Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Eye Movement Measurements”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1989

The value of measuring saccadic eye movement in the investigation of non-compressive myelopathy.

Saccadic eye movement recording was performed in 53 patients with non-compressive myelopathy. Twenty one patients (40%) had subclinical abnormalities of saccadic movement, supporting a diagnosis of probable multiple sclerosis. When used in addition to the measurement of visual evoked potentials and brainstem auditory evoked responses, the detection of subclinical abnormalities increased from 40% to 57%. The detection rate of abnormalities by saccadic eye movement recording was equal to that of visual evoked responses, but more than of brainstem auditory evoked responses. Prolonged latency of gaze was the most common saccadic latency abnormality detected. The majority of saccadic velocity abnormalities could be explained by disease in the medial longitudinal bundle. An unusual finding was that abduction velocity was increased in six patients. It is concluded that the simple measurement of saccadic eye movement is a valuable addition to other ancillary investigations for the diagnosis of multiple sclerosis. It also allows analysis of oculomotor function, commonly disordered in multiple sclerosis, but rarely investigated.

Adult↗
PubMed1990

Obtaining a quantitative measure of eye movements in human infants: a method of calibrating the electrooculogram.

We have developed a calibration procedure that combines the measurement of the EOG voltage with the concurrent assessment of the actual direction of gaze as revealed by the corneal reflection of a target light. Using this method, we have been able to calibrate the eye-position signal recorded from 2- and 3-month-old infants. Our results show that in young infants (1) the EOG is linearly related to eye position to at least +/- 20 deg; (2) the slopes of the calibration lines measured early and late in the same test session were not significantly different at the 0.1 level; (3) at the most eccentric eye position, the calibration was accurate to within +/- 1 deg; and (4) an abbreviated calibration at 0 and +/- 15 deg, which took less than 2 min, produced essentially the same slope (t-test not significant at the 0.1 level) as a longer procedure that tested at every 5 deg between +20 and -20 deg.

Adult↗
PubMed1998

Age-related performance of human subjects on saccadic eye movement tasks.

We measured saccadic eye movements in 168 normal human subjects, ranging in age from 5 to 79 years, to determine age-related changes in saccadic task performance. Subjects were instructed to look either toward (pro-saccade task) or away from (anti-saccade task) an eccentric target under different conditions of fixation. We quantified the percentage of direction errors, the time to onset of the eye movement (saccadic reaction time: SRT), and the metrics and dynamics of the movement itself (amplitude, peak velocity, duration) for subjects in different age groups. Young children (5-8 years of age) had slow SRTs, great intra-subject variance in SRT, and the most direction errors in the anti-saccade task. Young adults (20-30 years of age) typically had the fastest SRTs and lowest intra-subject variance in SRT. Elderly subjects (60-79 years of age) had slower SRTs and longer duration saccades than other subject groups. These results demonstrate very strong age-related effects in subject performance, which may reflect different stages of normal development and degeneration in the nervous system. We attribute the dramatic improvement in performance in the anti-saccade task that occurs between the ages of 5-15 years to delayed maturation of the frontal lobes.

Adolescent↗
PubMedDate not supplied

Geometric adjustments to account for eye eccentricity in processing horizontal and vertical eye and head movement data.

Neglecting the eccentric position of the eyes in the head can lead to erroneous interpretation of ocular motor data, particularly for near targets. We discuss the geometric effects that eye eccentricity has on the processing of target-directed eye and head movement data, and we highlight two approaches to processing and interpreting such data. The first approach involves determining the true position of the target with respect to the location of the eyes in space for evaluating the efficacy of gaze, and it allows calculation of retinal error directly from measured eye, head, and target data. The second approach effectively eliminates eye eccentricity effects by adjusting measured eye movement data to yield equivalent responses relative to a specified reference location (such as the center of head rotation). This latter technique can be used to standardize measured eye movement signals, enabling waveforms collected under different experimental conditions to be directly compared, both with the measured target signals and with each other. Mathematical relationships describing these approaches are presented for horizontal and vertical rotations, for both tangential and circumferential display screens, and efforts are made to describe the sensitivity of parameter variations on the calculated results.

