Hearing aids and cochlear implants reduce cognitive decline, according to two new meta-analyses.

The first meta-analysis of eight studies followed 126,903 people for between two and 25 years. Compared with controls with uncorrected hearing loss, those using hearing aids were 19 per cent less likely to show any cognitive decline, allowing for confounders. 

Hearing aid users were 27 per cent less likely to move from mild cognitive impairment to dementia, 21 per cent less likely to show cognitive impairment and 17 per cent less likely to develop dementia than controls. 

The second meta-analysis of 11 studies followed 568 people for between three months and a year. Hearing aids and cochlear implants improved scores on tests assessing cognition by
3 per cent. 

Further studies need to determine the mechanisms underlying the cognitive benefits following hearing restoration and whether the improvement emerges in different types and severity of hearing loss. (JAMA Neurol doi:10.1001/jamaneurol.2022.4427)