From Visual Attention to Literacy: Symbol Search Deficit Predicts Future Reading Difficulties From Age 3.

Poor reading has been associated with impaired simultaneous visual processing of multiple graphic symbols composed of separable features, a behavioral marker of reduced visual attention based on parietal dysfunction. We designed a visual search screening test, consisting of finding the (unique) black circle among circles combined with a bar of various length and location (black symbols) versus among circles of various colors. The temporal Gap between these symbol and color search conditions was previously validated as a significant visuo-attentional contributor of reading between ages 8 and 11, predicting its performance with moderate sensitivity, as reading difficulty is multifactorial, but high specificity. Here, we established its good positive predictive value in a longitudinal study with the same children being screened in kindergarten (at 3, 4, or 5 years old) and later assessed for reading performance at the second semester of third grade (at 8 years old). We also assessed 4 and/or 5 years old children with the knowledge of letter names, the early reading of classmates' first names and of small frequent words. The visual search screening test predicted future reading performance with lower correlation strength but as early as 3 years old, providing more lead time for specific preventive educational or clinical intervention during kindergarten in a subgroup whose pathological visual search performance at Age 3 was associated with a 5.7 times greater likelihood of later reading difficulties.