Eye Movements↗
PubMed2005

Toward an appropriate baseline for measures of eye movement behavior during reading.

In empirical studies of human eye movement behavior during reading, it is common to compute various summary measures from the data, but these measures are typically not evaluated with respect to corresponding measures of baseline performance. The authors present a method for deriving an appropriate baseline by mapping the actual behavior to a random perturbation of the text being read, and they find surprising similarities between the baseline and the empirical data. The practical message from these findings is that the importance of a particular factor in explaining either empirical or simulated eye movement patterns should be evaluated using an appropriate baseline. In addition to this methodological point, the authors suggest that eye movement behavior in reading may be constrained by the properties of an eye-guidance system that has adapted to the coarse-grained statistical properties of written language.

Eye Movements↗
PubMed2004

Altered sensitivity to alcohol in the late luteal phase among patients with premenstrual dysphoric disorder.

BACKGROUND: Affective disorders, and possibly also premenstrual dysphoric disorder (PMDD) are risk factors for alcohol abuse in women. Although the majority of prior studies have indicated that alcohol sensitivity does not differ between menstrual cycle phases, patients with PMDD have thus far not been studied. METHODS: We have evaluated the functional sensitivity to a low dose of alcohol in 12 women with and 12 women without PMDD in the mid-follicular and late luteal phases of the menstrual cycle, by comparing the effects of an intravenous alcohol infusion on a number of saccadic eye movement measures, including saccadic eye velocity (SEV), saccade deceleration, and self-rated levels of intoxication. RESULTS: PMDD patients displayed blunted SEV (p<0.01) and saccade deceleration responses (p<0.01) to alcohol infusion in the late luteal phase compared to the mid-follicular phase. Control subjects, on the other hand, did not change their SEV or saccade deceleration responses to alcohol between cycle phases. CONCLUSION: These findings are compatible with altered saccadic eye movement sensitivity in response to alcohol among PMDD patients, particularly in the late luteal phase of the menstrual cycle.

Adult↗
PubMed1997

Smooth-pursuit eye movements elicited by first-order and second-order motion.

The perception of the displacement of luminance-defined contours (i.e., first-order motion) is an important and well-examined function of the visual system. It can be explained, for example, by the operation of elementary motion detectors (EMDs), which cross-correlate the spatiotemporal luminance distribution. More recent studies using second-order motion stimuli, i.e., shifts of the distribution of features such as contrast, texture, flicker, or motion, extended classic concepts of motion perception by including nonlinear or hierarchical processing in the EMD. Smooth-pursuit eye movements can be used as a direct behavioral probe for motion processing. The ability of the visual system to extract motion signals from the spatiotemporal changes of the retinal image can be addressed by analyzing the elicited eye movements. We measured the eye movement response to moving objects defined by two different types of first-order motion and two different types of second-order motion. Our results clearly showed that the direction of smooth-pursuit eye movements was always determined by the direction of object motion. In particular, in the case of second-order motion stimuli, smooth-pursuit did not follow the retinal image motion. The latency of the initial saccades during pursuit of second-order stimuli was slightly but significantly increased, compared with the latency of saccades elicited by first-order motion. The processing of second-order motion in the peripheral visual field was less exact than the processing of first-order motion in the peripheral field. Steady state smooth-pursuit eye speed did not reflect the velocity of second-order motion as precisely as that of first-order motion, and the resulting retinal error was compensated by saccades. Interestingly, for slow second-order stimuli we observed that the eye could move faster than the target, leading to small, corrective saccades in the opposite direction to the ongoing smooth-pursuit eye movement. We conclude from our results that both visual perception and the control of smooth-pursuit eye movements have access to processing mechanisms extracting first- and second-order motion.

Fixation, Ocular↗
PubMed2004

No difference in responsiveness to a low dose of alcohol between healthy women and men.

