Visual training could be useful for improving reading capabilities in dyslexia

Background: Scanning laser ophthalmoscopes with adaptive optics correction of ocular aberrations provide retinal images of unprecedented resolution, allowing for real-time imaging of photoreceptors. Eye movements made by the subject/patient during recording produce distortions that must be corrected before multiple frames can be added together to achieve noise reduction or to build a mosaic image from different retinal areas. These distortions also provide a high spatial and temporal resolution record of the miniature eye movements made during fixation. Here we report simultaneous measurements of fixation eye movements with an Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) and a dual-Purkinje image (dPi) eye tracker in order to cross-validate these two methods of recording miniature eye movement. Method: Foveas of three subjects were imaged with a one degree square scan using the Houston AOSLO, at a resolution of 8 pixels per arc minute. A Generation V dPi tracker from SRI was placed in front of the AOSLO, and eye movements were recorded at the same time from the same eye being imaged by the AOSLO. AOSLO movies were analyzed off line to extract retinal image motion. The resulting traces were then overlaid on the dPi recordings for comparison. Results: The two methods produced records that agreed to within about one arc minute, with more significant disagreements occurring after eye blinks. Microsaccades in the dPi record were accompanied by overshoots that have previously been associated with lens wobble. AOSLO traces also showed saccade-related overshoots, but of much smaller amplitude. Conclusions: Eye movement recordings measured with dual Purkinje image trackers predict retinal image motion to a precision of about 1 arc minute, except for 10–20 milliseconds following each saccade and 500 – 1000 milliseconds following each eye blink. Retinal image motion measured directly from AOSLO recordings can be recovered to a precision of just a few arc seconds.

Validating and improving the correction of ocular artifacts in electro-encephalography

Reading is a complex cognitive process. Through eye tracking techniques the cognitive features can be observed in depth, and therefore a better grasp of the instant cognitive processing of language can be achieved. Compared to traditional methods, the greatest advantage of eye tracking is that is that the reader proceeds with reading coherently and fluently without interrupt and interference, which secures the results in higher ecological validity. This paper is mainly about studies on eye movement features in ESL reading, and particularly illustrates eye movement patterns, the relationship between eye movement and perceptual processing, and eye movement control, aiming at providing some basic evidences for explaining the relationship between eye movement behavior and cognitive processing thus helping to solve some theoretical problems in reading. DOI: http://dx.doi.org/10.11591/telkomnika.v13i2.6936

Eye and hand movement tracking has been proven to be a successful tool and is widely used to figure out characteristics of human cognition in language or visual processing (Just & Carpenter, 1976 Cognitive Psychology8441–480). Eye movement has proven to be a successful measure to figure out characteristics of human language and visual processing (Rayner, 1998 Psychological Bulletin124(3) 372–422). Recently, mouse tracking was used for social-cognition-like categorization of sex-atypical faces and studying spoken-language processes (Magnuson, 2005 PNAS102(28) 9995–9996; Spivey et al., 2005 PNAS102 10393–10398). Here, we present a framework that uses both eye gaze and hand movement simultaneously for analyzing the relation of them during memory retrieval. We tracked eye and mouse movements when the subject was watching a drama and playing a multimodal memory game (MMG), a cognitive task designed to investigate the recall memory mechanisms in watching video dramas (Zhang, 2009 AAAI 2009 Spring Symposium: Agents that Learn from Human Teachers 144–149). Experimental results show that eye tracking and mouse tracking provide complementary information about underlying cognitive processes. Also, we found some interesting patterns in eye-hand movement during multimodal memory recall.

The role of compensatory eye and head movements for gaze stabilization in the unrestrained frog

The present study utilized a new experimental set-up synchronizing eye movements and head motion for investigating referential change occurring in a reading task. We examined the effects of a change in narrative perspective during reading on eye movements and head motion. Forty-four participants read texts on a digital tablet, and both participants' eye movements and head movements were recorded using eye tracker and motion capture. The results showed longer eye fixation duration, longer reading time and decreasing head motions when perspective changed. Recent studies have supported the dynamic engagement hypothesis suggesting that there is a fluctuation in cognitive engagement reflected by postural movements. Our findings on head movements seem to validate this hypothesis of a bodily engagement in reading. The results provided by our study showed that the novel methodology of eye and head movement recordings we used was proven to be informative in studying the reader's embodiment during reading.

