Reacción a "Reactions: Hearing aid use reduces risk of dementia in hearing-impaired people"

This study provides high quality evidence that those with hearing loss who use hearing aids are at lower risk of dementia than those with hearing loss who do not use hearing aids. This raises the possibility that a proportion of dementia cases could be prevented by using hearing aids to correct hearing loss. However, the observational nature of this study makes it difficult to be sure that hearing aids are actually causing the reduced risk of dementia.

Hearing aids produce slightly distorted sound, and the brain has to adapt to this in order for hearing aids to be helpful. People who are at risk of developing dementia in the future may have early changes in their brain that impair this adaptation, and this may lead to them choosing to not use hearing aids. This would confound the association, creating the appearance that hearing aids were reducing dementia risk, when actually their use was just identifying people with relatively healthy brains.

Hopefully the evidence from this paper will lead to randomised trials of hearing aid use that will provide a stronger foundation for public health advice about whether correcting hearing loss might help to prevent dementia.