Is there a relationship between hearing loss and language impairment in patients with dementia?: a systematic review

Abstract

[Abstract]

Background: Hearing loss (HL) and language impairment occur in the context of various types of cognitive impairment. There is extensive scientific literature on the relationship between HL and cognitive impairment or the risk of dementia, but its impact on language impairment is not well understood. This systematic review investigates the potential relationship between HL and language impairment in dementia patients.

Method: We conducted literature searches in the Scopus, Web of Science, and Medline databases from inception to May 2024 in accordance with PRISMA guidelines. Data extraction and methodological quality assessment, including risk of bias, were carried out.

Results: The search returned 767 articles for evaluation, which resulted in 14 that met the inclusion criteria. Overall, the results included 3676 older individuals, of whom 677 had dementia. Significant associations were observed between HL and language impairment, with a stronger association observed in comprehension than in production, although there was no evidence of causality.

Conclusion: Addressing hearing loss may play a role in managing language deficits in patients with dementia. Central auditory processing (CAP) and cognitive load are as critical as, if not more vital than, peripheral HL in language impairment in dementia patients. The quantification and directionality of the possible effects of language and hearing impairment on the genesis of dementia require longitudinal studies.