BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.
Eye Movements ; Head ; Heredity ; Humans ; Nystagmus, Congenital* ; Nystagmus, Optokinetic ; Phenotype ; Pursuit, Smooth ; Reflex, Vestibulo-Ocular ; Saccades ; Strabismus ; Vision Disorders

BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.
Eye Movements ; Head ; Heredity ; Humans ; Nystagmus, Congenital* ; Nystagmus, Optokinetic ; Phenotype ; Pursuit, Smooth ; Reflex, Vestibulo-Ocular ; Saccades ; Strabismus ; Vision Disorders

BACKGROUND AND OBJECTIVES: Although disequilibrium is common type of dizziness in older people, it is sometimes difficult to identify a specific cause for this problem. The diffuse brain pathology including subcortical ischemia and atrophy can be a cause for patients with disequilibrium of unknown cause. Aim of this study is to identify the eye movements and neuroimaging features in patients with disequilibrium. MATERIALS AND METHODS: We performed a prospective investigation in patients with disequilibrium of unknown cause. We collected information on demographic characteristics and clinical features of disequilibrium. The impact of dizziness on everyday life was assessed by 25-item dizziness handicap inventory (DHI). Vestibular function test (VFT) includes smooth pursuit, saccade, optokinetic nystagmus, and rotatory chair test. Subcortical white matter lesions and brain atrophy were graded from brain magnetic resonance image (MRI). RESULTS: This study included 14 patients (12 female and 2 male), aged between 64 and 84 years, mean age 74.01+/-6.02 years. The score of DHI was 39.4+/-11.8 (20-58). Eye movements were abnormal in 13 patients and normal in only one patient. The degree of subcortical ischemia was mild in 7, moderate in 4, and severe in 3 patients. Ventricular brain ratio was 0.23+/-0.03. However, there was no significant relationship between MRI findings and the degree of oculomotor alterations (result of VFT). CONCLUSION: Patients with disequilibrium of unknown cause are usually elderly women. Alterations in oculomotor movements and diffuse brain pathology including white matter lesions and atrophy were observed in patients with disequilibrium of unknown cause.
Aged ; Atrophy ; Brain ; Brain Diseases ; Brain Ischemia ; Dizziness ; Eye Movements ; Female ; Humans ; Ischemia ; Magnetic Resonance Imaging ; Neuroimaging ; Nystagmus, Optokinetic ; Prospective Studies ; Pursuit, Smooth ; Saccades ; Vestibular Function Tests

Normally, the fast phase of optokinetic nystagmus (OKN) beats on the opposite direction to the movement of an optokinetic stimulus. The fast component of OKN beating in the same direction are called "reversed OKN". Eventhough the mechanism of reversed OKN is still disputed, it is well known that reversed OKN occurs exclusively in patients with congenital nystagmus, or in some cases, with acquired neurologic disease. It is easy to diagnose the congenital nystagmus when the spontaneous nystagmus can be seen at birth. But when the congenital nystagmus can be seen only on eccentric gaze or when the patient has a wide neutral region around the primary position, the abnormal eye movement can not be detected until a medical examination is performed. It is thought that causes of reversed OKN may be the abnormal neural decussation of the visual system or spontaneous nystagmus. Recently, we experienced two cases of bidirectional reversed OKN as a congenital nystagmus. One patient had bilateral reversed optokinetic nystagmus and gaze evoked nystagmus, whereas the other patient had periodic alternative nystagmus and bilateral reversed OKN. Bilateral reversed OKN may be one of the pathognomic signs of congenital nystagmus.
Eye Movements ; Humans ; Nystagmus, Congenital ; Nystagmus, Optokinetic* ; Parturition

A Foville syndrome is rare. A 46-year-old man with a 3-year history of Behcet's disease presented with a right facial palsy and a limitation in the rightward movements of the eyes. On neurologic examination, there was no movement of eyes in the right hemifield during all kinds of eye movements, including saccade, smooth pursuit, vestibulo-ocular reflex, and optokinetic nystagmus. However, all the eye movements were normal in the left hemifiled except for slowed saccades toward the right. Additional features were right infranuclear facial paresis and extensor plantar response on left side. Brain MRI revealed high signal intensity lesions in the right pons both in the dorsal tegmentum and in the basis. Neurological signs resolved gradually with steroid treatment. Different clinical features between abducens nucleus syndrome and paramedian pontine reticular formation syndrome are briefly discussed. To the authors' knowledge, this is the first case report of a Foville syndrome caused by neuro-Behcet's disease.
Brain ; Brain Stem Infarctions* ; Eye Movements ; Facial Paralysis ; Humans ; Magnetic Resonance Imaging ; Middle Aged ; Neurologic Examination ; Nystagmus, Optokinetic ; Pons ; Pursuit, Smooth ; Reflex, Babinski ; Reflex, Vestibulo-Ocular ; Reticular Formation ; Saccades

Biomechanical Phenomena ; Eye Movements ; Neurons/physiology* ; Pursuit, Smooth ; Saccades

BACKGROUNDReading Chinese, a kind of ideogram, relies more on visual cognition. The visuospatial cognitive deficit of Chinese dyslexia is an interesting topic that has received much attention. The purpose of current research was to explore the visuopatial cognitive characteristics of Chinese dyslexic children by studying their eye movements via a picture searching test.

