Spatial and numerical processing in children with non-verbal learning disabilities.

Crollen et al. (2015) watched kids with Non-Verbal Learning Disability do number tasks on a computer. They compared them to same-age kids without NVLD.

The tasks asked children to pick the bigger number or press left/right for number size. The set-up let the team see if kids had a mental left-to-right number line.

Kids with NVLD got more answers wrong and showed no left-hand advantage for small numbers. This means they do not use the usual space-number link.

The missing SNARC effect is a red flag: without the mental number line, math facts may feel floating and un-anchored.

Diemer et al. (2023) followed NVLD students for three years and saw math fact retrieval slip further each grade. The snapshot from Virginie et al. now looks like the start of that downhill track.

Wachob et al. (2015) and Fernández-Cobos et al. (2025) found similar space-number gaps in autistic children. Together the papers say: weak visuospatial skills hurt number-line sense in both NVLD and autism.

Van Hoof et al. (2017) showed kids with dyscalculia struggle with fractions because they cling to small whole-number rules. NVLD kids instead lack the spatial map; both groups end up behind but for different reasons.

If you teach a child with NVLD, do not assume the left-to-right number line is in place. Add concrete spatial cues such as a ruler path on the desk, colored ten-frames, or hopping games that pair numbers with left-right moves. These scaffolds can anchor math facts and may slow the retrieval drop seen in later grades.