The purpose of the current study was to examine gender-related differences in alcohol responsiveness by comparing the effect of a low-dose intravenous alcohol infusion upon saccadic eye movements, self-rated sedation and intoxication scores. The functional sensitivity to a low dose of alcohol in 12 healthy women and 12 healthy men was evaluated by comparing the effects of an intravenous alcohol infusion on a number of saccadic eye movement measures, including saccadic eye velocity (SEV), saccade latency, saccade accuracy, saccade deceleration and self-rated levels of intoxication and sedation. The infusion of a low dose of alcohol induced a decrease in SEV and increased saccade deceleration and self-rated scores of intoxication in both males and females. Saccade accuracy was also significantly deteriorated by alcohol in both groups. The alcohol infusion did not induce any main gender-related differences in the saccade or visual analogue scale measurements. According to the findings of the present study, no gender differences in the responsiveness to a low-dose alcohol infusion were found.

Adult↗
PubMed1978

Apparent movement, eye movements and phoria when two eyes alternate in viewing a stimulus.

Three experiments were conducted to test the hypothesis that the apparent movement of a stimulus when the two eyes are alternately occluded can be explained by phoria and Hering's principles of visual direction. In experiments 1 and 2, the direction of apparent movement, eye position, and eye movements were measured when eye movements did and did not occur. In experiment 3, the magnitude of apparent movement and the extent of phoria were comapred. Results from the experiments 1 and 2 indicated that the direction of apparent movement could be predicted from the direction of phoria, in conjunction with Hering's principles, and was not contingent on eye movements. In experiment 3, a high positive correlation (r = 0.95) between the magnitude of apparent movement and the extent of phoria was obtained.

Eye Movements↗
PubMed2003

Altered control of visual fixation and saccadic eye movements in attention-deficit hyperactivity disorder.

Attention-deficit hyperactivity disorder (ADHD) is characterized by the overt symptoms of impulsiveness, hyperactivity, and inattention. A frontostriatal pathophysiology has been hypothesized to produce these symptoms and lead to reduced ability to inhibit unnecessary or inappropriate behavioral responses. Oculomotor tasks can be designed to probe the ability of subjects to generate or inhibit reflexive and voluntary responses. Because regions of the frontal cortex and basal ganglia have been identified in the control of voluntary responses and saccadic suppression, we hypothesized that children and adults diagnosed with ADHD may have specific difficulties in oculomotor tasks requiring the suppression of reflexive or unwanted saccadic eye movements. To test this hypothesis, we measured eye movement performance in pro- and anti-saccade tasks of 114 ADHD and 180 control participants ranging in age from 6 to 59 yr. In the pro-saccade task, participants were instructed to look from a central fixation point toward an eccentric visual target. In the anti-saccade task, stimulus presentation was identical, but participants were instructed to suppress the saccade to the stimulus and instead look from the central fixation point to the side opposite the target. The state of fixation was manipulated by presenting the target either when the central fixation point was illuminated (overlap condition) or at some time after it disappeared (gap condition). In the pro-saccade task, ADHD participants had longer reaction times, greater intra-subject variance, and their saccades had reduced peak velocities and increased durations. In the anti-saccade task, ADHD participants had greater difficulty suppressing reflexive pro-saccades toward the eccentric target, increased reaction times for correct anti-saccades, and greater intra-subject variance. In a third task requiring prolonged fixation, ADHD participants generated more intrusive saccades during periods when they were required to maintain steady fixation. The results suggest that ADHD participants have reduced ability to suppress unwanted saccades and control their fixation behavior voluntarily, a finding that is consistent with a fronto-striatal pathophysiology. The findings are discussed in the context of recent neurophysiological data from nonhuman primates that have identified important control signals for saccade suppression that emanate from frontostriatal circuits.

Adolescent↗
PubMed2004

The nature of change detection and online representations of scenes.

This article provides evidence for implicit change detection and for the contribution of multiple memory sources to online representations. Multiple eye-movement measures distinguished original from changed scenes, even when college students had no conscious awareness for the change. Patients with amnesia showed a systematic deficit on 1 class of eye-movement measures of change detection, even though conscious awareness was not required for the effect to be observed. The authors' findings suggest that online representations of scenes are (a) built up across viewings, (b) composed of activated information from both long-term and working memory, and (c) directly compared with currently processed information regarding the external world. Subsequent online processing is influenced by these representations even when the results of the comparison are not accessible for verbal report.

