No Common Factor Underlying Decline of Visual Abilities in Mild Cognitive Impairment

Introduction
Recent work has shown an association between cognitive and visual impairments and two main theories were advanced, namely the sensory deprivation and the common cause theories. Most studies considered only basic visual functions such as visual acuity or visual field size and evaluated the association with dementia.

Objectives
To reconcile between these theories and to test the link between visual and cognitive decline in mildly cognitive impaired people.

Methods
We employed a battery of 19 visual tasks on 39 older adults with mild cognitive impairment and 91 without any evidence of cognitive decline, as measured by the Montreal Cognitive Assessment.

Results
Our results show a strong association between visual impairment and mild cognitive impairment. In agreement with previous results with younger and healthy older adults, we found also only weak correlations between most tests in older adults with mild cognitive impairment.

Conclusion
Our results suggest that visual and cognitive abilities decline simultaneously, but they do so independently across visual and cognitive functions and across participants.