REM sleep (P < 0.05), and less WASO (P < 0.05) than Whites. After controlling for RDI, Blacks had longer TST and spent a smaller percentage of time in deep sleep (P < 0.05). In study 2, Blacks had longer TST and REM sleep, lower percent deep sleep, and lower percent deep sleep controlling for RDI (P < 0.05). In two separate studies, Blacks had longer TST, more minutes of REM, and lower percentage deep sleep. These findings suggest possible ethnic differences in sleep architecture.

Black or African American↗

Predictive control of eye movements in Parkinson disease.

Four parkinsonian patients who had shown evidence of an impairment of predictive manual control and 4 age-matched normal subjects were tested for the predictive control of eye movements. Subjects tracked a target with their eyes as it moved in either irregular "noise" or regular (predictable) linear ramp or sine waveforms. Eye movements were monitored by electrooculography, and the overall tracking time lag for each condition was determined by cross-correlation. Both normal and parkinsonian subjects showed prediction in eye tracking on the regular waveforms (zero time lag or anticipation of the target track), indicating that (1) the parkinsonian loss of predictive control in manual tasks is not due to defective control of eye movements, and (2) there may be separate predictor mechanisms in the brain for eyes and hands.

Adult↗

An autosomal dominant syndrome of hemiplegic migraine, nystagmus, and tremor.

A mother and son suffer from hemiplegic migraine with onset in childhood. Both have nystagmus which has not changed for many years, but the date of onset is uncertain. They have an asymmetrical tremor, clinically indistinguishable from essential tremor. Neuroophthalmological examination revealed inability to produce smooth pursuit, gaze-paretic nystagmus, rebound nystagmus, failure of fixation suppression of the vestibuloocular reflex both horizontally and vertically, and low gain of the optokinetic system. These abnormalities, confirmed by electrooculography, are commonly seen in disease of the cerebellum and brainstem. Treatment with propranolol and pizotyline lessened the number of episodes of hemiplegia and improved the tremor. Hemiplegic migraine has been reported in association with nystagmus, retinal degeneration, deafness, and ataxia in varying combinations in three other families with autosomal dominant inheritance. These associated neurological manifestations likely represent system degenerations rather than the effect of repeated ischemia imputable to the migraine itself. The syndrome of hemiplegic migraine, tremor, and ocular smooth pursuit system disorder seen in this family appears to be inherited as a single autosomal dominant trait, although more than one autosomal dominant gene may be involved.

Adolescent↗

Tobacco-induced primary-position upbeat nystagmus.

The effects of tobacco smoking on the eye movements of normal human subjects were studied using direct current electrooculography and the magnetic search coil technique. Tobacco induced a transient primary-position upbeat nystagmus in the dark, which was suppressed by visual fixation. It obeyed Alexander's law and was associated with oblique upward fast phases that alternated from side to side. Tobacco-induced nystagmus exhibited a latency of onset at 40 to 90 seconds, a duration of 10 to 20 minutes, and maximum slow-phase velocities at 2 to 3 minutes. We suggest that tobacco induces primary-position upbeat nystagmus through the excitatory effects of nicotine on the central vestibular pathways.

Adult↗

Epileptic nystagmus.

We report a 52-year-old woman with episodes of vertigo accompanied by right beating nystagmus and left posterior temporoparietal sharp waves and spikes on electroencephalogram without change in level of consciousness. Electrooculography demonstrated that the episodes of nystagmus were not preceded by gaze deviation and that nystagmus slow component velocities were linear. This patient's epileptic nystagmus may have been the result of excitation of cerebral ocular pursuit pathways.

Electroencephalography↗

Disturbance of rapid eye movement sleep in spinocerebellar ataxia type 2.

Five genetically confirmed spinocerebellar ataxia type 2 (SCA2) patients were admitted to our sleep laboratory for two all-night video-polysomnographies. A standard montage was used, including electroencephalography, vertical and horizontal electrooculography, electromyography of mental, submental, and tibialis anterior muscles, and respiratory monitoring. Four of five SCA2 patients had insufficient muscle atonia during rapid eye movement (REM) sleep. All patients exhibited myoclonic jerks during REM sleep, while elaborated behavior was not observed in the video. Abnormal motor control during sleep with periodic leg movements and REM sleep without atonia occurs frequently in SCA2. This finding may reflect a dysfunction of dopaminergic and/or brainstem and cerebellar outflow pathways.

Adult↗

The influence of head position and head reorientation on the axis of eye rotation and the vestibular time constant during postrotatory nystagmus.

Reorienting the head with respect to gravity during the postrotatory period alters the time course of postrotatory nystagmus (PRN), hastening its decline and thereby reducing the calculated vestibular time constant. One explanation for this phenomenon is that the head reorientation results in a corresponding reorientation of the axis of eye rotation with respect to head coordinates. This possibility was investigated in 10 human subjects whose eye movements were monitored with a three-dimensional magnetic field - search - coil technique using a variety of head reorientation paradigms in a randomized order during PRN following the termination of a 90 degrees/s rotation about earth vertical. Average eye velocities were calculated over two time intervals: from 1 s to 2 s and from 7 s to 8 s after cessation of head rotation. The time constant was estimated as one third of the duration of PRN. For most conditions, a reorientation of the head with respect to gravity 2 s after the rotation had stopped did not significantly alter the direction of the eye velocity vector of PRN with respect to head coordinates. This strongly indicates that, in humans, PRN is mainly stabilized in head coordinates and not in space coordinates, even if the otolith input changes. This finding invalidates the notion that the shortening of PRN due to reorientation of the head could be due to a change of the eye velocity vector towards a direction (torsion), which is not detectable with the eye recording methods (electrooculography) used in earlier studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[A new method for calibration of electrophysiological recording systems (author's transl)].

