Do microsaccades vary with discriminability around the visual field?

Microsaccades-tiny fixational eye movements- improve discriminability in high acuity tasks in the foveola. To investigate whether they help compensate for low discriminability at perifovea, we examined MS characteristics relative to the adult visual performance field, which is characterized by two perceptual asymmetries: Horizontal-Vertical Anisotropy (better discrimination along the horizontal than vertical meridian), and Vertical Meridian Asymmetry (better discrimination along the lower- than upper-vertical meridian). We investigated whether and to what extent microsaccade directionality varies when stimuli are at isoeccentric locations along the cardinals under conditions of heterogeneous discriminability (Experiment 1) and homogeneous discriminability, equated by adjusting stimulus contrast (Experiment 2). Participants performed a two-alternative forced-choice orientation discrimination task. In both experiments, performance was better on trials without microsaccades between ready signal onset and stimulus offset than on trials with microsaccades. Across the trial sequence the microsaccade rate and directional pattern were similar across locations. Our results indicate that microsaccades were similar regardless of stimulus discriminability and target location, except during the response period-once the stimuli were no longer present and target location no longer uncertain-when microsaccades were biased toward the target location. Thus, this study reveals that microsaccades do not flexibly adapt as a function of varying discriminability in a basic visual task around the visual field.

The time-course of visual scanning behaviour of paramedicine students upon arrival at a simulated emergency call

BACKGROUND

Limited knowledge exists regarding how paramedics acquire an understanding of the scene they encounter upon arrival, despite their need to quickly gather information for effective clinical decision-making. This study examined visual scanning behaviour during the early stages of simulated emergency calls.

METHODS

Eye movements of 10 paramedicine students were recorded during simulated calls conducted in both a high-fidelity classroom setting and a full sensory immersion setting.

RESULTS

Students focused on similar areas in both settings, with most time spent looking at the patient rather than distractors such as room features or other people. Analysis of gaze behaviour across the first five minutes revealed a more nuanced pattern: attention initially gravitated towards distractors but decreased as students became familiar with their surroundings and focused on the task at hand. This pattern was consistent across both simulation settings, indicating that information-seeking strategies may be independent of scene complexity.

CONCLUSIONS

Expertise relies on the ability to differentiate between relevant and irrelevant information. Given the unpredictable nature of their work, paramedics must continuously adapt their understanding of a scene from the moment they enter it. Understanding how this skill develops may help identify expert strategies to inform training of novice paramedics.

Eye movements are made to the centre of gravity of texture-defined targets

Saccadic localisation of targets of various properties has been extensively studied, but rarely for texture-defined figures. In this paper, three experiments that investigate the way information from a texture target is processed in order to provide a signal for eye movement control are presented. Participants made saccades to target regions embedded in a background structure, and the saccade landing position and latency were measured. The textures comprised line elements, with orientations of the lines configured to form the figure and ground. Various orientation profile configurations (Block, Blur, and Cornsweet), were used in order to measure the role of edge profiles in driving eye movements and producing salience. We found that in all cases the visual system is in fact able to effectively segregate a texture figure from the ground in order to accurately plan a saccade to the target-figure. While saccadic latency was the highest for the Blur profile, the mean saccadic landing position was mostly unaffected by the various profiles (Experiment 1). More specifically, we showed that saccades were directed to the centre-of-gravity of the target (Experiment 2). We also found that figures with information of orientation contrast at both the edge and centre of figure (i.e. Block) produced the highest level of saliency in attracting eye movements (Experiment 3). Overall, the results show that saccades are planned on the representation of the whole target shape rather than a local salient region based on orientation contrast cues, and that the various texture profiles were important only to the extent that they affected the time to programme a saccade.

Response assignment influences visual recognition

This study investigated whether two different neural systems influenced performance in an immediate visual recognition, i.e. visual same/different task. An observer had to respond rapidly whether a test consonant had just appeared in the study string by pressing one of two response keys, labeled same and different. When the same response was assigned to the response key on the right, there was no effect of study-string position on target response time (RT), indicating that the test item was not compared with the study string. When the different response was assigned to the response key on the right, same RT was an increasing function of the left-to-right position of a target in the study string and different RT was slower than same RT, indicating that during test the study string was compared with the test item. Functional magnetic resonance imaging confirmed that the caudate and left hippocampus were more active when the different response was assigned to the right key but the right hippocampus was more active when the same response was assigned to the right key. Therefore, two different computational processes are performed by two different brain systems depending on whether the same or different response is assigned to the right response key.

