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Sports Medicine International Open 2024Ocular motility has been linked to Sports Concussion Assessment Tool 5 scores. However, the link between ocular motility changes and assessment result changes remains...
Ocular motility has been linked to Sports Concussion Assessment Tool 5 scores. However, the link between ocular motility changes and assessment result changes remains unclear. Hence, we investigated that potential link in patients with sports-related concussions. We retrospectively included participants aged≥18 years who were diagnosed with a sports-related concussion. They underwent smooth pursuit eye movement assessment for allocation to the good improvement (rate of fundamental frequency≥15%) or minor improvement (<15%) groups. Sports Concussion Assessment Tool 5 scores were determined at baseline and two weeks later, and score changes were compared between the groups. Thirteen men (mean±standard deviation age: 20.6±5.0 years) were included: eight (19.0±4.5 years) in the good improvement group and five (20.6±5.7 years) in the minor improvement group. Symptom number (median=2.0 vs. 0.0), symptom severity (median=22.0 vs. 3.0), single-leg stance (median=4.0 vs. 0.5), tandem stance (median=1.0 vs. 0.0), and total errors (median=5.0 vs. 0.5) were worse (all p<0.05) in the minor improvement group. Smooth pursuit eye movement improvements measured using eye-tracking technology was linked to symptom recovery in patients with sports-related concussions. Therefore, ocular motility may be an objective indicator of sports-related concussions. Future studies with more patients are needed to confirm these findings.
PubMed: 38812957
DOI: 10.1055/a-2183-1077 -
ELife May 2024In the 'double-drift' illusion, local motion within a window moving in the periphery of the visual field alters the window's perceived path. The illusion is strong even...
In the 'double-drift' illusion, local motion within a window moving in the periphery of the visual field alters the window's perceived path. The illusion is strong even when the eyes track a target whose motion matches the window so that the stimulus remains stable on the retina. This implies that the illusion involves the integration of retinal signals with non-retinal eye-movement signals. To identify where in the brain this integration occurs, we measured BOLD fMRI responses in visual cortex while subjects experienced the double-drift illusion. We then used a combination of univariate and multivariate decoding analyses to identify (1) which brain areas were sensitive to the illusion and (2) whether these brain areas contained information about the illusory stimulus trajectory. We identified a number of cortical areas that responded more strongly during the illusion than a control condition that was matched for low-level stimulus properties. Only in area hMT+ was it possible to decode the illusory trajectory. We additionally performed a number of important controls that rule out possible low-level confounds. Concurrent eye tracking confirmed that subjects accurately tracked the moving target; we were unable to decode the illusion trajectory using eye position measurements recorded during fMRI scanning, ruling out explanations based on differences in oculomotor behavior. Our results provide evidence for a perceptual representation in human visual cortex that incorporates extraretinal information.
Topics: Humans; Magnetic Resonance Imaging; Motion Perception; Female; Male; Visual Cortex; Adult; Illusions; Eye Movements; Young Adult; Photic Stimulation; Brain Mapping; Brain
PubMed: 38809774
DOI: 10.7554/eLife.76803 -
Brain and Behavior May 2024Multiple system atrophy (MSA) is a neurodegenerative disease that progresses rapidly and has a poor prognosis. This study aimed to assess the value of video oculomotor...
BACKGROUND
Multiple system atrophy (MSA) is a neurodegenerative disease that progresses rapidly and has a poor prognosis. This study aimed to assess the value of video oculomotor evaluation (VOE) in the differential diagnosis of MSA and Parkinson's disease (PD).
METHODS
In total, 28 patients with MSA, 31 patients with PD, and 30 age- and sex-matched healthy controls (HC) were screened and included in this study. The evaluation consisted of a gaze-holding test, smooth pursuit eye movement (SPEM), random saccade, and optokinetic nystagmus (OKN).
RESULTS
The MSA and PD groups had more abnormalities and decreased SPEM gain than the HC group (64.29%, 35.48%, 10%, p < .001). The SPEM gain in the MSA group was significantly lower than that in the PD group at specific frequencies. Patients with MSA and PD showed prolonged latencies in all saccade directions compared with those with HC. However, the two diseases had no significant differences in the saccade parameters. The OKN gain gradually decreased from the HC to the PD and the MSA groups (p < .05). Compared with the PD group, the gain in the MSA group was further decreased in the OKN test at 30°/s (Left, p = .010; Right p = .016). Receiver operating characteristic curves showed that the combination of oculomotor parameters with age and course of disease could aid in the differential diagnosis of patients with MSA and PD, with a sensitivity of 89.29% and a specificity of 70.97%.
CONCLUSIONS
The combination of oculomotor parameters and clinical data may aid in the differential diagnosis of MSA and PD. Furthermore, VOE is vital in the identification of neurodegenerative diseases.
Topics: Humans; Multiple System Atrophy; Parkinson Disease; Male; Diagnosis, Differential; Female; Middle Aged; Aged; Saccades; Video Recording; Nystagmus, Optokinetic; Pursuit, Smooth
PubMed: 38715394
DOI: 10.1002/brb3.3510 -
Journal of Eye Movement Research 2024Although Severe Acute Respiratory Syndrome Coronavirus 2 infection (SARS-CoV-2) is primarily recognized as a respiratory disease, mounting evidence suggests that it may...
