4 research outputs found
Eyetracking Metrics in Young Onset Alzheimer’s Disease: A Window into Cognitive Visual Functions
Young onset Alzheimer’s disease (YOAD) is defined as symptom onset before the age of
65 years and is particularly associated with phenotypic heterogeneity. Atypical presentations,
such as the clinic-radiological visual syndrome posterior cortical atrophy (PCA),
often lead to delays in accurate diagnosis. Eyetracking has been used to demonstrate
basic oculomotor impairments in individuals with dementia. In the present study, we
aim to explore the relationship between eyetracking metrics and standard tests of visual
cognition in individuals with YOAD. Fifty-seven participants were included: 36 individuals
with YOAD (n = 26 typical AD; n = 10 PCA) and 21 age-matched healthy controls.
Participants completed three eyetracking experiments: fixation, pro-saccade, and
smooth pursuit tasks. Summary metrics were used as outcome measures and their
predictive value explored looking at correlations with visuoperceptual and visuospatial
metrics. Significant correlations between eyetracking metrics and standard visual cognitive
estimates are reported. A machine-learning approach using a classification method
based on the smooth pursuit raw eyetracking data discriminates with approximately
95% accuracy patients and controls in cross-validation tests. Results suggest that the
eyetracking paradigms of a relatively simple and specific nature provide measures not
only reflecting basic oculomotor characteristics but also predicting higher order visuospatial
and visuoperceptual impairments. Eyetracking measures can represent extremely
useful markers during the diagnostic phase and may be exploited as potential outcome
measures for clinical trials