Eyes on CVI: Eye movements unveil distinct visual search patterns in Cerebral Visual Impairment compared to ADHD, dyslexia, and neurotypical children
Marinke J. Hokken, Niklas Stein, Rob Rodrigues Pereira, Ingrid G. I. J. G. Rours, Maarten A. Frens, J. van der Steen, Johan J. M. Pel, Marlou J. G. Kooiker
Abstract
Visual search problems are often reported in children with Cerebral Visual Impairment (CVI). To tackle the clinical challenge of objectively differentiating CVI from other neurodevelopmental disorders, we developed a novel test battery. Visual search tasks were coupled with verbal and gaze-based measurements. Two search tasks were performed by children with CVI (n: 22; mean age (SD): 9.63 (.46) years) ADHD (n: 32; mean age (SD): 10.51 (.25) years), dyslexia (n: 28; mean age (SD): 10.29 (.20) years) and neurotypical development (n: 44; mean age (SD): 9.30 (.30) years). Children with CVI had more impaired search performance compared to all other groups, especially in crowded and unstructured displays and even when they had normal visual acuity. In-depth gaze-based analyses revealed that this group searched in overall larger areas and needed more time to recognize a target, particularly after their initial fixation on the target. Our gaze-based approach to visual search offers new insights into the distinct search patterns and behaviours of children with CVI. Their tendency to overlook targets whilst fixating on it, point towards higher-order visual function (HOVF) deficits. The novel method is feasible, valid, and promising for clinical differential-diagnostic evaluation between CVI, ADHD and dyslexia, and for informing individualized training. • Impaired visual search performance was found in CVI, but not in ADHD or dyslexia. • Unstructured and crowded displays are detrimental for children with CVI. • Visual selective attention deficits seem to underlie impaired visual search in CVI. • Gaze-based parameters offer new insights in visual search strategies and patterns. • This valid approach is promising for non-verbal and non-motor assessments.