Although Severe Acute Respiratory Syndrome Coronavirus 2 infection (SARS-CoV-2) is primarily recognized as a respiratory disease, mounting evidence suggests that it may lead to neurological and cognitive impairments. The current study used three eye-tracking tasks (free-viewing, fixation, and smooth pursuit) to assess the oculomotor functions of mild infected cases over six months with symptomatic SARS-CoV-2 infected volunteers. Fifty symptomatic SARS-CoV-2 infected, and 24 self-reported healthy controls completed the eye-tracking tasks in an initial assessment. Then, 45, and 40 symptomatic SARS-CoV-2 infected completed the tasks at 2- and 6-months post-infection, respectively. In the initial assessment, symptomatic SARS-CoV-2 infected exhibited impairments in diverse eye movement metrics. Over the six months following infection, the infected reported overall improvement in health condition, except for self-perceived mental health. The eye movement patterns in the free-viewing task shifted toward a more focal processing mode and there was no significant improvement in fixation stability among the infected. A linear discriminant analysis shows that eye movement metrics could differentiate the infected from healthy controls with an accuracy of approximately 62%, even 6 months post-infection. These findings suggest that symptomatic SARSCoV- 2 infection may result in persistent impairments in oculomotor functions, and the employment of eye-tracking technology can offer valuable insights into both the immediate and long-term effects of SARS-CoV-2 infections. Future studies should employ a more balanced research design and leverage advanced machine-learning methods to comprehensively investigate the impact of SARSCoV- 2 infection on oculomotor functions.
PubMed: 38694262
DOI: 10.16910/jemr.17.1.2 -
RSC Advances Apr 2024The corrosion of metals is still a huge challenge for various industries, and the pursuit of effective treatments ensures environmental sustainability. In this study, we...
The corrosion of metals is still a huge challenge for various industries, and the pursuit of effective treatments ensures environmental sustainability. In this study, we utilized banana sap-water extract (BSWE) to prevent mild steel from electrochemical corrosion in a 0.1 M HCl at room temperature. Corrosion resistance was assessed using various electrochemical methodologies, combining with surface characterization techniques. The results showed a high level of effectiveness when the corrosion current density decreased from 3292.67 μA cm (for the sample immerged in the blank solution) to 187.33 μA cm after 24 hours of immersion in the solution containing BSWE at a 2000 ppm concentration, equivalent to corrosion efficiency of 94.32%. Surface characterization revealed diminished corrosion on the inhibited steel surface due to the formation of a protective layer. X-ray photoelectron spectroscopy results demonstrated the presence of BSWE ingredients combining with iron oxides and hydroxides to form a smooth protective layer. Furthermore, theoretical calculations also indicated that the addition of BSWE can reduce steel surface damage when exposing to corrosive environment. The inhibitor based on banana sap extract can be referred to as a sustainable protective coating since it is biodegradable, abundantly available in banana plants and free of other harmful substances.
PubMed: 38690114
DOI: 10.1039/d4ra00132j -
The British and Irish Orthoptic Journal 2024A narrative review of the literature reporting ocular abnormalities in patients with schizophrenia was undertaken to determine the types and prevalence of orthoptic... (Review)
Review
PURPOSE
A narrative review of the literature reporting ocular abnormalities in patients with schizophrenia was undertaken to determine the types and prevalence of orthoptic conditions in this patient cohort.
METHODS
A systematic search of multiple databases yielded 1,974 studies published between January 1992 and January 2022. All were screened for relevance based on their title and abstract.
RESULTS
Seventeen studies were included in the final review. Ocular abnormalities reported in schizophrenia included a high incidence of strabismus, reduced visual acuity and reduced stereopsis compared to controls. Additionally, eye movement abnormalities (including reduced smooth pursuit gain and increased prosaccade latency) were frequently reported. Reduced visual acuity was associated with negative symptoms and reduced quality of life in schizophrenia.
CONCLUSIONS
Orthoptists and eye care professionals should be aware that a higher incidence of strabismus, reduced visual acuity, reduced stereoacuity, and eye movement abnormalities are reported in patients with schizophrenia. Further research is required to determine whether, or to what extent, ocular abnormalities and visual disturbances influence or exacerbate the symptoms of schizophrenia, and whether there is an effect of schizophrenia medication on these orthoptic conditions.