Awareness of the relative quality of spatial working memory representations

Working memory (WM) is the ability to maintain and manipulate information no longer accessible in the environment. The brain maintains WM representations over delay periods in noisy population-level activation patterns, resulting in variability in WM representations across items and trials. It is established that participants can introspect aspects of the quality of WM representations, and that they can accurately compare which of several WM representations of stimulus features like orientation or color is better on each trial. However, whether this ability to evaluate and compare the quality of multiple WM representations extends to spatial WM tasks remains unknown. Here, we employed a memory-guided saccade task to test recall errors for remembered spatial locations when participants were allowed to choose the most precise representation to report. Participants remembered either one or two spatial locations over a delay and reported one item's location with a saccade. On trials with two spatial locations, participants reported either the spatial location of a randomly cued item, or the location of the stimulus they remembered best. We found a significant improvement in recall error and increase in response time (RT) when participants reported their best-remembered item compared with trials in which they were randomly cued. These results demonstrate that participants can accurately introspect the relative quality of neural WM representations for spatial position, consistent with previous observations for other stimulus features, and support a model of WM coding involving noisy representations across items and trials.

Do weak readers in rural India automatically read same language subtitles on Bollywood films? An eye gaze analysis

Same Language Subtitling (SLS) of audio-visual content on mainstream TV entertainment to improve mass reading literacy was first conceived and piloted in India. SLS is now being scaled up nationally to ensure that the reading skills of one billion TV viewers, including 600 million weak readers, remain on a lifelong pathway to practice, progress, and proficiency. Will weak readers ignore or try to read along with SLS? Our eye-tracking study investigates this question with 136 weak readers drawn from a remote village in Rajasthan state by showing them popular Hindi film clips of dialog and songs, with and without SLS. We developed an interactive web-based visual analytics tool for exploring eye-tracking data. Based on an analysis of fixations, saccades, and time spent in the subtitle and non-subtitle areas, our main finding is that 70 percent of weak readers engaged in unprompted reading while watching film clips with SLS. We observed that saccadic eye movement is a good indicator to quantify the amount of reading with SLS, and saccadic regression can further differentiate weak readers. Eye-tracking studies of weak readers watching subtitles are rare, and ours may be the first with subjects from rural India.

EXPRESS: The Effect of Sudden-Onset Distractors on Reading Efficiency and Comprehension

Reading is an essential skill that requires focused attention. However, much reading is done in non-optimal environments. These days, much reading is done on digital devices or with a digital device nearby. These devices often introduce momentary distractions during reading, interrupting with alerts, notifications, and pop-ups. In two eye-tracking experiments, we investigated how such momentary distractions impact reading. Participants read paragraphs while their eye movements were monitored. During half of the paragraphs, distractions appeared periodically on the screen that required a response from the participants. In experiment 1, the distractions were arrows that the participant had to respond to and then could immediately forget. In experiment 2, the participants performed a 1-back task that required them to remember the identity of the last distractor. Compared to the no-distraction condition, the respond-and-forget distractors of experiment 1 had minimal impact on reading behavior and comprehension, but the working-memory-load distractors of experiment 2 led to increased re-reading and decreased reading comprehension. It seems a simple pop-up does not disrupt reading, but a message you must remember will.

An unusual occurrence of opsoclonus and liver enzymes elevation in a patient with acute motor and sensory axonal neuropathy subtype of Guillain-Barré syndrome

Background

Acute motor and sensory axonal neuropathy (AMSAN) is a subtype of Guillain-Barré syndrome (GBS) differentiated by nerve conduction studies (NCS) and characterized by symmetric ascending paralysis often involving respiratory muscles. While opsoclonus, which is involuntary chaotic rapid eye movements, is not a common manifestation of GBS. Moreover, little published data are available on the relation between liver enzymes elevation and GBS.

