Reading and mathematics difficulties frequently co-occur, yet the cognitive and neural mechanisms underlying this overlap remain poorly understood. This thesis investigated the distinct and overlapping cognitive profiles underlying early mathematical achievement and reading risk, integrating behavioural and neuroscientific perspectives. A community sample of 138 children aged 5–7 years completed assessments of mathematics, reading, phonological processing, magnitude processing, executive functions, processing speed, and spatial reasoning. Structural equation modelling examined continuous variation in mathematical achievement; multinomial and binary logistic regression compared cognitive profiles across four risk groups (low risk, reading risk only, mathematics risk only, co-occurring risk). These studies were complemented by a systematic review of neuroimaging evidence on mathematical processing in dyslexia.

The structural equation model explained 81% of variance in mathematical achievement. Foundational numerical knowledge was the strongest unique predictor, followed by spatial reasoning, decoding, and working memory. Logistic regressions revealed profile specific patterns: phonological processing selectively predicted reading involved risk, while basic mathematical skills and spatial skills distinguished all at risk groups, and working memory was uniquely associated with the co-occurring profile. Reading risk was characterised by phonological deficits, mathematics risk by weaknesses in early numeracy, symbolic magnitude processing, working memory, and spatial reasoning, and the co-occurring group by broad weaknesses across domains. Although factorial ANOVAs showed independent main effects of reading and mathematics risk without interaction, direct pairwise comparisons were largely non-significant after correction, likely reflecting limited power in the smaller risk subgroups, precluding firm confirmation of an additive profile. The systematic review of eight neuroimaging studies indicated that children with dyslexia exhibit reduced, delayed, and less differentiated neural activation during symbolic mathematical tasks, with disrupted functional integration across phonological and numerical networks.

These findings demonstrate that early mathematical achievement is shaped by domain specific numerical foundations, spatial reasoning, verbal symbolic decoding, and working memory, with distinct cognitive predictors differentiating risk profiles. This thesis provides the first integrated behavioural and neural framework for understanding co‑occurring reading and mathematics difficulties, revealing a convergent pattern of profile‑specific vulnerabilities and independent risk contributions strongly suggestive of cumulative risk accumulation. However, replication in larger samples is essential to confirm the precise nature of this risk interaction.