Number Of Corrective Saccades Research Articles

Eye Motility Dysfunction in Chronic Primary Fibromyalgia With Dysesthesia

Thirty-six patients with "chronic primary fibromyalgia" combined with dysesthesia were studied using oculomotor tests. The test results were compared with those of a control group consisting of 71 healthy persons. The saccades were found to be abnormal in 42% of the patients studied. The maximum velocity of the saccades was often reduced, while the accuracy was normal. The smooth pursuit eye movements were deranged in 89% of the patients. The velocity gain was reduced and the number of corrective saccades was increased. The results indicate that brain dysfunction, often at the brainstem level, is commonly seen in patients with chronic primary fibromyalgia syndrome combined with dysesthesia.

Vestibular Dysfunction in Wernicke's Encephalopathy: Predominant Impairment of the Horizontal Semicircular Canals.

Wernicke's encephalopathy (WE), a metabolic disorder due to thiamine deficiency, manifests with various neurological symptoms and signs. It has been known as a cause of vestibular dysfunction. Preliminary reports have proposed predominant involvement of the horizontal semicircular canals (HSCs). To better characterize the pattern of vestibular impairment in patients with WE using quantitative video head-impulse testing and to review the literature regarding this topic. From January 2014 to December 2016, we retrospectively enrolled five cases of WE that received quantitative video-head-impulse testing (vHIT). We retrieved the clinical features from the medical records and reviewed quantitative head-impulse testing (qHIT) and caloric irrigation. Based on the gain and the number of corrective saccades, the function (normal vs. impaired) of each semicircular canal was rated. In addition, we conducted a MEDLINE and EMBASE search to identify other published cases of WE that had received qHIT. Neuro-otologic and neuro-ophthalmologic findings and vestibular testing results were extracted. A total of 17 patients (own series = 5; published cases = 12) aged 54.6 ± 11 years were included. Key neurologic findings were ataxia of stance and gait (13/13, 100%), spontaneous nystagmus (7/14, 50%), gaze-evoked nystagmus (GEN) (17/17, 100%), positive bedside head-impulse testing for the horizontal canals (16/17, 94%), and memory impairment and mental changes (6/11, 54.5%). Regarding vestibular testing, qHIT (either video based or search-coil based) documented selective bilateral horizontal canal dysfunction with normal or minimal vertical canal impairment (14/14, 100%). On caloric irrigation, bilateral horizontal canal paresis was noted in most cases (10/11, 91%). In WE, signs of both peripheral and central vestibular dysfunction (i.e., GEN, ataxia of stance and gait, abnormal head-impulse testing) were common. Selective or predominant impairment of the HSCs seems to be the most common finding of WE likely related to enhanced vulnerability of the medial vestibular nuclei neurons to thiamine deficiency. Quantitative vHIT of all six semicircular canals is therefore a useful tool for the diagnosis and should be applied in all patients with suspected WE.

Developmental Eye Movement Test: What is it Really Measuring?

The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool. However, while the DEM test ratio has been reported to correlate with horizontal saccadic eye movements, there have been no published comparative studies of the DEM test and objective eye movement measures. The aim of this study was to compare DEM test performance with explicit quantification of saccadic eye movements, reading performance, symptomatology and visual processing speed, to assess the validity of the DEM test in clinical practice. One hundred fifty-eight children aged 8 to 11 years completed the DEM test and a battery of eye movement tasks, recorded by a Microguide 1000 infrared eye tracker. All subjects completed a symptomatology survey. Reading performance and visual processing data was collected for 77 and 75 children, respectively. One hundred twenty-nine of the 158 subjects (81.65%) passed the DEM test. There was no significant correlation between any component of DEM test performance and quantitative eye movement parameters (gain, latency, asymptotic peak velocity, and number of corrective saccades) or symptomatology. There were significant correlations between DEM test outcome and reading performance, and with visual processing speed. DEM test performance does not correlate with saccadic eye movement skills or symptomatology. However, it is related to reading performance and visual processing speed. This study suggests that although DEM test times may not correlate directly with eye movement parameters, they do correlate with aspects of reading performance and thus may serve a diagnostic role in clinical practice.

奥行き方向の視線移動の年齢変化に関する検討

Changes in binocular eye movement occur when a subject changes his/her gaze point from a far/near to a near/far target, requiring both symmetric and asymmetric vergence. We measured these changes to investigate the effects of aging on vergence eye movement. Results indicated increases in the latency and time constants of vergence eye movement, decreases in convergence angle changes, and increases in the number of corrective saccades in subjects over 50 years, and increases in time constants in subjects below 10 years, compared with data for subjects between 10 and 50 years. This suggests that young and older subjects do not have the same vergence eye movement characteristics as those between 10 and 50 years. These differences should be considered in research about a subject's depth perception of stereoscopic images.

Effects of phosphor persistence on perception and the control of eye movements.

When a rapid eye movement (saccade) is made across material displayed on cathode ray tube monitors with short-persistence phosphors, various perceptual phenomena occur. The phenomena do not occur when the monitor has a long-persistence phosphor. These phenomena were observed for certain spatial arrays, their possible physiological basis noted, and their effect on the control of eye movements examined. When the display consisted simply of two dots, and a saccade was made from one to the other, a transient ghost image was seen just beyond the destination target. When the display consisted of vertical lines, tilting and displacement of the lines occurred. The phenomena were more intrusive for the latter display and there was a significant increase in the number of corrective saccades. These results are interpreted in terms of the effects of fluctuating illumination (and hence phosphor persistence) on saccadic suppression.