Development of salience-driven and visually-guided eye movement responses

Development of visuospatial attention can be quantified from infancy onward using visually-guided eye movement responses. We investigated the interaction between eye movement response times and salience in target areas of visual stimuli over age in a cohort of typically developing children. A preferential looking (PL) paradigm consisting of stimuli with six different visual modalities (cartoons, contrast, form, local motion, color, global motion) was combined with the automated measurement of reflexive eye movements. Effective salience was defined as visual salience of each target area relative to its background. Three classes of PL stimuli were used: with high- (cartoon, contrast), intermediate- (local motion, form), and low-effective salience (global motion, color). Eye movement response times to the target areas of the six PL stimuli were nonverbally assessed in 220 children aged 1-12 years. The development

Brain Damage and Visuospatial Impairments: Exploring Early Structure-Function Associations in Children Born Very Preterm

Background: To provide insight into early neurosensory development in children born very preterm, we assessed the association between early structural brain damage and functional visuospatial attention and motion processing from one to two years corrected age. Methods: In 112 children born at <32 weeks gestational age, we assessed brain damage and growth with a standardized scoring system on magnetic resonance imaging (MRI; 1.5 Tesla) scans performed at 29 to 35 weeks gestational age. Of the children with an MRI scan, 82 participated in an eye tracking-based assessment of visuospatial attention and motion processing (Tobii T60XL) at one year corrected age and 59 at two years corrected age. Results: MRI scoring showed good intra- and inter-rater reproducibility. At one year, 10% children had delayed attentional reaction times and 23% had delayed motion reaction times. Moderate to severe brain damage significantly correlated with s

Early intervention for children at risk of visual processing dysfunctions from 1 year of age: a randomized controlled trial protocol

BACKGROUND: An increasing number of children are suffering from brain damage-related visual processing dysfunctions (VPD). There is currently a lack of evidence-based intervention methods that can be used early in development. We developed a visual intervention protocol suitable from 1 year of age. The protocol is structured, comprehensive and individually adaptive, and is paired with quantitative outcome assessments. Our aim is to investigate the effectiveness of this first visual intervention program for young children with (a risk of) VPD. METHODS: This is a single-blind, placebo-controlled trial that is embedded within standard clinical care. The study population consists of 100 children born very or extremely preterm (< 30 weeks) at 1 year of corrected age (CA), of whom 50% are expected to have VPD. First, children undergo a visual screening at 1 year CA. If they are classified as being at risk of VPD, they are referred to standard care, which involves an ophthalmic and visual function assessment and a (newly developed) visual intervention program. This program consists of a general protocol (standardized and similar for all children) and a supplement protocol (adapted to the specific needs of the child). Children are randomly allocated to an intervention group (starting upon inclusion at 1 year CA) or a control group (postponed: starting at 2 years CA). The control group will receive a placebo treatment. The effectiveness of early visual intervention will be examined with follow-up visual and neurocognitive assessments after 1 year (upon completion of the direct intervention) and after 2 years (upon completion of the postponed intervention). DISCUSSION: Through this randomized controlled trial we will establish the effectiveness of a new and earl

Reliability of visual orienting response measures in children with and without visual impairments

Background: From the need for a quantitative method to examine visual processing in young children, we measured ocular orienting responses to visual stimuli (form, motion, expansion, color, contrast, cartoons). Reliability and applicability of this method were assessed. New method: 80 children (1-12 years) with visual impairments and a reference group of 118 typically developing children (1-6 years) completed two sessions. Test-retest reliability was measured by calculating differences in reaction time and fixation accuracy between the two sessions. For applicability, the cumulative percentage of children that fell within a pre-defined reliability interval was plotted against the mean number of responses. Results: In typically develo

Quantification of visual function assessment using remote eye tracking in children: Validity and applicability

Purpose: Measurements of visual and oculomotor functions are essential for providing tailored support to visually impaired children. In young or intellectually disabled children these measurements can be difficult or even impossible to perform. Recordings of orienting gaze in response to specific visual information, made with eye tracking, may offer a solution. The aim of this study was to observe and quantify eye tracking (ET)-based gaze responses to provide information about visual and oculomotor functioning, and to compare this information with standard visual function assessments (VFA). Methods: One hundred and twenty-six visually impaired children from 1-14 years underwent a VFA. Next they underwent a remote ET test. Four aspects of oculomotor control (nystagmus, fixation, saccades, pursuit) and three visual functions (visual field, contrast, colour) were selected to compare both methods. Performance was assessed (1) during VFA using standard behavioural observation and test scores and (2) after ET by observing and scoring the eye movement recordings. Validity, in terms of agreement between results, was measured by correlation analyses. From the orienting gaze responses, quantitative parameters (gain, fixation duration and directional saccades) were calculated to characterize visual performance. Results: Good agreement between the two test methods was found for observational assessment of oculomotor control and visual functions (correlations ranging from rs = 0.39 to rs = 0.69). The quantitative parameters of visual performance showed distinct results between children with and without specific functional impairments, both in children aged 1-6 and 7-14 years. Conclusion: Eye tracking-based gaze recordings are a promising tool to assess oculomotor and visual performance in a communication-free manner. Calculating quantitative parameters from specific gaze responses could assist in the characterization of functional visual performance in children, independent of age. Gaze responses are a useful addition to standard VFA in clinical practice