The method described in this paper permits determination of amplification, band-pass properties, and electrode impedance in electrophysiological experimental setups. The battery powered test-signal generator drives square-wave current pulses through a 2 ohm resistance, which acts as a source of 100 muV p-p pulses. The 2 ohm resistor is wired in series with one of the electrode leads and remains there permanently. For calibration of the above-mentioned properties, one need only turn the generator on, without changing the measurement setup. By observing the shape of the square waves after passing through the system, it is possible to judge the band-pass characteristics of the entire system. Electrode impedance may be measured by putting a (variable) resistor in parallel with the preamplifier input. The test signal current is of the same order of magnitude as currents from biological signal sources. This method makes working with electrophysiological measurement systems which are used in electroretinography, electrooculography, and recording of visually-evoked cortical potentials in ophthalmology much easier.

Amplifiers, Electronic↗

Flecked chorioretinopathy associated with Birt-Hogg-Dubé syndrome.

BACKGROUND: Birt-Hogg-Dubé's syndrome is a rare skin disease characterized by multiple trichofibromas of the skin and polyps of the intestine. Ophthalmologic manifestations associated with the syndrome have not been reported in detail. CASE REPORTS AND METHODS: Two siblings suffering from Birt-Hogg-Dubé syndrome were examined clinically. Electrooculography and electroretinography were performed according to international standards. Color fundus photographs were taken as well as fluorescein angiograms. The two patients showed multiple perifollicular fibromas and trichodiscomas of the skin of the head. Funduscopy and fluorescein angiography revealed a flecked chorioretinopathy in one patient with progressive constriction of visual fields and severely reduced electroretinographic responses. Ophthalmoscopy in his sister showed peripheral pigmentary changes with only minor functional abnormalities. CONCLUSION: These findings suggest that Birt-Hogg-Dubé syndrome may be associated with a progressive flecked chorioretinopathy with constricted visual fields and that patients with the syndrome should undergo ophthalmological examination.

Aged↗

Electrophysiological brainstem investigations in obstructive sleep apnoea syndrome.

Phasic inspiratory genioglossus activity prevents pharyngeal airway collapse in healthy subjects during sleep and is diminished or absent in obstructive sleep apnoea syndrome (OSAS), thus leading to pharyngeal obstruction. Case reports of OSAS after pontomedullary lesions indicate that impaired inspiratory genioglossal activity may result from brainstem lesions. We therefore investigated brainstem functions in 18 awake patients with OSAS using brainstem auditory evoked potentials, blink reflex, masseter reflex, masseter inhibitory reflex (in 11 of 18 patients), magnetic evoked potentials of the tongue and electrooculography with vestibular testing. Fifteen of 18 patients showed no electrophysiological abnormalities. One patient had a left pontine and two patients a bilateral pontomesencephalic lesion, although a causal connection with OSAS was not conclusively confirmed. Our results do not support the assumption of a relevant structural brainstem lesion in OSAS patients with normal neurological findings.

Adult↗

[Electrophysiological studies in breast carcinoma patients with tamoxifen retinopathy].

PURPOSE: Crystalline plaques in the cornea or the retinal nerve fiber layer are well-known side effects of tamoxifen therapy. We investigated whether electrophysiological methods for determining the function of the retinal nerve fiber layer and retinal pigment epithelium demonstrate changes in tamoxifen retinopathy. PATIENTS AND METHODS: We compared the right eyes of four women with breast cancer and mono- or bilateral tamoxifen retinopathy to ten right eyes of age-matched, eyehealthy patients who had not received tamoxifen by means of electrophysiological investigations (e.g., pattern-reversal electroretinography, flash electroretinography for the maximal combined response, electrooculography; ISCEV standard conditions). RESULTS: No significant differences were observed between patients with tamoxifen retinopathy and controls regarding mean visual acuity, basal level of the electro-oculographic standing potential, basal level on the Arden index, or any of the other electrophysiological potentials. CONCLUSIONS: Pattern-reversal electroretinographic measurements revealed no damage of retinal ganglion cells in the presence of crystalline plaques in the retinal nerve fiber layer. Electro-oculography did reveal differences, but these were not statistically significant, possibly due to the small number of cases.

Aged↗

Does abnormal neuronal excitability exist in myotonic dystrophy? I. Effects of the antiarrhythmic drug hydroquinidine on slow saccadic eye movements.

The abnormal neuronal excitability hypothesized in myotonic dystrophy (MD) might contribute to psychomotor and behavioral disturbances of MD patients. To gain new insights into the pathophysiology of MD, we determined whether the antiarrhythmic drug hydroquinidine would ameliorate slow saccadic eye movements (SEMs), apathy and hypersomnia in MD patients. SEMs were selected as simple modality for psychomotor investigation. The study was conducted in a randomized, placebo-controlled, double-blind, crossover manner. Ten ambulatory patients without contraindications to hydroquinidine administration were enrolled. Hydroquinidine (450 mg/day) or placebo was given orally for 6 weeks with a washout period of 6 weeks between treatments. SEMs were recorded by electrooculography and analyzed by a computer system. Two patients withdrew in the first week of active treatment because of nausea and epigastralgia. Hydroquinidine significantly increased the normalized peak saccadic velocity and shortened the saccadic reaction time compared to placebo. The drug's effects on apathy and hypersomnia are presented in a companion paper.

Adult↗