This disease causes slowing and eventually loss of all vertical saccades. In Figure 2 , we have plotted quick-phase data from this patient and compared the results with prediction intervals of normal subjects derived from the present study. As a control, we also plotted OK quick-phase data from an age-matched patient with PD who did not have a defect of voluntary vertical saccades. It is evident that the patient with PSP has smaller, slower, and longer-duration quick phases than the control populations.
These differences are most evident on the log-scale plots, where both slope and intercept differ significantly from the fitted parameters for our normal subjects Table 1. The patient with PD was similar to control subjects. These preliminary findings indicate that OK stimulation could be used as a clinical test of the vertical saccadic system in individuals who are unable to cooperate with saccadic testing, and is the subject of an ongoing study.
In this study, the optimal stimulus to elicit OKN highest gain of slow phases was black-and-white stripes with lower spatial frequencies and lower stripe speeds 0. Although we did not specifically test smaller stimuli, a large moving visual display is known to be superior to a handheld drum. Also, our experience is that children, in particular, respond better to moving lines than random-dot patterns.
The stimuli that we used in these experiments induced responses that can be used to test both visual tracking abilities and the saccadic system by quick phases that are induced.
Submitted for publication January 22, ; revised March 3 and April 9, ; accepted April 10, Disclosure: S. Garbutt , None; Y. Han , None; A. Kumar , None; M. Harwood , None; C. Harris , None; R. Leigh , None. The publication costs of this article were defrayed in part by page charge payment. Corresponding author: R.
T able 1. View Table. T able 2. F igure 1. View Original Download Slide. Representative vertical saccadic and OKN quick-phase main sequences for duration and peak velocity.
A Scatterplot of the vertical saccadic and vertical OKN quick-phase main sequences for duration. Negative values represent eye movements downward. B Scatterplot of the vertical saccadic and vertical OKN quick-phase main sequences for peak velocity. C Logarithmic plot of duration versus amplitude upward and downward movements combined.
D Logarithmic plot of peak velocity versus amplitude upward and downward movements combined. F igure 2. Also shown are quick phases from a patient with PSP, who had difficulty making vertical saccades, and a patient with PD, who could make normal vertical saccades.
F igure 3. Upward versus downward OKN gain. Upward slow-phase velocity gain was plotted against downward slow-phase velocity gain for each subject at each stimulus speed represented by the five different colors and each spatial frequency represented by the three different shaped symbols.
Dotted line : upward gain was equal to downward gain. Points above the dotted line indicate that upward gain was greater than downward gain.
Points below the dotted line indicate that the reverse was true. T able 3. The authors thank David Riley for referring one of the patients. Robinson, DA. Oxford University Press New York. Bronstein, AM, Kennard, C. Becker, W. Pelisson, D, Prablanc, C. Takahashi, M, Igarashi, M. Matsuo, V, Cohen, B.
Vital-Durand, F, Jeannerod, M. Evinger, C, Fuchs, AF. Skrandies, W. Gibson, JJ. View Metrics. Examination of Latency, Gain, and Peak Velocity. From Other Journals Unsupervised clustering method to detect microsaccades. Analysis of human vergence dynamics. The target velocity integration function for saccades.
Task influences on the dynamic properties of fast eye movements. A dynamic representation of target motion drives predictive smooth pursuit during target blanking. Forgot password? To View More Termsarasab et al. Note: Square wave jerks are a small saccade away from and back to midline with an intersaccadic interval between movements. Macrosaccadic oscillations consist of back-to-back saccades with an intersaccadic interval between movements that oscillate in a crescendo-decrescendo pattern about the midline.
Ocular flutter refers to a similar movement in the horizontal direction only. There is no functional or clinical difference between opsoclonus and flutter.
Saccadic intrusions are spontaneous unwanted saccades during ocular fixation, and they are often provoked by gaze shifts. Multiple system atrophy: Patients can display square wave jerks and saccadic dysmetria [14]. Progressive supranuclear palsy : Square wave jerks are common. Patients have slow vertical saccades early in the course, and this precedes ophthalmoplegia [14] [15].
Opsoclonus-myoclonus ataxia syndrome: Opsoclonus is a diagnostic feature [14]. Huntington disease: The main ocular finding is impairment of saccade initiation. Patients can also have saccadic slowing and an impairment in the antisaccade task [14] [15].