BackgroundTo examine the speed and accuracy of saccadic eye movements during a novel eye tracking threshold visual field assessment and determine whether eye movement parameters may improve ability to detect glaucoma.MethodsA prospective study including both eyes of 31 patients with glaucoma and 23 controls. Standard automated perimetry (SAP) and eye tracking perimetry (saccadic vector optokinetic perimetry, SVOP) was performed. SVOP provided data on threshold sensitivity, saccade latency, and two measures of accuracy of saccades (direction bias and amplitude bias). The relationship between eye movement parameters and severity of glaucoma was examined and Receiver Operating Characteristic curves were used to assess ability to detect glaucoma.ResultsPatients with glaucoma had significantly slower saccades (602.9 ± 50.0 ms versus 578.3 ± 44.6 ms for controls, P = 0.009) and reduced saccade accuracy (direction bias = 7.4 ± 1.8 versus 6.5 ± 1.5 degrees, P = 0.006). There was a significant slowing of saccades and saccades became less accurate with worsening SAP sensitivity. Slower saccades were associated with increased odds of glaucoma; however, the AUC for saccade latency was only 0.635 compared to 0.914 for SVOP sensitivity.ConclusionPatients with glaucoma had significant differences in eye movements compared to healthy subjects, with a relationship between slower and less accurate eye movements and worse glaucoma severity. However, in a multivariable model, eye movement parameters were not of additional benefit in differentiating eyes with glaucoma from healthy controls.

Optical blur and ageing are known to affect driving performance but their effects on drivers' eye movements are poorly understood. This study examined the effects of optical blur and age on eye movement patterns and performance on the DriveSafe slide recognition test which is purported to predict fitness to drive. Twenty young (27.1 ± 4.6 years) and 20 older (73.3 ± 5.7 years) visually normal drivers performed the DriveSafe under two visual conditions: best-corrected vision and with +2.00 DS blur. The DriveSafe is a Visual Recognition Slide Test that consists of brief presentations of static, real-world driving scenes containing different road users (pedestrians, bicycles and vehicles). Participants reported the types, relative positions and direction of travel of the road users in each image; the score was the number of correctly reported items (maximum score of 128). Eye movements were recorded while participants performed the DriveSafe test using a Tobii TX300 eye tracking system. There was a significant main effect of blur on DriveSafe scores (best-corrected: 114.9 vs blur: 93.2; p < 0.001). There was also a significant age and blur interaction on the DriveSafe scores (p < 0.001) such that the young drivers were more negatively affected by blur than the older drivers (reductions of 22% and 13% respectively; p < 0.001): with best-corrected vision, the young drivers performed better than the older drivers (DriveSafe scores: 118.4 vs 111.5; p = 0.001), while with blur, the young drivers performed worse than the older drivers (88.6 vs 95.9; p = 0.009). For the eye movement patterns, blur significantly reduced the number of fixations on road users (best-corrected: 5.1 vs blur: 4.5; p < 0.001), fixation duration on road users (2.0 s vs 1.8 s; p < 0.001) and saccade amplitudes (7.4° vs 6.7°; p < 0.001). A main effect of age on eye movements was also found where older drivers made smaller saccades than the young drivers (6.7° vs 7.4°; p < 0.001). Blur reduced DriveSafe scores for both age groups and this effect was greater for the young drivers. The decrease in number of fixations and fixation duration on road users, as well as the reduction in saccade amplitudes under the blurred condition, highlight the difficulty experienced in performing the task in the presence of optical blur, which suggests that uncorrected refractive errors may have a detrimental impact on aspects of driving performance.

IntroductionThe use of eye tracking (ET) in mathematics education research has increased in recent years. Eye tracking is a promising research tool in the domain of functions, especially in graph interpretation. It promises to gain insights into learners’ approaches and ways of thinking. However, for the domain of functions and graph interpretation, it has not yet been investigated how eye-tracking data can be interpreted. In particular, it is not clear how eye movements may reflect students’ cognitive processes. Thus, in this study, we investigate in how far the eye-mind hypothesis (EMH), which states broadly that what the eye fixates is currently being processed, can be applied to this subdomain. This is particularly true for contextual graphs, whose data originate from real-world situations, and which are of central importance for the development of mathematical literacy. The aim of our research is to investigate how eye movements can be interpreted in the domain of functions, particularly in students’ interpretations of contextual graphs.MethodsWe conducted an exploratory case study with two university students: The students’ eye movements were recorded while they worked on graph interpretation tasks in three situational contexts at different question levels. Additionally, we conducted subsequent stimulated recall interviews (SRIs), in which the students recalled and reported their original thoughts while interpreting the graphs.ResultsWe found that the students’ eye movements were often related to students’ cognitive processes, even if indirectly at times, and there was only limited ambiguity in the interpretation of eye movements. However, we also found domain-specific as well as domain-general challenges in interpreting eye movements.DiscussionOur results suggest that ET has a high potential to gain insights into students’ graph interpretation processes. Furthermore, they point out what aspects, such as ambiguity and peripheral vision, need to be taken into consideration when investigating eye movements in the domain of functions.