Adolescent↗
PubMed2002

Active high-frequency vestibulo-ocular reflex and seasickness susceptibility.

OBJECTIVES/HYPOTHESIS: The vestibular autorotation test (VAT) examines responses to active head oscillations at frequencies between 2 and 6 Hz in the horizontal and vertical planes while the subject is fixating a visible target. At these frequencies, the vestibulo-ocular reflex (VOR) is the main source of eye movement for ocular stabilization, although other visual and somatosensory information interacts with the response. Because the neural mismatch theory places emphasis on multimodal sensory interactions as the cause of motion sickness, using the VAT, which measures eye movements resulting from vestibular, visual, and, to a certain extent, proprioceptive information and depends on the conscious participation and cooperation of the subject, could be of advantage in evaluating individuals with differing susceptibility to motion sickness. The purpose of the present study was to evaluate high-frequency VOR parameters in seamen at the two extremes of the seasickness susceptibility scale. STUDY DESIGN: Cross-sectional, parallel-group design. METHODS: Participants in the study were 35 healthy male volunteers aged 18 to 23 years, of whom 20 were highly susceptible to seasickness and 15 were nonsusceptible. The vestibulo-ocular reflex was evaluated by the VAT at frequencies ranging from 2.0 to 5.9 Hz. RESULTS: The lag of the vertical phase was significantly higher in the susceptible group. A significant interaction was also found between group and frequency, the vertical phase being significantly higher in the 3.9- to 5.9-Hz range. Although no group effect was detected for the lag of the horizontal phase, there was a significant interaction between group and frequency, the horizontal phase being higher in the susceptible group at 5.5 and 5.9 Hz. No significant group differences were found for horizontal or vertical gain. CONCLUSIONS: The present findings support the contention that the VAT, which measures eye movements resulting from multimodal vestibular, visual, and, to a certain extent, proprioceptive information and depends on the conscious participation and cooperation of the subject, may produce different results in subjects at the two extremes of the seasickness susceptibility scale. Despite the statistical differences that were found, VAT measurements could not be used for practical purposes to categorize individual motion sickness susceptibility.

Adolescent↗
PubMed1984

Precise non-contacting measurement of eye movements using the corneal reflex.

Using a real-time, analog, zero-crossing technique, it is possible to locate the centre of the corneal reflex of a collimated infra-red beam accurately. Performance at tracking horizontal eye movements in this manner is similar to contact lens techniques. System noise is less than 30 are sec; dynamic range is 30 arc sec to 36 deg; linearity is 2%; data are currently sampled at 1 kHz; velocity resolution, for a velocity bandwidth of 125 Hz, is 2 deg/sec. With automatic acquisition of the corneal reflex, the subject can be set up for measurement within a 1 min time period. Recordings of residual eye movements of fixation and of a wide range of saccades are comparable with previous findings. Post-saccadic oscillations can be resolved for all sizes of saccades. The amplitude-peak-velocity characteristic of saccades is illustrated.

Blinking↗
PubMed2003

Neuropsychological and neurophysiological findings in individuals suspected to be at risk for schizophrenia: preliminary results from the Basel early detection of psychosis study - Früherkennung von Psychosen (FEPSY).

OBJECTIVE: Our study aims to establish a scientific basis for the very early detection of patients at risk for schizophrenia during the nonspecific prodromal phase of the disorder and to predict its outbreak. METHOD: A multidomain approach is used. After screening, approved psychopathological, neurophysiological, neuropsychological and neuroradiological investigations are used to assess a sample of individuals suspected to be at risk for schizophrenia. RESULTS: Neuropsychological and fine motor functioning tests as well as eye movement measurements showed statistically significant differences (P<0.01) between individuals suspected to be at risk for schizophrenia and healthy controls. CONCLUSION: Individuals suspected to be at risk for schizophrenia show specific impairments in various investigations including neuropsychological and fine motor functioning tests as well as eye movement measurements. A set of methods sensitive to even subtle changes in normal functioning may prove useful in predicting the subsequent outbreak of schizophrenia.

