Sensory Loss and Dementia

Sensory loss in olfaction, vision and hearing are risk factors for dementia but the reasons for this are unclear. This review presents the neurobiological evidence linking each sensory modality to specific dementias and explores the potential mechanisms underlying this. Olfactory deficits can be linked to direct neuropathological changes in the olfactory system due to Alzheimer’s disease and Parkinson’s disease, and may be a marker of disease severity. Visual deficits potentially increase dementia risk in a vulnerable individual by reducing cognitive reserve. Hearing deficits may indicate a susceptibility to Alzheimer’s disease through a variety of mechanisms. More generally, sensory impairment could be related to factors related to resilience against dementia. Further research is needed to tease out the specific and synergistic effects of sensory impairment. Studying sensory loss in relation to neuropathological biomarkers is necessary to clarify the mechanisms involved. This could produce new monitoring and management strategies for people at risk of dementia.