Spinocerebellar ataxia : Saccades are important diagnostic clues in certain types of SCA, as slowing of saccades on horizontal gaze is a hallmark clinical feature of SCA2 [14]. Friedreich ataxia: Prominent fixation instability may cause macrosaccadic oscillations or continuous square wave jerks [14]. Oculomotor apraxia: Delayed initiation of saccades due to impaired higher cortical control.
Patients may employ head thrusts or eye blinks to generate saccades [14]. Ataxia-telangiectasia: Hypometric saccades, alternating skew deviation, and square wave jerks can be seen [14]. ADHD: Studies have shown a consistent reduction in ability to suppress unwanted saccades, suggesting an impaired functioning of areas like the dorsolateral prefrontal cortex [11].
Autism: An elevated number of antisaccade errors has been consistently reported, which may be due to disturbances in frontal cortical areas [11]. Childhood-onset schizophrenia: There is an increased number of anticipatory saccades and intrusive saccades during smooth pursuit eye movements [11]. The high accuracy of saccades in normal patients is a result of continuous adaptation [16].
Saccade adaptation involves evaluating the accuracy of past saccades and subsequently correcting the motor commands for the next saccades. Saccades are ballistic, and therefore cannot be corrected while in flight [4] , so an adaptive process is necessary to provide a greater degree of accuracy. Additionally, development and aging causes change in numerous components of the oculomotor system, such as the eye muscles, cranial nerves, and central pathways.
Saccade adaptation is unconscious and improves over repeated trials. This process is useful to correct saccade inaccuracies over time. This phenomenon is due to an entirely visual process and involves suppression of the magnocellular pathway [18] , which is involved in carrying information about motion at high velocities. Suppression of this pathway results in a greatly diminished sensitivity for motion during saccades. Create account Log in. Main page. Getting Started.
Recent changes. View form. View source. Saccade From EyeWiki. Jump to: navigation , search. Enroll in the Residents and Fellows contest. Enroll in the International Ophthalmologists contest. Residents and Fellows contest rules International Ophthalmologists contest rules. Original article contributed by :. All contributors:. Assigned editor:. Bayan Al Othman, MD. Saccades and fixations: Example of saccades and fixations while reading a sentence.
We do not move our eyes smoothly across the text. Reading consists of forward and backwards saccades and fixations. Saccades and fixations. Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. Saccade-Vergence Interactions. Sunderland MA : Sinauer Associates; Recently it has been reported that Levataceteram was helpful in a single case Eggenberger and Cherian, The author has tried many other medications -- including gabapentin and benzodiazepines -- with modest success.
Gabapentin is the most useful. As ocular flutter may be an early variant of a much more dangerous syndrome called opsoclonus see following , some caution must be exercised, if the syndrome is recent in onset. Video of opsoclonus in young woman, developed after the West Nile outbreak in Chicago. See the site DVD page for a list of more movies like this one.
Opsoclonus denotes chaotic back-back saccadic eye movements. It is a dramatic syndrome, sometimes due to cancer or a brainstem encephalitis such as West-Nile or Dengue. See this link for more information about opsoclonus. Square-Wave Jerks SWJ are inappropriate saccades that take the eye off the target, followed by a nearly normal intersaccadic interval approximately msec and then a corrective saccade that brings the eye back to the target Leigh and Zee, Saccadic intrusions are unintended saccades, not necessarily followed by a return movement as is the case for square wave jerks.
Saccadic intrusions are very common and have very little diagnostic significance. Horizontal saccadic intrusions are most commonly attributed to psychiatric disease such as schizophrenia. In the vertical and torsional planes, saccadic intrusions are instead attributed to neurological disorders. Vertical or torsional saccadic intrusions may arise from irritibility of burst neurons in the midbrain Bentley et al, Saccadic Nystagmus Timothy C.
Recording saccadic nystagmus isn't easy: Although one might think that recording of a very fast eye movement would be very easy, as it is easy to spot with the naked eye, as of , eye movement recording systems often fail to register saccadic nystagmus. This failure of many contemporary ENG clinical systems to work for this disorder is related to a combination of factors: 1. Zee, M. Ocular flutter in a normal person sawtooth waveform.
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