# Extent of magnitude representation deficit and relationship with arithmetic skills in children with 22q11.2DS

## TL;DR

This study investigates how children with 22q11.2 deletion syndrome process numerical magnitudes and how this relates to their arithmetic skills.

## Contribution

The study clarifies that children with 22q11.2DS have a general magnitude representation deficit, not just a visuospatial one, and finds working memory is more linked to arithmetic skills.

## Key findings

- Children with 22q11.2DS showed a global magnitude representation deficit, regardless of visuospatial load.
- Performance in the magnitude comparison task did not correlate with arithmetic achievement in these children.
- Working memory, rather than magnitude representation, was more closely related to arithmetic skills in children with 22q11.2DS.

## Abstract

Previous studies have produced conflicting results concerning the extent of magnitude representation deficit and its relationship with arithmetic achievement in children with 22q11.2 deletion syndrome. More specifically, it remains unclear whether deficits are restricted to visuospatial content or are more general and whether they could explain arithmetical impairment.

Fifteen 5- to 12-year-old children with 22q11.2 deletion syndrome and 23 age-matched healthy controls performed a non-symbolic magnitude comparison task. Depending on the trial, participants had to compare stimuli with high or low visuospatial load (visuospatial stimuli or temporal sequence of visual stimuli). The participants also completed a battery of arithmetic skills (ZAREKI-R) and a battery of global cognitive functioning (WISC-V or WPPSI-IV), from which working memory and visuospatial indices were derived.

Children with 22q11.2DS responded as fast as healthy controls did but received fewer correct responses, irrespective of visuospatial load. In addition, their performance in the non-symbolic magnitude comparison task did not correlate with the ZAREKI total score, while the working memory index did.

Children with 22q11.2DS might suffer from a global magnitude representation deficit rather than a specific deficit due to visuospatial load. However, this deficit alone does not seem to be related to arithmetic achievement. Working memory might be a better concern of interest in favoring arithmetic skills in patients with 22q11.2 deletion syndrome.

Clinicaltrials, NCT04373226. Registered 16 September 2020.