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Lateral eye movement while eyes are closed.

The present study was designed (1) to clarify whether lateral eye movements appear when eyes are closed as well as when they are open and (2) to examine some possible factors which may affect the phenomenon. Horizontal eye movements of 8 males and 8 females during reflection were recorded by means of electro-oculography. All the subjects showed fewer lateral eye movements in eyes-closed condition than in eyes-open condition, and neither the consistency of direction nor the effect of question types was replicated. These facts cannot be explained by the hemispheric activation hypothesis.

Dominance, Cerebral↗

Searching eye movement, smooth pursuit eye movement and schizophrenia.

OBJECTIVE: To detect whether the smooth pursuit eye movement (SPEM) and searching eye movement (SEM) could be considered as a biological marker of schizophrenia, and used as a tool in helping diagnosis of schizophrenia. METHODS: 88 schizophrenics, 77 patients with mood disorders, 32 with "neurosis", and 74 normal healthy controls were examined for SPEM and SEM individually. The authors verified the results in all the first-visit 150 outpatients in March 1993 by comparing the examination results with the clinical diagnoses after a 6-month follow-up. RESULTS: Significant differences were found in the number of eye fixation (NEF) and total eye scanning length (TESL) of SEM between schizophrenics and normal controls or patients with other disorders. Less NEF and shorter TESL could be helpful in differential diagnosis, and the agreement rate, Kappa coefficient was 0.62. No significant differences were found in SPEM in this investigation between non-medicated schizophrenics and normal controls. CONCLUSION: Searching eye movement (SEM) might be considered as a biological marker of schizophrenia and might be used as a supplementary tool in its diagnosis.

Adult↗

Smooth pursuit eye movements and saccadic eye movements in patients with delusional disorder.

OBJECTIVE: This study used eye movement tests to examine whether frontal lobe dysfunction is present in delusional disorder. METHOD: Smooth pursuit and voluntary saccadic eye movements of 15 delusional patients, 40 schizophrenic patients, and 40 normal subjects were recorded and analyzed statistically. RESULTS: The schizophrenic patients differed significantly from the normal subjects in some smooth pursuit eye movement characteristics, whereas both the schizophrenic and the delusional patients showed more saccades than the normal subjects during the smooth pursuit test. The delusional patients and normal subjects differed significantly in some voluntary saccadic eye movement characteristics. CONCLUSIONS: The data support the idea of a biological dysfunction in eye tracking in delusional disorder.

Adult↗

Effects of light and dark environments on macaque and human fixational eye movements.

Eye position of two macaques and two humans was recorded while they detected the unpredictable dimming of a fixation spot in a dark or a light environment. Fixational saccades often had complex waveforms that resulted from clustering of two or more saccadic displacements with no intervening drift periods. In the dark, all subjects had low frequencies of saccade clusters (0.15-0.61/sec). Three of the subjects increased the frequency of saccade clusters and decreased the magnitude of the displacements when the task was performed in the normally lighted laboratory. The higher saccade frequencies in the light did not automatically result in greater dispersion of eye position. One of the humans, who had the lowest saccade frequency, was relatively unaffected by the stimulus conditions. The change in stimulus conditions had a more pronounced effect on the fixational eye movements of the macaques than the humans. In the dark, the macaques made saccades mostly down and nasal, but in the light the saccadic displacements occurred over a wider range of angular directions. Mean eye position was higher in the dark than in the light. The humans altered the direction of their saccadic displacements very little and did not change their mean eye position when they switched from a dark to a lighted environment. The influence of a lighted environment is interpreted as an interaction between foveolar and peripheral retinal inputs. The results suggest that fixational saccades may have more than one role, perhaps including stimulation of pathways originating in the peripheral retina. These peripheral field inputs have a stronger effect on the fixational control system of macaques than of humans.

Adult↗

Disorders of eye movements.

Eye movements serve the needs of our visual sense and can be classified into subtypes according to their specific functions. Main functions and dysfunctions are given, with an emphasis on nystagmus.

Abducens Nerve↗

Lexical control of within-word eye movements.

