Presbycusis and the Aging of Eye Movement: Common Attention Mechanisms

Presbycusis, physiological age-related hearing loss, is a major health problem because it is the most common cause of hearing impairment, and its impact will grow in the coming years with the aging population. Besides auditory consequences, the literature recently found an association between hearing loss and cognitive decline over the last two decades, emphasizing the importance of the early detection of presbycusis. However, the current hearing tests are not sufficient to detect presbycusis in some cases. Furthermore, the underlying mechanisms of this association are still under discussion, calling for a new field of research on that topic. In that context, this study investigates for the first time the interaction between presbycusis, eye movement latency and Stroop scores for a normal aging population. Hearing abilities, eye movement latency and the Stroop Victoria test were measured for 69 elderly (mean 66.7 ± 8.4) and 30 young (mean 25.3 ± 2.7) participants. The results indicated a significant relationship between saccade latency and speech audiometry in the silence score, independently from age. These promising results suggest common attentional mechanisms between speech processing and saccade latency. The results are discussed regarding the relationship between hearing and cognition, and regarding the perspective of expanding new tools for presbycusis diagnosis.

Differences on Prosaccade Task in Skilled and Less Skilled Female Adolescent Soccer Players

Although the relationship between cognitive processes and saccadic eye movements has been outlined, the relationship between specific cognitive processes underlying saccadic eye movements and skill level of soccer players remains unclear. Present study used the prosaccade task as a tool to investigate the difference in saccadic eye movements in skilled and less skilled Chinese female adolescent soccer players. Fifty-six healthy female adolescent soccer players (range: 14–18years, mean age: 16.5years) from Fujian Youth Football Training Base (Fujian Province, China) took part in the experiment. In the prosaccade task, participants were instructed to fixate at the cross at the center of the screen as long as the target appeared peripherally. They were told to saccade to the target as quickly and accurately as possible once it appeared. The results indicated that skilled soccer players exhibited shorter saccade latency (p=0.031), decreased variability of saccade latency (p=0.013), and higher spatial accuracy of saccade (p=0.032) than their less skilled counterparts. The shorter saccade latency and decreased variability of saccade latency may imply that the attentional system of skilled soccer player is superior which leads to smaller attention fluctuation and less attentional lapse. Additionally, higher spatial accuracy of saccade may imply potential structural differences in brain underlying saccadic eye movement between skilled and less skilled soccer players. More importantly, the results of the present study demonstrated that soccer players’ cognitive capacities vary as a function of their skill levels. The limitations of the present study and future directions of research were discussed.

EXPRESS: The unique role of novel linguistic labels on the disengagement of visual attention

Do novel linguistic labels have privileged access to attentional resources compared to non-linguistic labels? This study explores this possibility through two experiments with a training and an attentional overlap task. Experiment 1 investigates how novel label and object-only stimuli influence resource allocation and disengagement of visual attention. Experiment 2 tests the impact of linguistic information on visual attention by comparing novel tones and labels. Because disengagement of attention is affected both by the saliency of the perceptual stimulus and by the degree of familiarity with the stimulus to be disengaged from, we compared pupil size variations and saccade latency under different test conditions: (i) consistent with (i.e., identical to) the training; (ii) inconsistent with the training (i.e., with an altered feature), and (iii) deprived of one feature only in Experiment 1. Experiment 1 indicated a general consistency advantage (and deprived disadvantage) driven by linguistic label-object pairs compared to object-only stimuli. Experiment 2 revealed that tone-object pairs led to higher pupil dilation and longer saccade latency than linguistic label-object pairs. Our results suggest that novel linguistic labels preferentially impact the early orienting of attention.

