Language difficulties are a shared risk factor for both reading disorder and mathematics disorder

Area of Science:

• Developmental Psychology
• Neuroscience
• Educational Psychology

Background:

• Reading disorder (RD) and mathematics disorder (MD) often co-occur but are frequently studied independently.
• Children with preschool language difficulties or family history of dyslexia are at elevated risk for these disorders.

Purpose of the Study:

• To investigate the reading and arithmetic outcomes at age 9 in a longitudinal study of children at high risk for dyslexia.
• To identify the prevalence and characteristics of RD, MD, and comorbid RD&MD.
• To explore the relationship between language abilities, phoneme awareness, rapid automatized naming (RAN), inattention, and these disorders.

Main Methods:

• Longitudinal study of 224 children at high risk for dyslexia.
• Identification of RD, MD, and RD&MD groups using the 10th centile cutoff.
• Assessment of language, phoneme awareness, RAN digits, and inattention at age 9.

Main Results:

• High comorbidity between RD and MD was observed, with many cases also meeting criteria for developmental language disorder (DLD).
• A stepwise pattern was noted: RD > MD > RD&MD on measures of language, phoneme awareness, RAN digits, and inattention.
• Poor language skills were associated with all disorders and identified as a cognitive risk factor.

Conclusions:

• Shared genetic risk factors likely underlie both RD and MD.
• Developmental language disorder (DLD) is highly comorbid with RD and MD.
• Language proficiency is a critical cognitive factor influencing the development of both reading and math skills.