The co-occurrence of Attention-Deficit/Hyperactivity Disorder and mathematical difficulties: An investigation of the role of basic numerical skills.
ADHD alone does not damage basic number skills, so only provide math intervention when real math deficits show up.
01Research in Context
What this study did
von Wirth et al. (2021) compared kids with ADHD, kids with math difficulties, and kids with both. They gave each child tasks on basic number skills like writing numbers, comparing big and small sets, and recalling math facts.
The team used a quasi-experimental design. They matched groups by age and grade level.
What they found
Only the math-difficulty group showed clear gaps. They were slower at writing numbers, slower at comparing large sets, and slower at recalling math facts.
Kids who had ADHD alone scored the same as typical peers on every number task. ADHD by itself did not hurt basic numeracy.
How this fits with other research
Schwenk et al. (2017) meta-analysis agrees: symbolic comparison speed is the red flag for math problems, not the distance effect. Elena adds that this flag only waves when true math difficulties are present.
Pieters et al. (2012) and Gomez et al. (2020) found 1-2 year math delays and subitizing deficits in kids with DCD. Elena shows the opposite pattern for ADHD-only kids—no delays at all. The clash disappears when you see the diagnoses differ; motor disorder is not attention disorder.
Defever et al. (2013) showed mixed-notation matching taps access deficits in MLD. Elena’s MD group fits that profile, while their ADHD group does not, again tying the deficits to math status, not ADHD status.
Why it matters
If you screen a child with ADHD, do not assume weak math is part of the package. Run quick probes on number writing, symbolic comparison, and fact retrieval. If scores are low, treat the math difficulty, not the ADHD label. Save intervention time and avoid targeting the wrong skill set.
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02At a glance
03Original abstract
BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) and dyscalculia, also called mathematics disorder, frequently co-occur, yet the etiology of this comorbidity is poorly understood. AIMS: This study investigated whether impairments in the understanding of numbers and magnitudes (basic numerical skills) are a unique risk factor for mathematical difficulties (MD) or a shared risk factor that could help to explain the association between ADHD and MD. METHODS AND PROCEDURES: Basic numerical skills were assessed with eight subtests in children (age 6-10 years, N = 86) with clinically significant ADHD symptoms and/or MD and typically developing children (control group). This double dissociation design allowed to test for main and interaction effects of ADHD and MD using both classical and Bayesian analysis of variance (ANOVA). OUTCOMES AND RESULTS: Children with MD were impaired in transcoding, complex number and magnitude comparison, and arithmetic fact retrieval. They were not impaired in tasks assessing core markers of numeracy, which might be explained by the sample including children with mathematical difficulties instead of a diagnosed dyscalculia. ADHD was not associated with deficits in any of the tasks. The evidence for an additive combination of cognitive profiles was weak. CONCLUSIONS AND IMPLICATIONS: Impairments in basic numerical skills are uniquely associated with MD and do not represent a shared risk factor for ADHD symptoms and MD.
Research in developmental disabilities, 2021 · doi:10.1016/j.ridd.2021.103881