Reflexive and Intentional Saccadic Eye Movements in Migraineurs

Background: Migraine has been postulated to lead to structural and functional changes of different cortical and subcortical areas, including the frontal lobe, the brainstem, and cerebellum. The (sub-)clinical impact of these changes is a matter of debate. The spectrum of possible clinical differences include domains such as cognition but also coordination. The present study investigated the oculomotor performance of patients with migraine with and without aura compared to control subjects without migraine in reflexive saccades, but also in intentional saccades, which involve cerebellar as well as cortical networks.Methods: In 18 patients with migraine with aura and 21 patients with migraine without aura saccadic eye movements were recorded in two reflexive (gap, overlap) and two intentional (anti, memory) paradigms and compared to 25 controls without migraine.Results: The main finding of the study was an increase of saccade latency in patients with and without aura compared to the control group solely in the anti-task. No deficits were found in the execution of reflexive saccades.Conclusions: Our results suggest a specific deficit in the generation of correct anti-saccades, such as vector inversion. Such processes are considered to need cortical networks to be executed correctly. The parietal cortex has been suggested to be involved in vector inversion processes but is not commonly described to be altered in migraine patients. It could be discussed that the cerebellum, which is recently thought to be involved in the pathophysiology of migraine, might be involved in distinct processes such as spatial re-mapping through known interconnections with parietal and frontal cortical areas.

Pupillary aperture is a potential biomarker of movement preparation

ABSTRACTIn response to variable light intensity, the pupils reflexively constrict or dilate to maintain a uniform retinal illumination. The pupillary light reflex (PLR) pathway receives projections from two important areas in primates’ brain that plan rapid saccadic eye-movement – frontal eye field (FEF) and superior colliculus (SC). The speed with which neurons in these areas increase firing rate to a threshold determines latency of a saccade. Micro-stimulation of FEF/SC neurons below this threshold modulates the magnitude of PLR. Nonetheless, how the saccade latency and pupil dynamics are related remains unknown. Our study shows that the appearance of a bright stimulus evokes pupil constriction at higher rate when the latency of impending saccade to the stimulus is shorter. This inverse relationship between the rate of pupil constriction and the saccade latency is robust irrespective of the reward outcome. In a homeomorphic biomechanical model of pupil, we have projected build-up signal similar to FEF and SC activity to the parasympathetic and sympathetic divisions of the PLR pathway, respectively. Model simulation mimics the observed data to indicate that the FEF and SC activity for eye movement modulates autonomic input to the pupillary muscle plant. A striking similarity between the dynamics of pupil constriction and stochastic rise in neural activity for saccade elicitation suggests that PLR is a potential proxy of movement preparation, and not mere an indicator of attentional orientation. Our study suggests a mechanism of how the retinal luminosity is timely regulated to aid perception by minimizing visual transients due to gaze orientation.

Computerized Eye-Tracking Training Improves the Saccadic Eye Movements of Children with Attention-Deficit/Hyperactivity Disorder

Abnormal saccadic eye movements, such as longer anti-saccade latency and lower pro-saccade accuracy, are common in children with attention-deficit/hyperactivity disorder (ADHD). The present study aimed to investigate the effectiveness of computerized eye-tracking training on improving saccadic eye movements in children with ADHD. Eighteen children with ADHD (mean age = 8.8 years, 10 males) were recruited and assigned to either the experimental (n = 9) or control group (n = 9). The experimental group underwent an accumulated 240 min of eye-tracking training within two weeks, whereas the control group engaged in web game playing for the same amount of time. Saccadic performances were assessed using the anti- and pro-saccade tasks before and after training. Compared to the baseline, only the children who underwent the eye-tracking training showed significant improvements in saccade latency and accuracy in the anti- and pro-saccade tasks, respectively. In contrast, the control group exhibited no significant changes. These preliminary findings support the use of eye-tracking training as a safe non-pharmacological intervention for improving the saccadic eye movements of children with ADHD.

