Abstract W P140: Post-stroke Oculomotor Abnormalities evident during Objective Eye Tracking but Not under Clinical Assessment

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
John-Ross Rizzo ◽  
Todd Hudson ◽  
Briana Kowal ◽  
Michal Wiseman ◽  
Preeti Raghavan
Keyword(s):  
Motor Control ◽  
Eye Movements ◽  
Eye Movement ◽  
Oculomotor Control ◽  
Healthy Controls ◽  
Visually Guided ◽  
Stroke Patients ◽  
Movement Execution ◽  
Post Stroke ◽  
Control Post

Introduction: Visual abnormalities and manual motor control have been studied extensively after stroke, but an understanding of oculomotor control post-stroke has not. Recent studies have revealed that in visually guided reaches arm movements are planned during eye movement execution, which may contribute to increased task complexity. In fact, in healthy controls during visually guided reaches, the onset of eye movement is delayed, its velocity reduced, and endpoint errors are larger relative to isolated eye movements. Our objective in this experiment was to examine the temporal properties of eye movement execution for stroke patients with no diagnosed visual impairment. The goal is to improve understanding of oculomotor control in stroke relative to normal function, and ultimately further understand its coordination with manual motor control during joint eye and hand movements. We hypothesized that stroke patients would show abnormal initiation or onset latency for saccades made in an eye movement task, as compared to healthy controls. Methods: We measured the kinematics of eye movements during point-to-point saccades; there was an initial static, fixation point and the stimulus was a flashed target on a computer monitor. We used a video-based eye tracker for objective recording of the eye at a sampling frequency of 2000 Hz (SR Research, Eyelink). 10 stroke subjects, over 4 months from injury and with no diagnosed visual impairment, and 10 healthy controls completed 432 saccades in a serial fashion. Results: Stroke patients had significantly faster onset latencies as compared to healthy controls during saccades (99.5ms vs. 245.2ms, p=0.00058). Conclusion: A better understanding of the variations in oculomotor control post-stroke, which may go unnoticed during clinical assessment, may improve understanding of how eye control synchronizes with arm or manual motor control. This knowledge could assist in tailoring rehabilitative strategies to amplify motor recovery. For next steps, we will perform objective eye and hand recordings during visually guided reaches post-stroke to better understand the harmonization or lack thereof after neurologic insult.

Visually guided saccade versus eye-hand reach: contrasting neuronal activity in the cortical supplementary and frontal eye fields

1996 ◽  
Vol 75 (5) ◽  
pp. 2187-2191 ◽  
Author(s):  
H. Mushiake ◽  
N. Fujii ◽  
J. Tanji
Keyword(s):  
Eye Movement ◽  
Neuronal Activity ◽  
Motor Task ◽  
Oculomotor Control ◽  
Frontal Eye Field ◽  
Frontal Eye Fields ◽  
Saccadic Eye Movement ◽  
Visually Guided ◽  
Supplementary Eye Field ◽  
Eye Field

1. We studied neuronal activity in the supplementary eye field (SEF) and frontal eye field (FEF) of a monkey during performance of a conditional motor task that required capturing of a target either with a saccadic eye movement (the saccade-only condition) or with an eye-hand reach (the saccade-and-reach condition), according to visual instructions. 2. Among 106 SEF neurons that showed presaccadic activity, more than one-half of them (54%) were active preferentially under the saccade-only condition (n = 12) or under the saccade-and-reach condition (n = 45), while the remaining 49 neurons were equally active in both conditions. 3. By contrast, most (97%) of the 109 neurons in the FEF exhibited approximately equal activity in relation to saccades under the two conditions. 4. The present results suggest the possibility that SEF neurons, at least in part, are involved in signaling whether the motor task is oculomotor or combined eye-arm movements, whereas FEF neurons are mostly related to oculomotor control.

