Normal saccades but decreased fixation stability in a population of children with dyslexia

Developmental dyslexia affects around 5-15% of the population and has a heterogeneous aetiology. Optometric disorders are more prevalent in dyslexic populations but the relationship be- tween eye movement control and dyslexia is not well established. In this study, we investigated whether children with dyslexia show saccadic or fixation deficits and whether these deficits are related to deficits in visual acuity and/or accommodation. Thirty-four children with and without dyslexia were recruited for the project. All participants had an optometric examination and performed a saccade and fixation experiment. We used two eye movement paradigms: the step and the gap task. Eye movements were recorded by an infrared eye-tracker and saccade and fixation parameters were analysed separately. Saccadic latencies, premature saccades, and directional errors were similar between children with dyslexia and typically developing children. In contrast, fixations were significantly less stable in the dyslexic group. Neither saccades nor fixations were associated with deficits in accommodation or visual acuity. Children with dyslexia showed no difficulties in saccadic performance, but their fixation stability was reduced compared to the control group. The reduced fixation stability can be explained by general deficits in the cognitive processes that underpin eye movement control, that have also been found in other neuro-developmental disorders.

Oculomotor control in children with Special Educational Needs (SEN): the development and piloting of a novel app-based therapeutic intervention

Children with Special Educational Needs (SEN) often have impaired eye movement control which can impact on a wide range of everyday activities including in the classroom, socialising, participation in sport or crossing a road. Although some health practitioners offer eye movement therapies these tend not to have been systematically developed or evaluated. We have developed a new app to deliver eye movement training, based on detailed scientific understanding of eye movement control and extensive clinical experience with this patient group. We first investigated the acceptability of the app within several schools and made modifications based on detailed feedback from the children. Next, we conducted a pilot study to test the feasibility of using the app with 12 children (5–17 years old) who had SEN. The children successfully undertook app-based training for 10 min per day for 4–5 weeks. There was a high level of attendance and no attrition. We found some variation across participants in their ability to play on the app and the level of engagement. This indicates that pre-assessing children for ability and engagement may be important. This encouraging proof of concept study justifies the development of a full study. Given the time and money spent on existing commercially-offered or internet-based non-validated therapies, this would have substantial patient benefit regardless of the outcome: evidence of no effect could reassure parents that this kind of treatment was not needed, whilst evidence of effect suggests this as a useful treatment for children with poor oculomotor control.

The Thresholds of Greening Unit Serving Set as an Arousal Task Based on EEG and Eye Movement

Monotony is the most prominent characteristic feature of the prairie highway. Monotony can cause a decrease in the level of arousal, leading to lower vigilant. This study sets the greening unit as an arousal task to withstand the monotony and examines the different landscapes’ effects on EEG(electroencephalo-graph) and eye movement for drivers. 26 participants took part in a simulated driving experiment. Three scenes correspond to other greening units, respectively, one set as the control group without greening. The results show that the greening unit will improve driver vigilance and external eye movement control preponderance. The type of eye movement and [(alpha + theta) / beta] performance optimal arousal is immediate but discontinuous; The type of eye movement and alpha sample entropy show different spatial patterns of landscapes have different effective lengths. In conclusion,(1) Landscape（Fully open with triangular shape） provides superior arousal effect；(2)The greening unit length threshold corresponding to the optimal arousal level of drivers is 666 m; (3)The alpha sample entropy of less than 0.234 can be identified as the threshold of effect greening length

Synthesis

This chapter opens with a discussion of the limitations of current models of reading, and moves on to the reasons why more comprehensive models of reading are necessary to advance our understanding of the mental, perceptual, and motoric processes that support reading. The chapter then provides a comparative analysis of the various approaches that have been adopted to model reading, and how the theoretical assumptions of models of word identification, sentence processing, discourse representation, and eye-movement control might be combined to build a more comprehensive model of reading in its entirety. The remainder of the chapter then describes one such model, Über-Reader, and a series of simulations to illustrate how the model explains word identification, sentence processing, the encoding and recall of discourse meaning, and the patterns of eye movements that are observed during reading. The final sections of the chapter then address both the limitations and possible future applications of the model.