Using saccadic eye movements to assess cognitive decline with ageing

Abstract

Saccadic eye movements take place when the eyes are moved rapidly from one location in space to another. They are generally reflexive, taking place subconsciously when a scene is scanned, or when someone looks at an object which captures attention. Saccades can be inhibited when an alternative response is required, or when it is necessary to focus attention at a specific location. The degree to which individuals are able to inhibit saccades may be an index of cognitive processes, including working memory and inhibitory control, which may decline with age, especially in adults with dementia. This chapter describes two methods of assessing inhibitory control using saccades. Antisaccades involve making a voluntary saccade in the opposite direction to a cue stimulus, and the oculomotor capture task involves making a saccade to a target in the presence of a concurrent onset distractor. Both tasks involve the inhibition of a saccade to a stimulus which captures attention, and to make an alternative saccade. Older adults are less able to inhibit saccades in these tasks than younger adults, and some individuals in particular show substantial deficits in performance on both tasks. These results suggest that tests of inhibition of saccadic eye movements may be a valuable means of identifying older adults showing early signs of cognitive decline.