The ocular motor system consists of several subsystems, including the vestibular ocular nystagmus saccade system, the pursuit system, the fixation and gaze-holding system and the vergence system. All these subsystems aid the stabilization of the images on the retina during eye and head movements and any kind of disturbance of one of the systems can cause instability of the eyes (e.g. nystagmus) or an inadequate eye movement causing a mismatch between head and eye movement (e.g. bilateral vestibular failure). In both situations, the subjects experience a movement of the world (oscillopsia) which is quite disturbing. New insights into the patho-physiology of some of the ocular motor disorders have helped to establish new treatment options, in particular in downbeat nystagmus, upbeat nystagmus, periodic alternating nystagmus, acquired pendular nystagmus and paroxysmal vestibular episodes/attacks. The discussed patho-physiology of these disorders and the current literature on treatment options are discussed and practical treatment recommendations are given in the paper.

BackgroundThough cognitive remediation has shown modest benefits for schizophrenia, relatively few training programs for have targeted the visual processing deficits common in the illness. Residual visual processing deficits following cognitive remediation may explain why cognitive remediation has had limited effects on visual learning and memory compared to auditory learning and memory. We sought to test whether training early visual processing would improve visual memory and facial affect recognition by targeting a well-characterized visual deficit in schizophrenia: visual backward masking (VBM). The deficit is so common in schizophrenia, and in non-affected family members to a lesser degree, that it is viewed as an endophenotype. The VBM deficit, however, can normalize as we have previously shown. In our prior open-label pilot study, individuals with schizophrenia (Surti and Wexler, 2012) made substantial gains in VBM performance with rudimentary computerized VBM training. The VBM improvements were also accompanied by improvements in visual memory.To test the hypothesis that improved early sensory training could lead to other cognitive gains in the same domain, we conducted a randomized control study with a new, more sophisticated computerized VBM training program, and compared it to an active control condition. We expected that visual memory and facial affect recognition would improve with the novel visual training (VT), and that VBM would improve with the VT as well.Methods23 individuals with stable schizophrenia or schizoaffective disorder were randomized to receive 20 sessions of VT or an active control. The VT consisted of VBM training with multiple levels of difficulty, adaptive tracking, virtual rewards, and a variety of letters, numbers, and shapes to train different areas of the visual field. The active control condition was a commercially available computerized typing tutorial (TT) with animation, game narrative, and multiple typing activities. Participants were tested before and after training with: the Matrics Cognitive Consensus Battery (MCCB), including the Brief Visuospatial Memory Test-Revised (BVMT) as the study’s primary outcome; the Profile of Nonverbal Sensitivity (mini-PONS) to assess non-verbal social cues; standardized VBM tests; and typing assessments. Repeated measure ANOVAs were conducted in SPSS24 after checking for normality.Results22 of 23 individuals completed the study, and by participants’ reports, both interventions were well tolerated, equally enjoyable and equally motivating, though the VT was slightly more frustrating for participants. Even when co-varying for education, which was higher in the VT group, there were no condition by time interactions for the BVMT, the mini-PONS, overall MCCB, or typing ability. There was a significant condition by time interactions for VBM performance (F = 5.8, p =0.028), with a substantial improvement in the VT group (Cohen’s d = 0.54; p=0.004).DiscussionPatients with schizophrenia equally tolerated a computerized visual training designed in-house and an off-the shelf highly gamified control training, but only the visual training, specifically designed for individuals with schizophrenia, had effects on the trained task. The effects of the visual training did not generalize to visual memory, facial affect recognition, or global cognition, so further work is needed to facilitate generalization.

