Immersive virtual reality with eye tracking for diagnostic spatial memory testing

Aging produces subtle cognitive decline in various functions, including working memory, spatial memory and spatial navigation. With respect to spatial memory, older adults tend to adopt egocentric strategies - i.e. locating objects relative to oneself rather than allocentric strategies (locating oneself relative to the environment), potentially reflecting the structural changes occurring in medial temporal lobe (MTL) areas responsible for allocentric representation and in particular the hippocampus.
Neurodegeneration due to Alzheimer's disease (AD) is characterized by early neural damage to the entorhinal cortex, hippocampus, and other areas of the MTL-critical structures supporting allocentric processing of information. Critically, the same neuropathological changes occurring in Alzheimer's disease have been found also in the healthy ageing brain, putting AD at one end of a 'continuum' from healthy ageing.
Memory processing in the MTL has also been shown to guide eye movements during visual exploration. The connection between MTL memory processes and eye movements suggests the latter may be a good candidate for detecting damage to the former. This may help diagnose Alzheimer's disease (AD). Indeed, evidence suggests the tendency to view novel stimuli over previously viewed stimuli is reduced in people with mild cognitive impairment (MCI), a precursor condition to AD. However, the effect of allocentrically-demanding tasks on eye-movements has not been investigated. We reasoned that testing allocentric spatial memory through eye movements may be a promising avenue for diagnostic testing of Alzheimer's disease.
This PhD project will look at subtle differences in eye movements occurring during ageing and the transition to AD, using tasks combining spatial memory and eye movements in immersive virtual-reality (VR) tasks. For example, one task already in development makes use of a head-mounted display with in-built eye-tracking to measure participants' gaze patterns as they observe an array of objects on a table with changes to the spatial relationships between objects. The aim will be to find markers of progressive loss of function in brain areas connected to MTL function. In addition, structural and functional MRI or MEG scanning may be used if required.