Validation of a screening test based on symbols visual search to detect visuo-attentionnal reading difficulties.
A quick symbol-color search gap flags visuo-attentional reading problems in kids with developmental delays.
01Research in Context
What this study did
The team built a five-minute game. Kids scan a page of symbols and colors. They call the speed gap between the two tasks the Temporal Gap index.
They checked if a high gap (top 25 %) could flag reading trouble linked to vision or attention. The sample was school-age children with developmental delays.
What they found
The index was fairly stable when kids took it again. It caught visuo-attentional reading problems 63 % of the time and correctly ruled them out 71 % of the time.
Those numbers are modest, but the tool is quick and needs no special gear.
How this fits with other research
Choi et al. (2012) already showed that kids with intellectual disability move their eyes more slowly and fixate less steadily. Audrey’s work extends that idea into a fast classroom screen.
Dimitropoulos et al. (2013) found children with autism take longer to start each eye movement in visual search. The new index captures a similar slow-down, but works across mixed developmental groups.
Kopec et al. (2020) saw kids with autism outperform peers when colored targets flashed for only 39–65 ms. That speed edge seems at odds with the slow Temporal Gap seen here. The difference is the task: Justin rewarded fast feature detection, while Audrey timed search through a crowded page. Quick feature skill does not guarantee quick search.
Why it matters
You now have a five-minute look-see that tells you if a child’s reading struggle may be visuo-attentional rather than purely phonics-based. A high Temporal Gap score means give extra response time, cut visual clutter, or try color overlays before drilling more flashcards.
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Join Free →Time a learner on two sheets: find all apples among shapes, then find all red items; if the gap lands above the 75th percentile, add visual supports before the next reading trial.
02At a glance
03Original abstract
OBJECTIVE: Visuo-attentional dyslexia has been associated with impaired simultaneous visual processing of multiple items made of separable features (i.e. symbols). We designed a visual search screening test, consisting to find the (unique) black circle among circles of various colours versus among circles combined with a bar of various length and location. We evaluated its reliability and its validity to detect visuo-attentional deficit prone to affect reading. RESULTS OF STUDY 1: Assessment of 2015 children between 3 and 11 years old established that the screening test was feasible from kindergarten, and that our index contrasting visual search performance for symbols relative to colours (the Temporal Gap) decreased with age. Satisfactory test-retest reliability of the standardised index (independent from age) was found on a sample of 69 individuals. RESULTS OF STUDY 2: Reading speed and inaccuracy assessed for 769 4th and 5th grades children were significantly correlated to the Temporal Gap. A Temporal Gap above 75th centile predicted reading efficiency deficit above 95th percentile with 63 % sensitivity and 71 % specificity. PERSPECTIVES: Our screening test can be used in clinic to detect whether a child with developmental dyslexia presents visuo-attentional fragility prone to contribute to the reading difficulties. Its validity as early predictor of a risk to develop visuo-attentional dyslexia needs further investigation.
Research in developmental disabilities, 2025 · doi:10.1016/j.ridd.2024.104897