PubMed: 38681187
DOI: 10.22599/bioj.327 -
Eye and Brain 2024This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD),... (Review)
Review
This review delineates the ocular motor disturbances across a spectrum of neurodegenerative disorders, including Alzheimer's Disease (AD) and related disorders (ADRD), Parkinson's Disease (PD), atypical parkinsonism, and others, leveraging advancements in eye-tracking technology for enhanced diagnostic precision. We delve into the different classes of eye movements, their clinical assessment, and specific abnormalities manifesting in these diseases, highlighting the nuanced differences and shared patterns. For instance, AD and ADRD are characterized by increased saccadic latencies and instability in fixation, while PD features saccadic hypometria and mild smooth pursuit impairments. Atypical parkinsonism, notably Progressive Supranuclear Palsy (PSP) and Corticobasal Syndrome (CBS), presents with distinct ocular motor signatures such as vertical supranuclear gaze palsy and saccadic apraxia, respectively. Our review underscores the diagnostic value of eye movement analysis in differentiating between these disorders and also posits the existence of underlying common pathological mechanisms. We discuss how eye movements have potential as biomarkers for neurodegenerative diseases but also some of the existing limitations.
PubMed: 38617403
DOI: 10.2147/EB.S384769 -
Neuropsychologia Jul 2024Left smooth pursuit eye movement training in response to large-field visual motion (optokinetic stimulation) has become a promising rehabilitation method in left spatial...
Left smooth pursuit eye movement training in response to large-field visual motion (optokinetic stimulation) has become a promising rehabilitation method in left spatial inattention or neglect. The mechanisms underlying the therapeutic effect, however, remain unknown. During optokinetic stimulation, there is an error in visual localisation ahead of the line of sight. This could indicate a change in the brain's estimate of one's own direction of gaze. We hypothesized that optokinetic stimulation changes the brain's estimate of gaze. Because this estimate is critical for coding the locus of attention in the visual space relative to the body and across sensory modalities, its change might underlie the change in spatial attention. Here, we report that in healthy participants optokinetic stimulation causes not only a directional bias in the proprioceptive signal from the extraocular muscles, but also a corresponding shift of the locus of attention. Both changes outlasted the period of stimulation. This result forms a step in investigating a causal link between the adaptation in the sensorimotor gaze signals and the recovery in spatial neglect.
Topics: Humans; Attention; Male; Perceptual Disorders; Female; Adult; Fixation, Ocular; Photic Stimulation; Space Perception; Young Adult; Motion Perception; Proprioception; Pursuit, Smooth
PubMed: 38599567
DOI: 10.1016/j.neuropsychologia.2024.108883 -
Journal of Eye Movement Research 2023This study investigates the change in horizontal saccadic eye movement and smooth pursuit in patients with acquired comitant esotropia (ACE), before and after strabismus...
This study investigates the change in horizontal saccadic eye movement and smooth pursuit in patients with acquired comitant esotropia (ACE), before and after strabismus surgery. The horizontal saccades and pursuit in 11 patients with ACE were recorded using a video eye-tracker under binocular viewing before and after strabismus surgery. Participants were instructed to fixate on the new target as rapidly as possible when it randomly appeared at either 18.3° rightward or 18.3° leftward. For smooth pursuit, participants were asked to track, as accurately as possible, a step-ramp target moving at ±6.1°/s. The asymmetry of adduction-abduction and the binocular coordination in gains of saccade and pursuit were compared between the pre- and post-surgical data. The asymmetry of adduction-abduction saccade gain in each eye after surgery tended to be smaller than that before surgery. The binocular coordination of saccade showed significant improvement after surgery in only the non-dominant eye direction. Adduction-abduction asymmetry in the smooth pursuit gain in each eye after surgery tended to be smaller than before surgery. After surgery, the binocular coordination of pursuit was improved significantly in both directions. In patients with ACE, binocular coordination of saccade and smooth pursuit was poor. Binocular coordination of saccade and pursuit seems to be improved due to the improvement in ocular deviation angle and binocular visual function after surgery.
PubMed: 38567314
DOI: 10.16910/jemr.16.4.3 -
Journal of Vision Apr 2024The sudden onset of a visual object or event elicits an inhibition of eye movements at latencies approaching the minimum delay of visuomotor conductance in the brain....
The sudden onset of a visual object or event elicits an inhibition of eye movements at latencies approaching the minimum delay of visuomotor conductance in the brain. Typically, information presented via multiple sensory modalities, such as sound and vision, evokes stronger and more robust responses than unisensory information. Whether and how multisensory information affects ultra-short latency oculomotor inhibition is unknown. In two experiments, we investigate smooth pursuit and saccadic inhibition in response to multisensory distractors. Observers tracked a horizontally moving dot and were interrupted by an unpredictable visual, auditory, or audiovisual distractor. Distractors elicited a transient inhibition of pursuit eye velocity and catch-up saccade rate within ∼100 ms of their onset. Audiovisual distractors evoked stronger oculomotor inhibition than visual- or auditory-only distractors, indicating multisensory response enhancement. Multisensory response enhancement magnitudes were equal to the linear sum of responses to component stimuli. These results demonstrate that multisensory information affects eye movements even at ultra-short latencies, establishing a lower time boundary for multisensory-guided behavior. We conclude that oculomotor circuits must have privileged access to sensory information from multiple modalities, presumably via a fast, subcortical pathway.
Topics: Humans; Reaction Time; Pursuit, Smooth; Brain; Saccades; Memory; Photic Stimulation
PubMed: 38558158
DOI: 10.1167/jov.24.4.3