Adult↗
PubMed2000

Eye movement task measures inhibition and spatial working memory in adults with schizophrenia, ADHD, and a normal comparison group.

Schizophrenia and attention deficit/hyperactivity disorder (ADHD) are both associated with deficits in inhibition and working memory, although in ADHD the working memory deficit is hypothesized to be secondary to the inhibitory deficit. This similarity in cognitive processes has been paralleled by similarities across the two groups in the performance of working memory and inhibition tasks. The delayed oculomotor response task is an alternative task, which may allow greater separation of working memory from inhibitory components, and thus its use may provide additional information on primary vs. secondary deficits in these disorders. Ten young adult ADHD sufferers, 10 schizophrenic subjects, and 10 normal subjects were matched on age, gender, and education. Eye movements were recorded during delayed oculomotor response tasks with 1- and 3-s delays. Both the ADHD and the schizophrenic subjects demonstrated dis-inhibition (an increased percentage of premature saccades); however only schizophrenic subjects demonstrated an impaired working memory (decreased spatial accuracy of the remembered saccade). The results are consistent with the hypothesis that working memory is a primary deficit in schizophrenia, but secondary to the inhibitory deficit in ADHD.

Adult↗
PubMed2002

Effects of 5 weeks of administration of fluoxetine and dothiepin in normal volunteers on sleep, daytime sedation, psychomotor performance and mood.

This was a placebo-controlled, double-blind randomized crossover study of long-term (5 weeks) administration of fluoxetine (20 mg/day) and dothiepin (75 mg/day for 1 week followed by 150 mg/day for 4 weeks) in 12 healthy male volunteers. Subjects were studied on day 10 and day 36 of treatment, with tests of nocturnal sleep, driving performance, continuous electroencephalogram (EEG), sleep during scheduled naps, computerized visual attention tasks, saccadic eye movement measurement and visual analogue ratings of mood. Both drugs had a marked suppressive effect on nocturnal rapid eye movement (REM) sleep; these effects were less at 36 days than at 10 days, and fluoxetine decreased and dothiepin increased REM in daytime naps. Sleep fragmentation after fluoxetine is similar to that reported in the literature. We found no sleep-promoting effects of dothiepin, in contrast to our previous single-dose study, and no subjective sleep effects of either drug. Subjects were less sleepy after both antidepressants than placebo at 5 weeks measured by sleep latencies and EEG. Saccadic eye movement measures were significantly faster after 5 weeks of fluoxetine than after 5 weeks of placebo. Reaction times to a peripheral stimulus during computerized tracking task were shorter after 10 days of dothiepin compared with placebo. Driving performance, visual attention and mood ratings showed no treatment effects. Subjective health reports during each 5 weeks of treatment were similar in number for the two drugs but showed a different profile of side-effects.

Adrenergic Uptake Inhibitors↗
PubMed2004

PC-based high-speed video-oculography for measuring rapid eye movements in mice.

We newly developed an infrared video-oculographic system for on-line tracking of the eye position in awake and head-fixed mice, with high temporal resolution (240 Hz). The system consists of a commercially available high-speed CCD camera and an image processing software written in LabVIEW run on IBM-PC with a plug-in video grabber board. This software calculates the center and area of the pupil by fitting circular function to the pupil boundary, and allows robust and stable tracking of the eye position in small animals like mice. On-line calculation is performed to obtain reasonable circular fitting of the pupil boundary even if a part of the pupil is covered with shadows or occluded by eyelids or corneal reflections. The pupil position in the 2-D video plane is converted to the rotation angle of the eyeball by estimating its rotation center based on the anatomical eyeball model. By this recording system, it is possible to perform quantitative analysis of rapid eye movements such as saccades in mice. This will provide a powerful tool for analyzing molecular basis of oculomotor and cognitive functions by using various lines of mutant mice.

Animals↗