Case presentation

A 42-year-old man presented to Al Mouwassat University Hospital with weakness in all limbs and dyspnea. Examination showed an elevated respiratory rate, hyporeflexia, and decreased strength of upper and lower limbs. Analysis of cerebrospinal fluid revealed an albuminocyto-dissociation suggesting the diagnosis of GBS and subsequent plasmapheresis. NCS confirmed a diagnosis of AMSAN. Elevation in liver enzymes was noticed prompting further exploration with no positive findings. Despite treatment efforts, the patient developed severe dyspnea, deterioration in cognitive abilities, and opsoclonus with a normal brain MRI. Unfortunately, he developed respiratory failure which lead to his death.

Conclusion

In this case, we highlight the occurrence of opsoclonus which is a rarely-encountered manifestation of GBS, in addition to an unexplained elevated liver enzyme, the thing that could contribute to larger research to further comprehend the pathophysiology of GBS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02599-0.

Oculomotor Fatigue and Neuropsychological Assessments mirror Multiple Sclerosis Fatigue

Fatigue is a major complaint in MS. Up to now no objective assessment tools have been established which hampers any treatment approach. Previous work has indicated an association of fatigue with cognitive measures of attention. Oculomotor tests have been established in healthy individuals as a read-out of fatigue, and to some extent in MS patients. Based on these observations we compared two groups of MS patients, one with fatigue (n=28) and one without fatigue (n=21) and a group of healthy subjects (n=15) with a standardised computerised measure of alertness and an oculomotor stress test. Patients with fatigue showed highly significant changes of their saccade dynamics as defined by the Main Sequence and Phase Plane plots: They showed slowing of saccades, the characteristical fatigue double peak, and an asymmetrical phase plane. Oculomotor tests differentiated significantly between fatigue and fatigabiliy in our MS patients. They also showed significantly worse performance in the alertness test as well as in the oculomotor task. Significantly slower reaction times were observed for tonic alertness in 2 series without a cue (p=.025 and p=.037) but not in phasic alertness with a cue (p=.24 and p=.34). Performance was influenced by disability as well as by affective state. We conclude, when controlling for disability and depression, saccadic stress tests and alertness tests could be used as an objective read-out for fatigability and fatigue in MS patients.

Use of Eye-Tracking in Studies of EHR Usability - The Current State: A Scoping Review

Eye-tracking has long been used to assess usability for the public web. Recently, it is used to assess user behavior with electronic health records (EHRs). We conducted a scoping review of studies involving eye-tracking for usability of EHRs to determine the current state. Three main themes emerged: studies of usual use of systems, development of new methods, and studies of new features. Detailed user behaviors revealed by eye-tracking can contribute valuable information to redesign efforts.

Relating Factors for Acceptance of Health Care Technology: Focus on Mental Workload

Medical information systems and care robots are two typical examples of human computer interaction in health care. Although used in a stressful environment, effects on mental workload and acceptance are hardly evaluated. We conducted an experimental design including collaborative robotics and eye tracking in a nursing situation to test the practicability and plausibility of eye tracking as a measuring method for workload. Results showed that eye tracking is feasible if context factors are adjusted. Data reduction and classification of tasks are necessary.

Eye gaze of endoscopists during simulated colonoscopy

Regaining orientation during an endoscopic procedure is critical. We investigated how endoscopists maintain orientation based on video and eye gaze analysis. Novices and experts performed a simulated colonoscopy procedure. Task performance was assessed by completion time, total distance traveled, maximum depth of insertion, percentage of mucosa viewed, and air insufflation volume. Procedure videos were analyzed by transfers among three viewing areas: center of bowel lumen, edge of bowel lumen, and other structure without bowel lumen in sight. Performers' gaze features were also examined over these viewing areas. Experts required less time to complete the procedure (P < 0.001). Novices' scope traveled a greater distance (P < 0.001) and more scope was inserted compared to an expert (P < 0.001). Novices also insufflated more air than experts (P < 0.001). Experts maintained the view of bowel lumen in the middle of the screen, while novices often left it on the edge (P = 0.032). When disorientation happened, novices brought the view to the edge more frequently than the center. However, experts were able to bring it back to the center directly. Eye tracking showed that the rate of saccades in experts increased when the bowel lumen moved away from the central view, such a behavior was not observed in novices. Maintaining a centered view of the bowel lumen is a strategy used by expert endoscopists. Video and eye tracking analysis revealed a key difference in eye gaze behavior when regaining orientation between novice and experienced endoscopists.