Eye movements were recorded during the reading of long words, which were presented in isolation at their optimal viewing position. Refixations were found to be preferentially directed toward the region of the word that contained the critical letters for distinguishing it from its competitors. In Experiments 1 and 2, low-frequency stimulus words sharing all letters except the initial ones with a high-frequency stimulus word (critical letters at the beginning of the word) elicited more left refixations than low-frequency stimulus words sharing all letters except the final ones with a high-frequency stimulus word (critical letters at the end of the word). A similar result was found in Experiments 3 and 4, using an orthographic priming paradigm. These results suggest that refixations are linked to the selection stage of lexical access, aimed at isolating a single lexical entry among a set of candidates activated during the first fixation.

Adult↗

Induced rotary movement during eye movements: displays with unequal spacing of pattern.

In my previous (Reinhardt-Rutland, 1982) study, I suggested that eye movements enhance induced rotary movement. However, low salience of absolute displacement might also explain the results, as displays were covered with large numbers of equally spaced radial pattern elements. To test these competing hypotheses in the present study, I used an unequally spaced pattern in two displays. Common to each display was an annulus: In one display, the common annulus surrounded a disk, and in the other display the common annulus was surrounded by another annulus. In any trial, one component rotated and the other was stationary while for 40 s the subject's eyes followed a circular path concentric with the display; subjects timed those occasions when perceived stronger rotation resided in the common annulus. Despite an unequally spaced pattern, absolute displacement had a barely significant effect. Instead, perceived stronger rotation mostly resided in a display's more central component. I concluded therefore that eye movements enhance induced rotary movement.

Adult↗

The vestibulo-ocular reflex during human saccadic eye movements.

Eye and head movements were recorded in normal humans during rapid refixations with the head still (saccades) or moving (gaze saccades) to determine if the vestibulo-ocular reflex was operating at such times. Subjects made self-electrooculogram for large saccades and with the eyecoil/magnetic field method for smaller movements. The putative function of the vestibulo-ocular reflex during a gaze saccade is to adjust the movement of the eye for the movement of the head by adding the saccadic command and the vestibular signal. This action, referred to here as linear summation, would maintain gaze-saccade accuracy by making gaze velocity (eye in space) independent of head velocity. It would also preserve the duration of the eye saccades of about 200 deg. When a subject increased his head velocity voluntarily, for example, from 420 to 805 deg/s, mean gaze velocity rose from 540 to 820 deg/s and duration dropped from 380 to 250 ms. Linear summation did not occur. By means of a yoke clenched in the teeth, the subject's head could be momentarily and unexpectedly slowed by collision of the yoke with a lead weight during a 180 deg gaze saccade. The perturbation decreased head velocity by about 150-200 deg/s, decreased gaze velocity by about the same amount and did not change eye velocity (in the head); another indication that the vestibulo-ocular reflex was not working. Nevertheless, gaze-saccade duration was automatically increased so that the over-all accuracy of the movement was not changed. Subjects made saccades between targets at +/- 20 deg without attempted head movements. Simultaneously the experimenter struck the yoke, clenched in the subject's teeth, with a rubber hammer. The hammer blow caused a transient head velocity of about 70 deg/s. Gaze velocity transiently rose or fell, depending on the direction of the blow, by similar amounts and a quantitative analysis suggested that the vestibulo-ocular reflex was essentially absent. Again, duration was automatically altered so that saccade accuracy was not changed. Subjects looked back and forth between targets 20, 40 and 60 deg apart as their head turned through the straight ahead position, actively or passively, at velocities up to 600 deg/s (active) or 300 deg/s (passive).(ABSTRACT TRUNCATED AT 400 WORDS)

Eye Movements↗

Functional neuroanatomical correlates of eye movements during rapid eye movement sleep in depressed patients.

In depressed patients, REM density, or the number of rapid eye movements (REMs) per minute of REM sleep, is a correlate of depression severity and clinical outcomes. We investigated the functional neuroanatomical correlates of average REM counts (RC), an automated analog of REM density, in depression. Thirteen medication-free depressed patients underwent all night polysomnography and positron emission tomography (PET) scans using [(18)F]fluoro-2-deoxy-d-glucose ([(18)F] FDG) during REM sleep. Regression analyses were conducted with Statistical Parametric Mapping (SPM-99). Average RC significantly and positively correlated with relative regional cerebral metabolic rate of glucose (rCMRglc) bilaterally in the striate cortex, the posterior parietal cortices, and in the medial and ventrolateral prefrontal cortices. Average RC were negatively correlated with rCMRglc in areas corresponding bilaterally to the lateral occipital cortex, cuneus, temporal cortices, and parahippocampal gyri. The areas where average RC was positively correlated with rCMRglc appear to constitute a diffuse cortical system involved in the regulation of emotion-induced arousal. The observed pattern of correlations suggests that average RC may be a marker of hypofrontality during REM sleep in depressed patients.