METHODSAccording to the diagnostic criteria defined by ICD-10, twenty-eight dyslexic children (mean age (10.12 +/- 1.42) years) were enrolled from the Clinic of Children Behavioral Disorder in the third affiliated hospital of Sun Yat-sen University. And 28 normally reading children (mean age (10.06 +/- 1.29) years), 1:1 matched by age, sex, grade and family condition were chosen from an elementary school in Guangzhou as a control group. Four groups of pictures (cock, accident, canyon, meditate) from Picture Vocabulary Test were chosen as eye movement experiment targets. All the subjects carried out the picture searching task and their eye movement data were recorded by an Eyelink II High-Speed Eye Tracker. The duration time, average fixation duration, average saccade amplitude, fixation counts and saccade counts were compared between the two groups of children.

RESULTSThe dyslexic children had longer total fixation duration and average fixation duration (F = 7.711, P < 0.01; F = 4.520, P < 0.05), more fixation counts and saccade counts (F = 7.498, P < 0.01; F = 11.040, P < 0.01), and a smaller average saccade amplitude (F = 29.743, P < 0.01) compared with controls. But their performance in the picture vocabulary test was the same as those of the control group. The eye movement indexes were affected by the difficulty of the pictures and words, all eye movement indexes, except saccade amplitude, had a significant difference within groups (P < 0.05).

CONCLUSIONSChinese dyslexic children have abnormal eye movements in picture searching, applying slow fixations, more fixations and small and frequent saccades. Their abnormal eye movement mode reflects the poor ability and strategy of visual information processing.

Child ; Cognition ; Dyslexia ; physiopathology ; psychology ; Eye Movements ; Female ; Fixation, Ocular ; Humans ; Intelligence Tests ; Male ; Saccades

BACKGROUND AND OBJECTIVES: Qualitative oculomotor abnormalities have been reported in parkinsonian patients for many years, but conflicting results have been obtained. This study was performed to evaluate the correlation between the severity of the disease and the abnormalities of the ocular movements in idiopathic parkinson's disease. METHODS: We gave the vestibular function tests in patients with idiopathic parkinson's disease and normal controls. Eye movement recordings were made with automated electronystagmography and rotation test was performed. A total of 46 patients (mean age : 61.2+/-6.7) and 24 controls (mean age : 60.5+/-4.3) were studied. The severity of the disease was divided into two groups by modified Hoehn & Yahr staging ; H-Y stage 1 and 2 as a mild group and stage 3 and 4 as a severe group. RESULTS: Saccadic latency and accuracy, pursuitic gain and velocity, vestibulo-ocular reflex (VOR) suppression by vision were significantly altered in patients, whereas mean velocity of optokinetic nystagmus (OKN) and VOR gain in darkness were normal. Alteration of saccadic latency and accuracy, pursuitic gain and velocity, VOR suppression by vision were profound in the severe group compared with a mild group and controls, but the above parameters did not differ between a mild group and controls. In a hemiparkinson's group, saccadic latency and accuracy, pursuitic gain, OKN mean velocity and gain was not different between the both sides. CONCLUSION: The results indicate that severe Parkinson's disease damages nigrostriatal or other specific pathways which were involved in the regulation of the saccadic, pursuitic and pursuitic-mediated visual fixation system. In a hemiparkinson's group asymmetric damage of dopaminergic innervation which was involved in the regulation of ocular movements was not found.
Darkness ; Electronystagmography ; Eye Movements ; Humans ; Nystagmus, Optokinetic ; Parkinson Disease* ; Reflex, Vestibulo-Ocular ; Vestibular Function Tests

PURPOSE: The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects, and subjects who need legal assistance. We designed an objective system for visual acuity test (SOVAT) consisting of three components: stimuli applied via a suppression method, display and evaluation and made a suppression method as stimuli component for SOVAT. Usefulness of the SOVAT was evaluated. METHODS: The visual stimuli were presented on a high-resolution head-mounted display (HMD). An eye movement tracking program and gaze monitoring device allowed us to monitor the patient's fixation status during the test. The suppression method, in addition to a conventional induction method, was developed to use with the SOVAT and its accuracy and confidence level were evaluated. RESULTS: On the basis of clinical data, we present the reference values for the SOVAT as below. For the induction method, objective visual acuity (smallest pixel size), the presumed subjective visual acuity was 3: 0.35-0.6, 7: 0.05-0.25, 12: below 0.05 and for the suppression method it was 1: 0.6-1.0, 1.5: 0.4-0.7, 3: 0.15-0.4, 5: 0.1-0.2. CONCLUSIONS: SOVAT using this suppression method to assess objective visual acuity proved to be more useful than that with a conventional induction method, especially in the range of high visual acuity.
Eye Movements ; Humans ; Infant ; Nystagmus, Optokinetic ; Organothiophosphorus Compounds ; Reference Values ; Track and Field ; Visual Acuity

The relationships between eye movements and head movements of the primate during gaze shifts are analyzed in detail in the present paper. Applying the mechanisms of neurophysiology to engineering domain, we have improved the robot eye-head coordination. A bionic control strategy of coordinated head-eye motion was proposed. The processes of gaze shifts are composed of an initial fast phase followed by a slow phase. In the fast phase saccade eye movements and slow head movements were combined, which cooperate to bring gaze from an initial resting position toward the new target rapidly, while in the slow phase the gaze stability and target fixation were ensured by the action of the vestibulo-ocular reflex (VOR) where the eyes and head rotate by equal amplitudes in opposite directions. A bionic gaze control model was given. The simulation results confirmed the effectiveness of the model by comparing with the results of neurophysiology experiments.
Bionics ; Eye Movements ; physiology ; Fixation, Ocular ; physiology ; Head Movements ; physiology ; Humans ; Ocular Physiological Phenomena ; Orientation ; Photic Stimulation ; Reflex, Vestibulo-Ocular ; physiology ; Saccades ; physiology