Quick phases control ocular torsion during smooth pursuit

2011 ◽  
Vol 106 (5) ◽  
pp. 2151-2166 ◽  
Author(s):  
Bernhard J. M. Hess ◽  
Jakob S. Thomassen
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Oculomotor Control ◽  
Visually Guided ◽  
Open Questions ◽  
Spatial Frequencies ◽  
Eye Rotation ◽  
Smooth Tracking

One of the open questions in oculomotor control of visually guided eye movements is whether it is possible to smoothly track a target along a curvilinear path across the visual field without changing the torsional stance of the eye. We show in an experimental study of three-dimensional eye movements in subhuman primates ( Macaca mulatta) that although the pursuit system is able to smoothly change the orbital orientation of the eye's rotation axis, the smooth ocular motion was interrupted every few hundred milliseconds by a small quick phase with amplitude <1.5° while the animal tracked a target along a circle or ellipse. Specifically, during circular pursuit of targets moving at different angular eccentricities (5°, 10°, and 15°) relative to straight ahead at spatial frequencies of 0.067 and 0.1 Hz, the torsional amplitude of the intervening quick phases was typically around 1° or smaller and changed direction for clockwise vs. counterclockwise tracking. Reverse computations of the eye rotation based on the recorded angular eye velocity showed that the quick phases facilitate the overall control of ocular orientation in the roll plane, thereby minimizing torsional disturbances of the visual field. On the basis of a detailed kinematic analysis, we suggest that quick phases during curvilinear smooth tracking serve to minimize deviations from Donders' law, which are inevitable due to the spherical configuration space of smooth eye movements.

Role of the Oculomotor Vermis in Generating Pursuit and Saccades: Effects of Microstimulation

1998 ◽  
Vol 80 (4) ◽  
pp. 2046-2062 ◽  
Author(s):  
R. J. Krauzlis ◽  
F. A. Miles
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Transition Point ◽  
Contralateral Side ◽  
Movement Behavior ◽  
Visually Guided ◽  
Ipsilateral Side ◽  
Oculomotor Vermis ◽  
Eye Velocity

Krauzlis, R. J. and F. A. Miles. Role of the oculomotor vermis in generating pursuit and saccades: effects of microstimulation. J. Neurophysiol. 80: 2046–2062, 1998. We studied the eye movements evoked by applying small amounts of current (2–50 μA) within the oculomotor vermis of two monkeys. We first compared the eye movements evoked by microstimulation applied either during maintained pursuit or during fixation. Smooth, pursuitlike changes in eye velocity caused by the microstimulation were directed toward the ipsilateral side and occurred at short latencies (10–20 ms). The amplitudes of these pursuitlike changes were larger during visually guided pursuit toward the contralateral side than during either fixation or visually guided pursuit toward the ipsilateral side. At these same sites, microstimulation also often produced abrupt, saccadelike changes in eye velocity. In contrast to the smooth changes in eye velocity, these saccadelike effects were more prevalent during fixation and during pursuit toward the ipsilateral side. The amplitude and type of evoked eye movements could also be manipulated at single sites by changing the frequency of microstimulation. Increasing the frequency of microstimulation produced increases in the amplitude of pursuitlike changes, but only up to a certain point. Beyond this point, the value of which depended on the site and whether the monkey was fixating or pursuing, further increases in stimulation frequency produced saccadelike changes of increasing amplitude. To quantify these effects, we introduced a novel method for classifying eye movements as pursuitlike or saccadelike. The results of this analysis showed that the eye movements evoked by microstimulation exhibit a distinct transition point between pursuit and saccadelike effects and that the amplitude of eye movement that corresponds to this transition point depends on the eye movement behavior of the monkey. These results are consistent with accumulating evidence that the oculomotor vermis and its associated deep cerebellar nucleus, the caudal fastigial, are involved in the control of both pursuit and saccadic eye movements. We suggest that the oculomotor vermis might accomplish this role by altering the amplitude of a motor error signal that is common to both saccades and pursuit.

scholarly journals Temporal Dynamics of Corticomuscular Coherence Reflects Alteration of the Central Mechanisms of Neural Motor Control in Post-Stroke Patients

2021 ◽  
Vol 15 ◽  
Author(s):  
Maxime Fauvet ◽  
David Gasq ◽  
Alexandre Chalard ◽  
Joseph Tisseyre ◽  
David Amarantini
Keyword(s):  
Motor Control ◽  
Healthy Subjects ◽  
Voluntary Movement ◽  
Temporal Dynamics ◽  
Elbow Extension ◽  
Stroke Patients ◽  
Post Stroke ◽  
Antagonist Muscles ◽  
Agonist And Antagonist ◽  
Agonist And Antagonist Muscles