Adult↗

Changes in pupillary diameter in relation to eye-movement and no-eye-movement periods in the human fetus at term.

OBJECTIVE: The aim of our study was to reveal whether pupils dilate and constrict in a time sequence in the human fetus and to assess the relationship between changes in pupillary diameter and eye-movement-no-eye-movement periods. STUDY DESIGN: We simultaneously observed pupil and eye movement with real-time ultrasonography in 30 human fetuses at 36 to 41 weeks' gestation. Eighteen were excluded because of data loss. Statistical analysis of pupillary diameter changes were made on the remaining 12 fetuses with the least median of squares regression. RESULTS: Pupillary diameters were found to be differentiated with statistical significance into two groups: 9.7% for the dilated pupil (median 3.0 mm) and 90.3% for the constricted pupil (1.7 mm). The percentage of dilated pupils during the eye-movement period (14.3%) was significantly greater than that during the no-eye-movement period (2.3%; Wilcoxon rank sum test, p < 0.0001). CONCLUSION: These findings indicate a close relation between pupillary dilatation and eye-movement periods in the human term fetus.

Eye Movements↗

[Eye movements in schizophrenia--relationships among eye movements under three experimental conditions; closed-eye, pursuit, and exploratory].

In order to investigate the pathophysiology of schizophrenia using psychophysiological indicators of eye movements, this study was conducted to clarify relations among eye movements under three experimental conditions; closed-eye, pursuit, and exploratory eye movements. Thirty-five chronic schizophrenic patients diagnosed by DSM-III-R criteria and 32 normal controls were examined. Horizontal eye movements were recorded electrooculographically with the subjects under two experimental conditions; one with eyes closed ("Closed-eye Eye Movement," Closed-eye EM), and the other with visually tracking a moving pendulum ("Pursuit Eye Movement," Pursuit EM). The closed-eye condition was further divided into two sub-conditions; one with the subjects awake and at rest, and the other with the subjects in the presence of a repetitive sound. Exploratory eye movements were recorded with an eye-mark recording system while the subjects viewing "S"-shaped geometric figures ("Exploratory Eye Movement," Exploratory EM). Indicators of eye movements under the three experimental conditions described above were measured and the correlations among them were investigated. Clinical symptoms in schizophrenics were assessed by BPRS, SANS and SADS and studied with the Factor Analysis method. In the Closed-eye EM, rapid eye movements appeared significantly more frequently and slow ones were less frequent in schizophrenics than in normals under both sub-conditions. The results for schizophrenics did not change significantly with the addition of sound stimuli. In the Pursuit EM, both the number and amplitude ratio of saccades were significantly larger in schizophrenics than in normals, although these indicators gradually decreased in both groups when tasks requiring concentration were demanded. In the Exploratory EM, the number of eye fixations, the total eye scanning length, and the "Responsive Search Score (RSS)," which is the total number of sections on which the eyes fixed during the response to the confirmative question, were all significantly smaller in schizophrenics than in normals. In schizophrenics, there were significant negative correlations between the RSS of the Exploratory EM and the number of rapid eye movements of the Closed-eye EM, the RSS and the number, amplitude ratio of saccades of the Pursuit EM, respectively. On the contrary, in normals, significant positive correlations were found between the number of rapid eye movements and the number of saccades.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Variation of electroencephalographic activity during non-rapid eye movement and rapid eye movement sleep with phase of circadian melatonin rhythm in humans.

