Search

Visual selective attention refers to the selection of relevant visual elements in a scene whilst ignoring irrelevant visual elements. Visual Selective Attention Dysfunctions (VSAD) are prevalent in children with Cerebral Visual Impairment (CVI), Attention Deficit Hyperactivity Disorder (ADHD), and Dyslexia. An important issue in the pediatric neuropsychological practice is how to discriminate between the task performance of these populations. We conducted a scoping review of the literature on visual search performance (VSP) in children with CVI, ADHD, and Dyslexia, aged 6-12 years. After a systematic selection process, 35 studies were included. Results suggest that all patient groups have some degree of impaired VSP compared to typically developing children. Children with CVI tend to react slower and less accurately. VSP impairments in children with ADHD are characterized by poor accuracy rather than reaction time. Children with Dyslexia tend to be slower and less accurate, depending on stimulus type. Besides VSAD, it is argued that other neurocognitive mechanisms might influence VSP, such as speed-accuracy trade-off or an executive functioning deficit in ADHD and a phonological deficit in Dyslexia. This paper further discusses the differences and similarities in visual search performance between the groups. The sparse data in children with an official diagnosis of CVI and the technical inconclusive data on children with ADHD and Dyslexia demonstrate complexity of discriminating between these populations in clinical practice based on VSP. New and more quantitative VSP parameters, such as eye tracking-based measures, may contribute to a refined classification among CVI, ADHD, and Dyslexia.

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 less than 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 slower visuospatial reaction times. At two years, despite attention and motion reaction times becoming significantly faster, 20% had delayed attentional reaction times and 35% had delayed motion reaction times, but no correlations with MRI scores were found. The presence of structural brain damage was associated with abnormal functional performance over age. Conclusions The present study indicates an association between moderate to severe brain damage and visuospatial attention and motion processing dysfunction at one year corrected age. This provides a new perspective on comprehensive MRI scoring and quantitative functional visuospatial assessments and their applicability in children born very preterm in their first years of life.

Background Peripheral and central visual processing development highly depends on the integrity of the visual sensory system and the allocation of visuospatial attention. Method We quantitatively followed visual sensory functions (VSF) and visuospatial orienting functions (VOF) over two years in 77 children (1–13 years) with different types of visual pathology. Results Within the clinical groups, VSF were relatively constant over two years, except visual acuity, and VOF were characterized by longer reaction time, shorter fixation duration, and lower fixation accuracy than normal for their age. Children with peripheral pathology had high rates of abnormal VSF, of changes to abnormal visual acuity at 1–6 years, and larger and more abnormal VOF (fixation inaccuracy). Children with central pathology had relatively good VSF, whereas two-third had delayed orienting reaction times that differed from other groups mainly at 1–6 years. Conclusion The distinct patterns of quantitative VSF and VOF over time between the visual pathology groups, and the finding that both methods provided complementary information, argues for combining both types of assessments to provide comprehensive monitoring of visual functioning in children from a young age.

Background Children born preterm are at risk of visuospatial attention orienting and processing dysfunctions, which can be quantified early in life using visually-guided eye movement responses. Aims To identify the prevalence and perinatal risk factors for visuospatial attention orienting and processing dysfunctions in children born preterm of 1 year of corrected age (CA). Study design 123 children born between 26 and 33 weeks of gestation underwent a nonverbal visuospatial test at 1y CA, using an eye tracking-based paradigm. For the detected high-salient (cartoon and contrast), intermediate-salient (form and motion) and low-salient (color) stimuli, we quantified the reaction time to fixation (RTF). RTFs were compared to normative references from an age-matched control group (N = 38). The prevalence of perinatal risk factors (gestational age and weight, indices of neurological damage, overal sickness, respiratory failure, and retinopathy) was compared between the groups with normal and delayed RTFs. Results At 1y CA, the preterm group had 7–20% less detected stimuli than the control group, particularly for intermediate and low-salient stimuli. Compared to normative RTFs, modest delays were found for high-salient cartoon (in 19% of preterm children) and contrast (8%), intermediate-salient motion (23%) and form (21%), and low-salient color stimuli (8%). These children had a significantly higher prevalence of perinatal risk factors for respiratory failure and intraventricular hemorrhages. Conclusions Children born between 26 and 32 weeks have a modest risk (8–23%) of visuospatial attention and processing dysfunction. This warrants early monitoring and support of general visual development in preterm children at risk of respiratory distress and disrupted cerebral blood flow.

Visual closure is the ability to visualize a complete whole when an incomplete picture is presented. The aim of the present study was to investigate the Kaufman Gestalt closure task in children with cerebral and ocular visual impairments. Looking behavior was assessed by an eye tracker system to quantify the number and duration of fixations. We found that children with visual impairments due to cerebral damage show weaker Gestalt perception and had different looking patterns than children with ocular or without visual impairments. Children with brain damage performed significantly worse on the animate items than the group without brain damage.

textabstractPurpose: 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.