The neural control of muscular activity during a voluntary movement implies a continuous updating of a mix of afferent and efferent information. Corticomuscular coherence (CMC) is a powerful tool to explore the interactions between the motor cortex and the muscles involved in movement realization. The comparison of the temporal dynamics of CMC between healthy subjects and post-stroke patients could provide new insights into the question of how agonist and antagonist muscles are controlled related to motor performance during active voluntary movements. We recorded scalp electroencephalography activity, electromyography signals from agonist and antagonist muscles, and upper limb kinematics in eight healthy subjects and seventeen chronic post-stroke patients during twenty repeated voluntary elbow extensions and explored whether the modulation of the temporal dynamics of CMC could contribute to motor function impairment. Concomitantly with the alteration of elbow extension kinematics in post-stroke patients, dynamic CMC analysis showed a continuous CMC in both agonist and antagonist muscles during movement and highlighted that instantaneous CMC in antagonist muscles was higher for post-stroke patients compared to controls during the acceleration phase of elbow extension movement. In relation to motor control theories, our findings suggest that CMC could be involved in the online control of voluntary movement through the continuous integration of sensorimotor information. Moreover, specific alterations of CMC in antagonist muscles could reflect central command alterations of the selectivity in post-stroke patients.

scholarly journals A method of hand motor control assessment in patients with post-stroke spasticity

2017 ◽  
Vol 31 (3) ◽  
pp. 55-70
Author(s):  
Jolanta Zwolińska ◽  
Mariusz Drużbicki ◽  
Lidia Perenc ◽  
Andrzej Kwolek
Keyword(s):  
Motor Control ◽  
Therapeutic Process ◽  
Hospital Treatment ◽  
Photometric Method ◽  
Stroke Patients ◽  
Post Stroke ◽  
Numerical Indicator ◽  
Based Medicine ◽  
Ashworth Scale ◽  
Hand Motor Control

Abstract Introduction: In order to assess hand spasticity in post-stroke patients, it is necessary to apply an objective and sensitive method which allows for characterising motor control. It is significant due to the necessity to monitor the effects of the therapeutic process according to the requirements of Evidence-Based Medicine (EBM). The aim of the study was to assess the usefulness of the measurement of pressure generated during a maximal palmar grasp and after its release for evaluating the level of hand motor control in poststroke patients compared to subjective scales. Material and methods: In order to characterise motor control, a numerical indicator calculated on the basis of the measurements of pressure generated during a maximal palmar grasp and after its release was suggested. To perform the measurements, 12 poststroke patients with hemiparesis were included in the study. In the research, the level of hand paresis was assessed with Brunnström Approach, the intensity of spasticity was graded with Modified Ashworth Scale, while hand motor function was classified with Fugl-Meyer Assessment (FMA). Pressure generated during a palmar grasp and after its release as well as palm area were measured with the use of a photometric method. The assessment was made twice, i.e. on the day of admission to the in-patient rehabilitation ward and after a three-week hospital treatment. Results: In the second measurement, a slight decrease in paresis intensity according to Brunnström Approach and lower intensity of spasticity according to Ashworth Scale were noted. A higher number of points in the FMA scale was observed. The values of the suggested indicator changed; however, in no case were these changes statistically significant. Conclusions: 1. Compared to other subjective scales, the usefulness of the measurement of pressure generated during a maximal palmar grasp and after its release for assessing the level of hand motor control in post-stroke patients was not confirmed. 2. The usefulness of the recommended method of spastic hand motor control assessment needs to be verified in further research carried out according to EBM requirements.

scholarly journals Assessment of test-retest reliability and internal consistency of the Wisconsin Gait Scale in hemiparetic post-stroke patients

2016 ◽  
Vol 30 (3) ◽  
pp. 41-53 ◽  
Author(s):  
Agnieszka Guzik ◽  
Mariusz Drużbicki ◽  
Grzegorz Przysada ◽  
Andrzej Kwolek ◽  
Agnieszka Brzozowska-Magoń ◽  
...  
Keyword(s):  
Motor Control ◽  
Internal Consistency ◽  
Lower Limb ◽  
Barthel Index ◽  
Gait Speed ◽  
Muscle Tone ◽  
Stroke Patients ◽  
Retest Reliability ◽  
Post Stroke ◽  
Test Retest Reliability