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Saccadic eye movements are extremely rapid and jerk-like shifts of the eyes (up to 900 deg s−1) with which we explore our environment between periods of fixation, and other oculomotor tasks. We perform about 20 000–25 000 of such highly accurate eye movements per day to bring visual targets of interest onto our foveae. To achieve such precision, eye movements in general, and saccades in particular, need to be space–time coordinated. An article by Cromer & Waitzman (2006) in this issue of The Journal of Physiology suggests one mechanism of how space–time coordination of saccadic eye movements in the horizontal plane could be achieved by a little known and little studied area in the brainstem, the central mesencephalic reticular formation (cMRF). Although discovered years ago by the Cohen group (Cohen & Büttner-Ennever, 1984; Cohen et al. 1985, 1986), its existence had been largely neglected until the Waitzman group recently unearthed it. The classically defined cMRF is located lateral to the oculomotor nucleus (Fig. 1), dorsal to the caudal pole of the red nucleus and ventral to the posterior commissure. Different cMRF regions receive projections from small and large saccade areas of the superior colliculus (Cohen & Büttner-Ennever, 1984; Cohen et al. 1986). Stimulation of the dorsal cMRF induces fixed vector saccades (‘retinocentric’), i.e. of constant amplitude and direction regardless of the initial eye position, whereas in the ventral cMRF saccade amplitude varies depending on eye position (Cohen et al. 1985). Summary of connections of the central mesencephalic reticular formation (cMRF) The cMRF receives input from the frontal eye fields (FEFs), supplementary eye fields (SEFs) and superior colliculus (SC). Reciprocal ‘feed-back’ projections reach the SC from the cMRF. ‘Feed-forward’ projections from the cMRF target populations involved in head movements (brainstem head movement centres and cervical spinal cord) and eye movements (e.g. horizontal saccade generator network containing excitatory burst neurones (EBNs) in the paramedian pontine reticular formation (PPRF), inhibitory burst neurones (IBNs) and omnipause neurones (OPNs). Bilateral monosynaptic projections exist both to medial rectus (MR) motoneurones in the oculomotor nucleus (III) and to ‘slow’ and ‘fast’ abducens (VI) motoneurones (MNs), which innervate the lateral rectus muscle (LR). While feed-back projections from the cMRF to the SC and feed-forward projections (e.g. to PPRF) are mediated by separate neurone populations, it is unknown whether the same applies to the various other efferent projections from the cMRF. Direct projections from the cMRF to fast LR and MR MNs represent another pathway for horizontal saccade generation, in addition to traditional saccade generation pathways (involving projections from the FEFs via the SC to the PPRF, and from the PPRF to ipsilateral LR MNs and abducens internuclear neurones, AIN, and subsequently contralateral MR MNs for the production of horizontal conjugate eye movements). In addition, the cMRF plays a role in the coordination of eye and head movements, i.e. in gaze control. INC, interstitial nucleus of Cajal. The important role the cMRF is playing for space–time coordinated rapid eye movements, as shown in the article by Cromer & Waitzman (2006), has to be seen in the following context. While we may be looking anywhere at a given moment in time when an object of interest appears in our visual field, we are able to capture such a target immediately with a saccadic eye movement. The superior colliculus provides a spatial map of the visual environment of interest. The spatial code for target-selecting saccadic eye movements exists in the form of a vector representation of a given target location that allows us to shift gaze from one place to any other place in the visual field. However, up to now, it has been unclear which neuronal circuits are actually involved in performing such a movement vector calculation, since the superior colliculus only offers a spatial map but not the temporal aspect of the required eye movement. Cromer & Waitzman (2006) now offer the suggestion that various feed-back and feed-forward loops between the cMRF, the superior colliculus and the premotor saccade generator network (Fig. 1), including neurones within the cMRF, constitute a network that allows the space–time coordination of target-selecting rapid eye movements. They have identified eight different neurone types within the cMRF related to one or more saccade metric parameters and combinations thereof, e.g. velocity, duration, amplitude, etc. They argue that these different neurone types indicate different processing stages of spatial–temporal transformations via multiple anatomical pathways and physiological mechanisms. Projections from the cMRF to the premotor saccade generator network (EBNs, IBNs, OPNs) would serve as the feed-forward signals of the now time-coordinated and space-coded collicular outflow, whereas the projections from the cMRF to the superior colliculus would provide the necessary feed-back flow. Neuroanatomical tract tracing results with a retrograde transneuronal marker have shown that the cMRF also innervates directly, i.e. monosynaptically, lateral rectus (Graf et al. 2000; Ugolini et al. 2001, and submitted) and medial rectus motoneurones (Graf et al. 2002). These direct projections may be part of the network involved in generation of combined eye and head movements, i.e. gaze control, since the cMRF also innervates the cervical spinal cord (Robinson et al. 1994; Scudder et al. 1996) and brainstem head movement centres (May et al. 2005; Perkins et al. 2005). Furthermore, the cMRF, like the superior colliculus, receives direct projections from the cortical frontal eye fields (FEFs) (Huerta et al. 1986; Stanton et al. 1988) and the supplementary eye fields (SEFs) (Huerta & Kaas, 1990; Shook et al. 1990) (Fig. 1). This makes the cMRF also a potential relay to transmit information related to saccade metrics from the FEFs and SEFs to horizontal extraocular motoneurones. Finally, the cMRF may even play a role in maintaining eye position, gaze holding and fixation. Monosynaptic projections from the caudal (horizontal) cMRF to lateral rectus and medial rectus motoneurones support such an idea of participation in stabilizing eye position and fixation, particularly as such projections also target the so-called ‘slow’ lateral rectus motoneurones (Ugolini et al. 2001, and submitted), and bilateral stimulation of the cMRF promotes fixation (Cohen et al. 1985). The bilateral monosynaptic projections from the cMRF to lateral rectus motoneurones are also a potential substrate for the transmission to these motoneurones of vergence signals (Mays & Gamlin, 1995). To summarize, the cMRF is embedded in an interconnected and complex network of eye movement circuits for the production of saccades, fixation, gaze holding and vergence (Fig. 1). It receives direct input from the cortical eye movement centres, the FEFs and SEFs, and it projects directly to horizontal, i.e. lateral and medial rectus, motoneurones. There it contacts both ‘fast’ and ‘slow’ motoneurones. Besides ocular motoneurones, the cMRF also contacts the horizontal saccade generator network (EBNs, IBNs, OPNs) and head movement related brainstem centres, and maintains reciprocal connections with the superior colliculus.