Saccadic eye movements in dual tasking: No impairment of spatial planning, but delayed execution of saccades

In the target–distractor saccade task, a target and an irrelevant distractor are simultaneously presented and the task itself consists of a target-directed saccade. Findings usually show that as saccade latency increases, saccade trajectory deviation towards the distractor decreases. We presented this saccade task in two dual-task experiments to address the open question of whether performance of an auditory–manual task simply delays the temporal execution of a saccade, or whether it also interferes with the spatial planning of the saccade trajectory. We measured saccade latency, as a measure of a delay in execution, and saccade trajectory deviation, as a measure of the spatial planning. In Experiment 1, the auditory–manual task was a two-choice reaction time (two-CRT) task, and in Experiment 2, it was a go-no-go task. Performing the two tasks in close temporal succession shortly delayed the temporal execution of the saccade, but did not influence the spatial planning of the saccade trajectory. This result pattern was more pronounced when the auditory–manual task required the selection and execution of one of two possible manual responses (Experiment 1), less pronounced when the auditory–manual task required the decision to execute a button press (go condition, Experiment 2), and absent when the auditory–manual task required the decision to inhibit a button press (no-go condition, Experiment 2). Taken together, the manual response rather than the response selection process of the auditory–manual task led to a delay of saccade execution, but not to an impairment of the spatial planning of the saccade trajectory.

To look or not to look: Subliminal abrupt-onset cues influence constrained free-choice saccades

Subliminal cues have been shown to capture attention and modulate manual response behaviour but their impact on eye movement behaviour is not well-studied. In two experiments, we examined if subliminal cues influence constrained free-choice saccades and if this influence is under strategic control as a function of task-relevancy of the cues. On each trial, a display containing four filled circles at the centre of each quadrant was shown. A central coloured circle indicated the relevant visual field on each trial (Up or Down in Experiment 1; Left or Right in Experiment 2). Next, abrupt-onset cues were presented for 16 ms at one of the four locations. Participants were then asked to freely choose and make a saccade to one of the two target circles in the relevant visual field. The analysis of the frequency of saccades, saccade endpoint deviation and saccade latency revealed a significant influence of the relevant subliminal cues on saccadic decisions. Latency data showed reduced capture by spatially-irrelevant cues under some conditions. These results indicate that spatial attentional control settings as defined in our study could modulate the influence of subliminal abrupt-onset cues on eye movement behaviour. We situate the findings of this study in the attention-capture debate and discuss the implications for the subliminal cueing literature.

Normative Values of Saccades and Smooth Pursuit in Children Aged 5 to 17 Years

Background Pediatric oculomotor function can be evaluated via videonystagmography. Adult normative data for saccades and smooth pursuit tests cannot be used as a benchmark for pediatric patients because children's peripheral and central systems continue to mature throughout adolescence. Purpose The purpose of this study was to establish normative data for saccade and smooth pursuit tests that can be used clinically in the assessment of vestibular and neurological disorders in children, and to investigate the effect of age and eye movement direction (left/right) on tests parameters. Research Design The present study is prospective cross-sectional study. Study Sample A total of 120 healthy children were recruited and equally distributed according to age and gender to each of the following groups: 5-8, 9-11, 12-14, and 15-17 years old. Participants had to pass a comprehensive otological and neurological assessment prior to inclusion in the study. Each subject underwent saccade and smooth pursuit testing. Data Collection and Analysis Saccade latency, velocity and accuracy/precision, and smooth pursuit gain were analyzed across groups using a two-way repeated measure multivariate analysis of variance (MANOVA). Results Saccadic latency was longer in the youngest group aged 5-8 years old (305 ± 48 msec) in comparison to children aged 9-11 years old (276 ± 22 msec) (P = 0.017), 12-14 years old (252 ± 34 msec) (P = 0.001) adolescents 15-17 years (256 ± 33 msec) (P = 0.001). Age did not affect the results of saccadic velocity and accuracy/precision. Saccade parameters (latency, velocity, accuracy/ precision) were not affected by oculomotor direction (left vs. right). Smooth pursuit gain increased from 0.63 in children aged 5-8 years old to 0.85 in children aged 15-17 years (P = 0.0001). The percentage of gain asymmetry was significantly different in the youngest two groups. Conclusion Saccade latency decreased as age increased. Smooth pursuit gains increased with increased age. Saccade velocity and accuracy/precision did not change significantly from ages 5-8 to 15-17 years of age. These data provide normative values for pediatric oculomotor evaluation and suggest that saccade and pursuit pathways may mature at different rates.