Mild-to-moderate hearing loss and language impairment: How are they linked?

• Mild-to-moderate hearing loss (MMHL) very often leads to impaired language, including impaired morphosyntax.
• Some children with MMHL have language impairment as severe as that observed in children with SLI; others have unimpaired language.
• Specific areas of morphosyntactic difficulty are shared with other acquisition contexts and can be characterized in terms of linguistic computational complexity.
• Degree of hearing loss does not predict language impairment; the link between hearing loss and language impairment is indirect.

What is the nature of the link between prelingual mild-to-moderate hearing loss (MMHL) and impaired language in children and adolescents? Although the scientific literature is sparse, it is clear that many experience considerable difficulty acquiring language, and that this difficulty is not limited to phonetic form. We report on a series of studies we have conducted involving a number of French-speaking children and adolescents (N > 80) aged 6–16, all of whom have bilateral sensorineural, prelingual hearing loss. Using a variety of methodologies to test a wide range of language skills, we have found that morphosyntactic development in children with MMHL is highly likely to be impaired, that it is often very severely impaired, and that difficulties continue into adolescence. Comparisons with other contexts of atypical acquisition of French, both with pathology (SLI, epilepsy) and without pathology (second language acquisition) show that aspects of morphosyntax which are subject to difficulty are not specific to the context of hearing loss. Although there is some evidence for correlations with degree of hearing loss, these are not regular and do not predict morphosyntactic performance: the link between hearing loss and language impairment is indirect. It is suggested that this link might be mediated by working memory and auditory attention, which could thus be explored as a plausible avenue for finding an explanation for the heterogeneity in language performance observed in individuals with MMHL.