Children with visual impairments are very heterogeneous in terms of the extent of visual and developmental etiology. The aim of the present study was to investigate a possible correlation between prevalence of clinical risk factors of visual processing impairments and characteristics of viewing behavior. We tested 149 children with visual information processing impairments (90 boys, 59 girls; mean age (SD) = 7.3 (3.3)) and 127 children without visual impairments (63 boys and 64 girls, mean age (SD) = 7.9 (2.8)). Visual processing impairments were classified based on the time it took to complete orienting responses to various visual stimuli (form, contrast, motion detection, motion coherence, color and a cartoon). Within the risk group, children were divided into a fast, medium or slow group based on the response times to a highly salient stimulus. The relationship between group specific response times and clinical risk factors was assessed. The fast responding children in the risk group were significantly slower than children in the control group. Within the risk group, the prevalence of cerebral visual impairment, brain damage and intellectual disabilities was significantly higher in slow responding children compared to faster responding children. The presence of nystagmus, perceptual dysfunctions, mean visual acuity and mean age did not significantly differ between the subgroups. Orienting responses are related to risk factors for visual processing impairments known to be prevalent in visual rehabilitation practice. The proposed method may contribute to assessing the effectiveness of visual information processing in children. (C) 2014 Elsevier Ltd. All rights reserved.

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 developing children none of the outcome measures significantly differed between sessions. In the children with visual impairments similar results were obtained, except for motion. This stimulus elicited significantly faster reaction times in the second session. In at least 80% of the children reliable reaction times could be calculated if 4 responses to a cartoon stimulus and 1 or 2 responses to the other stimuli were measured. Comparison with existing method(s): The existing method to quantify visual information processing has been refined: the range of visual functions was extended and a criterion for reliable assessment of orienting response times was established. Conclusions: Objective measurement of orienting responses is a reliable method to test the initial stage of visual processing in children with and without visual impairments. A set minimum number of responses for each stimulus warrants the reliability of measurements obtained with this functional method in clinical practice. (C) 2014 Elsevier B.V. All rights reserved.

Visual problems that occur early in life can have major impact on a child's development. Without verbal communication and only based on observational methods, it is difficult to make a quantitative assessment of a child's visual problems. This limits accurate diagnostics in children under the age of 4 years and in children with intellectual disabilities. Here we describe a quantitative method that overcomes these problems. The method uses a remote eye tracker and a four choice preferential looking paradigm to measure eye movement responses to different visual stimuli. The child sits without head support in front of a monitor with integrated infrared cameras. In one of four monitor quadrants a visual stimulus is presented. Each stimulus has a specific visual modality with respect to the background, e.g., form, motion, contrast or color. From the reflexive eye movement responses to these specific visual modalities, output parameters such as reaction times, fixation accuracy and fixation duration are calculated to quantify a child's viewing behavior. With this approach, the quality of visual information processing can be assessed without the use of communication. By comparing results with reference values obtained in typically developing children from 0-12 years, the method provides a characterization of visual information processing in visually impaired children. The quantitative information provided by this method can be advantageous for the field of clinical visual assessment and rehabilitation in multiple ways. The parameter values provide a good basis to: (i) characterize early visual capacities and consequently to enable early interventions; (ii) compare risk groups and follow visual development over time; and (iii), construct an individual visual profile for each child.

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 of response times with age was influenced by effective salience: Response times to targets with high salience reached stable values earlier in development (around 4 years of age) than to targets with low salience (around 9 years of age). Intra-individual response time variability was highest for low-salient stimuli, and stabilized later (around 4 years) than for highly salient stimuli (2 years). The improvement of eye movement response times to visual modalities in PL stimuli occurred earlier in development for highly salient than for low-salient targets. The present age-dependent and salience-related results provide a quantitative and theoretical framework to assess the development of visuospatial attention, and of related visual processing capacities, in children from 1 year of age.

Quantification of orienting responses can be used to differentiate between children with cerebral visual impairment and infantile nystagmus syndrome. To further improve the sensitivity of this method, we compared orienting responses to a Cartoon stimulus, which contains all sorts of visual information, to stimuli that contain only Contrast, Form coherence, Motion coherence, Color and Motion detection. The stimuli were shown on an eye tracker monitor using a preferential looking paradigm. We found that both groups of children showed general slowing in orienting responses compared to controls. The children with cerebral visual impairment had significantly prolonged responses to Cartoon compared to the children with nystagmus, whereas the children with nystagmus had prolonged responses to Motion detection and larger fixation areas. Previously reported differences in orienting responses to Cartoon were replicated. Application of specific visual information did not alter the sensitivity of the method to distinguish between children with visual processing deficits.

We recently introduced a method based on quantification of orienting responses toward visual stimuli to assess the quality of visual information processing in children. In the present study, we examined the relationship between orienting responses and factors that are associated with visual processing impairments in current clinical practice. Response time and fixation quality to visual features such as form, contrast, motion, and color stimuli were assessed in 104 children from 1 to 12 years attending special education for the visually impaired. Using regression analysis, we investigated whether these parameters were affected by clinical characteristics of children. Response times significantly depended on stimulus type. Responses to high-contrast cartoons were significantly slower in children with a clinical diagnosis of cerebral visual impairment. Fixation quality was significantly affected by visual acuity and nystagmus. The results suggest that the quantitative measurement of orienting responses is strongly related to cerebral visual impairment in children.