Sensory impairments in older persons is common but this is the first study to look at the number of sensory impairments (visual, hearing, smell, touch) as risk factors for dementia.
One sensory impairment was associated with a 50% greater risk of dementia, two impairments with a twofold greater risk, and three or four impairments was associated with a 2.8-fold greater risk of dementia.
The lead researcher stated that it is possible that sensory impairment, particularly multiple impairments could limit an older person's engagement in protective lifestyle factors such as physical, cognitive, and social activity, thereby increasing dementia risk.
Further studies are needed to determine whether multisensory impairment is a risk factor for dementia or an indicator of neurodegeneration.
Brenowitz, W et al UCSF 2018 April 26
But also reported in a recent syudy in China : J Am Geriatr Soc. 2018 Mar;66(3):480-486