Overlapping numerical cognition impairments in children with chromosome 22q11.2 deletion or Turner syndromes

Abstract

Children with one of two genetic disorders (chromosome 22q11.2 deletion syndrome and Turner syndrome) as well typically developing controls, participated in three cognitive processing experiments. Two experiments were designed to test cognitive processes involved in basic aspects numerical cognition. The third was a test of simple manual motor reaction time. Despite significant differences in global intellectual abilities, as measured by IQ tests, performance on the two numerical cognition tasks differed little between the two groups of children with genetic disorders. However, both performed significantly more poorly than did controls. The pattern of results are consistent with the hypothesis that impairments were not due to global intellectual ability but arose in specific cognitive functions required by different conditions within the tasks. The fact that no group differences were found in the reaction time task, despite significant differences in the standardized processing speed measure, further supports the interpretation that specific cognitive processing impairments and not global intellectual or processing speed impairments explain the pattern of results. The similarity in performance on these tasks of children with unrelated genetic disorders counters the view that numerical cognition is under any direct genetic control. Instead, our findings are consistent with the view that disturbances in foundational spatiotemporal cognitive functions contribute to the development of atypical representations and processes in the domains of basic magnitude comparison and simple numerical enumeration.

Evidence of the impact of visuo-spatial processing on magnitude representation in 22q11.2 microdeletion syndrome

“…With regard to non-numerical magnitude, some studies also found that people with 22q11DS had poorer performance when processing spatial and temporal continuous dimensions. Compared to age-matched controls, they were slower at comparing length (Simon et al, 2005;Simon et al, 2008), demonstrated less ability to reproduce rhythmic patterns as well as less sensitivity to temporal interval differences (Debbané, Glaser, Gex-Fabry, & Eliez, 2005;Gabriel Mounir, Debbane, Schaer, Glaser, & Eliez, 2011). These results 1 are consistent with the Theory of Magnitude proposed by Walsh (2003) who assumed the existence of a common metric system for representing number, space and time.…”

“…First, an impairment in all magnitude comparison tasks would suggest a generalized magnitude deficit for the processing of number, time and space, in keeping with the Theory of Magnitude proposed by Walsh (2003). A second pattern of result would show an impairment restricted to all numerical tasks (numerical magnitude judgment tasks) and would suggest a number sense deficit in accordance with the ANS view and with previous studies that already showed a less precise magnitude representation for symbolic and non-symbolic numerical stimuli in 22q11DS participants (Oliveira et al, 2014;Simon et al, 2008Simon et al, , 2005.…”

“…the fast and precise apprehension of small numerosities up to three or four) yielded inconsistent results depending on the reference group. The subitizing range has been shown to be reduced in 22q11DS children compared to a control group matched on chronological age (but with more than 30 points' difference in IQ, Simon et al, 2008) while other studies observed a similar subitizing range in 22q11DS children compared to control children who were closer in terms of verbal IQ (De Smedt et al, 2006;.…”

“…More in-depth studies provide evidence for poorer calculation abilities compared to control participants matched on age and IQ, especially in calculation tasks requiring the deployment of calculation procedures such as addition and subtraction with a carry, and multi-digit calculations (De Smedt et al, 2009;De Smedt, Reynvoet, Swillen, Verschaffel, & Ghesquière, 2008;De Smedt et al, 2006;Simon, Bearden, Mc-Ginn, & Zackai, 2005). Furthermore, despite demonstrating preserved transcoding abilities (De Smedt et al, 2009;De Smedt et al, 2006; individuals with this disorder often displayed difficulties in the counting range in a dot numerical estimation task (3-8 dots, Simon et al, 2005;Simon et al, 2008).…”

The processing of number scales beyond whole numbers in development: Dissociations in arithmetic in Turner’s syndrome

“…Their weakness does not emerge early in their arithmetical development as girls with TS show intact counting skills Murphy, Mazzocco, Gerner & Henry, 2006;Temple & Sherwood, 2002). Slow response times [RTs] have been reported but did not always reach statistical significance (Bruandet, Molko, Cohen & Dehaene, 2004;Simon et al, 2008;Temple & Sherwood, 2002).…”