Abstract Introduction: A proper assessment of gait pattern is a significant aspect in planning the process of teaching gait in hemiparetic post-stroke patients. The Wisconsin Gait Scale (WGS) is an observational tool for assessing post-stroke patients’ gait. The aim of the study was to assess test-retest reliability and internal consistency of the WGS and examine correlations between gait assessment made with the WGS and gait speed, Brunnström scale, Ashworth’s scale and the Barthel Index. Material and methods: The research included 36 post-stroke patients. The patients’ gait was assessed with the use of the Wisconsin Gait Scale, gait speed with the use of walk test, the level of motor control in a paretic lower limb – according to Brunnström recovery stages, muscle tone in a paretic lower limb – according to modified Ashworth’s scale and functional independence was assessed using the Barthel Index. Gait was assessed with the use of the WGS twice, with a 7-day interval, by three experienced physiotherapists. Results: The analysis of internal consistency of the WGS revealed that the Cronbach’s α coefficient was high in the case of all the three raters and ranged from 0.85 to 0.88. It was noted that the coefficient of variation for all the comparisons was below 10%. When assessing the repeatability of the results, it was revealed that correlations between both measurements made by particular raters were very strong and highly significant. The WGS results significantly correlated with Brunnström scale, Ashworth’s scale and gait speed. Conclusions: It was concluded that the WGS has a high internal consistency and test-retest reliability. Also, significant correlations were found between gait assessment made with the use of the WGS and gait speed, level of motor control and muscle tone of a paretic lower limb. The WGS constitutes a promising tool for a qualitative, observational analysis of gait in post-stroke patients and allows for proper planning, monitoring and assessing rehabilitation results.

Saccade initiation and latency deficits after combined lesions of the frontal and posterior eye fields in monkeys

1992 ◽  
Vol 68 (5) ◽  
pp. 1913-1916 ◽  
Author(s):  
J. C. Lynch
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Frontal Eye Field ◽  
Visually Guided ◽  
Before And After ◽  
Combined Lesions ◽  
Eye Field ◽  
Bilateral Lesions

1. Monkeys were trained to perform horizontal visually guided saccades. Latency was measured before and after bilateral lesions of the frontal eye field (FEF) and after combined lesions of both the FEF and the posterior eye field. Destruction of either of these regions alone causes only modest deficits of eye movement, but destruction of both together produces profound oculomotor impairment. The results support the proposal that purposeful eye movements are controlled by a distributed corticocortical network that includes nodes in frontal and parieto-occipital regions.

scholarly journals Dyslexics’ Fragile Oculomotor Control Is Further Destabilized by Increased Text Difficulty

2021 ◽  
Vol 11 (8) ◽  
pp. 990
Author(s):  
Lindsey M. Ward ◽  
Zoi Kapoula
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Velocity Profiles ◽  
Reading Difficulty ◽  
Oculomotor Control ◽  
Text Difficulty ◽  
Word Decoding ◽  
Children's Book ◽  
Significant Difference ◽  
The Difference

Dyslexic adolescents demonstrate deficits in word decoding, recognition, and oculomotor coordination as compared to healthy controls. Our lab recently showed intrinsic deficits in large saccades and vergence movements with a Remobi device independent from reading. This shed new light on the field of dyslexia, as it has been debated in the literature whether the deficits in eye movements are a cause or consequence of reading difficulty. The present study investigates how these oculomotor problems are compensated for or aggravated by text difficulty. A total of 46 dyslexic and 41 non-dyslexic adolescents’ eye movements were analyzed while reading L’Alouette, a dyslexia screening test, and 35 Kilos D’Espoir, a children’s book with a reading age of 10 years. While reading the more difficult text, dyslexics made more mistakes, read slower, and made more regressive saccades; moreover, they made smaller amplitude saccades with abnormal velocity profiles (e.g., higher peak velocity but lower average velocity) and significantly higher saccade disconjugacy. While reading the simpler text, these differences persisted; however, the difference in saccade disconjugacy, although present, was no longer significant, nor was there a significant difference in the percentage of regressive saccades. We propose that intrinsic eye movement abnormalities in dyslexics such as saccade disconjugacy, abnormal velocity profiles, and cognitively associated regressive saccades can be particularly exacerbated if the reading text relies heavily on word decoding to extract meaning; increased number of regressive saccades are a manifestation of reading difficulty and not a problem of eye movement per se. These interpretations are in line with the motor theory of visual attention and our previous research describing the relationship between binocular motor control, attention, and cognition that exists outside of the field of dyslexia.

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