Math Abilities in Deaf and Hard of Hearing Children: The Role of Language in Developing Number Concepts

Deaf and hard of hearing (DHH) children who are not exposed to fluent sign language from birth generally fall behind their hearing peers in mathematics. These disparities are pervasive and emerge as young as 3 years old and continue throughout adulthood. While these limitations have been well-documented, there has been little attempt to empirically explain why one consequence of deafness seems to reflect difficulties with numbers and mathematics. The purpose of this review is to describe the math abilities of DHH children while providing an explanation as to why we see this disparity. In particular, we review evidence suggesting that limited/reduced language access, particularly in the first few months of life, may play a role in delaying the acquisition of early number concepts and its potential interference when solving math problems. We also consider the potential role executive functions, specifically working memory, play in mathematical learning and how lower working memory capacity seen in some DHH children may impact early numerical learning and task performance. Finally, we propose future research aimed to explain why deafness is often accompanied by difficulties in numerical cognition while informing our broader understanding of the relationship between language and numerical concepts.