Reading Chinese, a kind of ideogram, relies more on visual cognition. The visuospatial cognitive deficit of Chinese dyslexia is an interesting topic that has received much attention. The purpose of current research was to explore the visuopatial cognitive characteristics of Chinese dyslexic children by studying their eye movements via a picture searching test. According to the diagnostic criteria defined by ICD-10, twenty-eight dyslexic children (mean age (10.12 +/- 1.42) years) were enrolled from the Clinic of Children Behavioral Disorder in the third affiliated hospital of Sun Yat-sen University. And 28 normally reading children (mean age (10.06 +/- 1.29) years), 1:1 matched by age, sex, grade and family condition were chosen from an elementary school in Guangzhou as a control group. Four groups of pictures (cock, accident, canyon, meditate) from Picture Vocabulary Test were chosen as eye movement experiment targets. All the subjects carried out the picture searching task and their eye movement data were recorded by an Eyelink II High-Speed Eye Tracker. The duration time, average fixation duration, average saccade amplitude, fixation counts and saccade counts were compared between the two groups of children. The dyslexic children had longer total fixation duration and average fixation duration (F = 7.711, P < 0.01; F = 4.520, P < 0.05), more fixation counts and saccade counts (F = 7.498, P < 0.01; F = 11.040, P < 0.01), and a smaller average saccade amplitude (F = 29.743, P < 0.01) compared with controls. But their performance in the picture vocabulary test was the same as those of the control group. The eye movement indexes were affected by the difficulty of the pictures and words, all eye movement indexes, except saccade amplitude, had a significant difference within groups (P < 0.05). Chinese dyslexic children have abnormal eye movements in picture searching, applying slow fixations, more fixations and small and frequent saccades. Their abnormal eye movement mode reflects the poor ability and strategy of visual information processing.

Color fusion and rivalry are two key information integration mechanisms in binocular vision, representing the visual system's processing patterns for consistent and conflicting inputs, respectively. This study hypothesizes that there are quantifiable differences in eye movement indicators under states of binocular color fusion and rivalry, which can be verified through multi-paradigm eye movement experiments. The experiment recruited eighteen subjects with normal vision (nine males and nine females), employing the Gaze Stability paradigm, Straight Curve Eye Hopping paradigm, and Smoothed Eye Movement Tracking paradigm for eye movement tracking. Each paradigm included a binocular color rivalry experimental group (R-G) and two binocular color fusion control groups (R-R, G-G). Data analysis indicates significant differences in indicators such as Average Saccade Amplitude, Median Saccade Amplitude, and SD of Saccade Amplitude between binocular color fusion and rivalry states. For instance, through Z-Score normalization and cross-paradigm merged analysis, specific ranges of these indicators were identified to distinguish between the two states. When the Average Saccade Amplitude falls within the range of -0.905--0.693, it indicates a state of binocular color rivalry; when the range is 0.608-1.294, it reflects a state of binocular color fusion. Subsequently, ROC curve analysis confirmed the effectiveness of the experimental paradigms in analyzing the mechanisms of binocular color fusion and rivalry, with AUC values of 0.990, 0.741, and 0.967, respectively. These results reveal the potential of eye movement behaviors as biomarkers for the dynamic processing of visual conflicts. This finding provides empirical support for understanding the neural computational models of binocular vision and lays a methodological foundation for developing visual impairment assessment tools based on eye movement features.