Calibration of peripheral perception of shape with and without saccadic eye movements

The cortical representations of a visual object differ radically across saccades. Several studies claim that the visual system adapts the peripheral percept to better match the subsequent foveal view. Recently, Herwig, Weiß, and Schneider (2015, Annals of the New York Academy of Sciences, 1339(1), 97-105) found that the perception of shape demonstrates a saccade-dependent learning effect. Here, we ask whether this learning actually requires saccades. We replicated Herwig et al.'s (2015) study and introduced a fixation condition. In a learning phase, participants were exposed to objects whose shape systematically changed during a saccade, or during a displacement from peripheral to foveal vision (without a saccade). In a subsequent test, objects were perceived as less (more) curved if they previously changed from more circular (triangular) in the periphery to more triangular (circular) in the fovea. Importantly, this pattern was seen both with and without saccades. We then tested whether a variable delay between the presentations of the peripheral and foveal objects would affect their association-hypothetically weakening it at longer delays. Again, we found that shape judgments depended on the changes experienced during the learning phase and that they were similar in both the saccade and fixation conditions. Surprisingly, they were not affected by the delay between the peripheral and foveal presentations over the range we tested. These results suggest that a general associative process, independent of saccade execution, contributes to the perception of shape across viewpoints.

From eyes to hands: Transfer of learning in the Simon task across motor effectors

Inhibition of irrelevant and conflicting information and responses is crucial for goal-directed behaviour and adaptive functioning. In the Simon task, for example, responses are slowed if their mappings are spatially incongruent with stimuli that must be discriminated on a nonspatial dimension. Previous work has shown that practice with incongruent spatial mappings can reduce or even reverse the Simon effect. We asked whether such practice transfers between the manual and oculomotor systems and if so to what extent this occurs across a range of behavioural tasks. In two experiments, one cohort of participants underwent anti-saccade training, during which they repeatedly inhibited the reflexive impulse to look toward a briefly presented target. Additionally, two active-control training groups were included, in which participants either trained on Pro-saccade or Fixation training regimens. In Experiment 1, we probed whether the Simon effect and another inhibitory paradigm, the Stroop task, showed differential effects after training. In Experiment 2, we included a larger battery of inhibitory tasks (Simon, Stroop, flanker and stop-signal) and noninhibitory control measures (multitasking and visual search) to assess the limits of transfer. All three training regimens led to behavioural improvements in the trained-upon task, but only the anti-saccade training group displayed benefits that transferred to the manual response modality. This transfer of training benefit replicated across the two experiments but was restricted to the Simon effect. Evidence for transfer of inhibition training across motor systems offers important insights into the nature of stimulus-response representations and their malleability.

Examining Eye Movements in Visual Search through Clusters of Objects in a Circular Array

Participants were asked to search for a complete O in an array consisting of eight clusters of four Landolt Cs (i.e., Os with a gap) arranged in a ring. The size of the gap in the Cs varied from cluster to cluster but was held constant within a cluster. The manual response time data were consistent with a serial self-terminating search. More importantly, eye movement data supported a serial processing model as (a) clusters were fixated serially (either clockwise or counterclockwise) on most trials and (b) fixation times on a cluster reflected processing time on that cluster and were unaffected by the gap size of either the prior or succeeding cluster. Furthermore, the pattern of fixation times on a cluster was similar to the pattern of response times in a secondary task where a single cluster was presented at fixation. These data extend the findings of Williams and Pollatsek (2007) in which search was through a linear sequence of clusters, and indicate that a serial search pattern through clusters of these kinds of objects is not confined to reading-like linear arrays.

Pelizaeus-merzbacher disease: the first genetically approved case report from iran

BACKGROUND

Classic Pelizaeus-Merzbacher disease is a rare x-linked disorder of proteolipid protein expression first described clinically in 1885. This disease is characterized by abnormal eye movements, very slow motor development and involuntary movements. The causative gene is PLP1.

CASE PRESENTATION

A 1-year-old boy was referred to our clinic due to abnormal eye movements. He had horizontal and flickering eye oscillation, psychomotor retardation, hypotonia and head nodding. We found hypomyelination in brain MRI.

CONCLUSION

The possibility of Pelizaeus-Merzbacher disease should be considered in boys with abnormal eye movements, psychomotor retardation and hypotonia.