1. The circadian pacemaker regulates the timing, structure and consolidation of human sleep. The extent to which this pacemaker affects electroencephalographic (EEG) activity during sleep remains unclear. 2. To investigate this, a total of 1.22 million power spectra were computed from EEGs recorded in seven men (total, 146 sleep episodes; 9 h 20 min each) who participated in a one-month-long protocol in which the sleep-wake cycle was desynchronized from the rhythm of plasma melatonin, which is driven by the circadian pacemaker. 3. In rapid eye movement (REM) sleep a small circadian variation in EEG activity was observed. The nadir of the circadian rhythm of alpha activity (8.25-10.5 Hz) coincided with the end of the interval during which plasma melatonin values were high, i.e. close to the crest of the REM sleep rhythm. 4. In non-REM sleep, variation in EEG activity between 0.25 and 11.5 Hz was primarily dependent on prior sleep time and only slightly affected by circadian phase, such that the lowest values coincided with the phase of melatonin secretion. 5. In the frequency range of sleep spindles, high-amplitude circadian rhythms with opposite phase positions relative to the melatonin rhythm were observed. Low-frequency sleep spindle activity (12.25-13.0 Hz) reached its crest and high-frequency sleep spindle activity (14.25-15.5 Hz) reached its nadir when sleep coincided with the phase of melatonin secretion. 6. These data indicate that the circadian pacemaker induces changes in EEG activity during REM and non-REM sleep. The changes in non-REM sleep EEG spectra are dissimilar from the spectral changes induced by sleep deprivation and exhibit a close temporal association with the melatonin rhythm and the endogenous circadian phase of sleep consolidation.

Adult↗

The organization of rapid eye movement activity during rapid eye movement sleep is impaired in the elderly.

Rapid eye movement activity (REMA) during rapid eye movement activity (REM) sleep was studied in eight elderly subjects and six young adults as a control group. Beyond global quantitative features (REMA density), we evaluated the organizational aspects of REMA, that is its occurrence in burst mode, still largely unknown in the aged. REMA density in the elderly is not significantly different than that of young adults. By contrast, the duration of REMA bursts is reduced in the elderly, as well as the 'burst state-to-burst-state' probability, i.e. the probability for successive inter-REMA time intervals to be part of the same REMA burst. These results show that global aspects of the quantitative features of REMA are preserved in the elderly, whereas their organizational aspects are impaired. These data are consistent with the hypothesis that aging is associated with a difficulty in maintaining physiological processes over time.

Adult↗

The organization of rapid eye movement activity during rapid eye movement sleep is further impaired in very old human subjects.

Rapid eye movement activity (REMA) during rapid eye movement (REM) sleep was studied in seven very old ('old-old') subjects. Beyond global quantitative features (REMA density), we evaluated the organizational aspects of REMA, that is its occurrence in burst mode, which were compared to a group of younger elderly subjects ('young-old'). REMA density in 'old-old' subjects is not significantly different from that of 'young-old' subjects. The same lack of difference in the two groups is found for the number of REMA bursts. By contrast, the duration of REMA bursts is reduced in the 'old-old' subjects, as well as the 'burst state-to-burst-state' probability, i.e. the probability for successive inter-REMA time intervals to be part of the same REMA burst. Our results clearly show that the trend towards an impairment of REMA organizational aspects continues with aging. This is consistent with the hypothesis that sleep disorganization keeps worsening with age. However, it is of interest to observe that the capability of producing REMA bursts is preserved despite aging.

Age Factors↗

Eye movement desensitization and reprocessing in the treatment of test anxiety: a study of the effects of expectancy and eye movement.

Eye Movement Desensitization and Reprocessing (EMDR) is a recently invented technique acclaimed as a major breakthrough for a range of anxiety-related symptoms. To determine the importance of the eye movement and expectancy variables, we conducted a one-hour session with 41 undergraduate subjects (11 males and 30 females) with test anxiety. A 2 (eye movement vs no eye movement) x 2 (high expectancy vs low expectancy) analysis of variance was performed on three dependent measures: (1) Subjective Units of Disturbance Scale (SUDs). (Wolpe, The Practice of Behavior Therapy, 1982); (2) Validity of Cognition Scale (VOC) (Shapiro, 1992); and (3) the Test Anxiety Inventory (TAI) (Spielberger, TestAnxiety Inventory Preliminary Professional Manual, 1977). The data indicate that all subjects, regardless of treatment condition, showed a significant decrease in anxiety on the TAI. Subjects in the eye-movement condition reported feeling less anxious (SUDs) than those in the no-eye-movement condition. We found no significant main effect or interactions for any of the dependent measures for expectancy.

Adult↗