The good news is that a new long-term study of 6,520 people between the ages of 58 and 101 which is just out in the online issue of Neurology found that those people with just one sensory deficit of either hearing or vision had no increased risk of eventual dementia.
The bad news is that there seemed to be a synergistic effect between sensory losses so that those people in this study who had impairment of both those sensory functions had twice the risk of eventual dementia compared to the non-dementia group.
Why this synergistic effect?
It may be a direct negative effect on the brain.
More likely, though, is that people with both impaired hearing and impaired vision are much more likely to withdraw socially compared to more normal people, and this kind of isolation – physical, emotional, mental – likely leads to a significantly increased risk of cognitive decline.
The lesson here is simple: if you have any impaired sensory function, don’t ignore it – treat it with whatever treatment modality makes sense for you.