Abstract
Early language experience has been proposed to play a central role in the development of higher cognition, but evidence from deaf and hard-of-hearing (DHH) individuals remains difficult to interpret because language ability, auditory access, and family language environment are often confounded. The present study examined fluid cognition in 208 DHH young adults with diverse histories of deafness onset, cochlear implantation, family background, and American Sign Language (ASL) acquisition. Participants completed objective measures of ASL proficiency and the NIH Toolbox Fluid Cognition Battery. Confirmatory factor analysis indicated that NIH Toolbox performance was better characterized by two latent factors, Executive Control and Memory, than by a single factor. Latent profile analysis identified four cognitive profiles reflecting dissociable patterns of performance across these domains. Traditional hearing-history and language ability variables, including age of cochlear implantation, age of deafness onset, age of ASL acquisition, and ASL comprehension and production measures did not individually predict latent cognitive factor scores. In contrast, a derived measure of early shared linguistic modality – indicating likely access to a common language modality between child and caregiver by age 3 years – significantly predicted both Executive Control and Memory scores. Early shared linguistic modality also predicted latent profile membership: participants with early shared language access had substantially lower odds of belonging to the lowest-performing cognitive profile. These findings suggest that adult cognitive outcomes among DHH individuals are associated less with auditory access per se than with early access to a shared, accessible language environment.