Webcam-Based Eye-Tracking of Attentional Biases in Alzheimer’s Disease: A Proof-Of-Concept Study

Abstract

Objectives: To measure home-based older adults’ attentional biases (AB) using webcam-based eye-tracking (WBET) and examine internal consistency. Methods: Twelve participants with and without cognitive impairment completed online self-report anxiety and depression screens, and a 96-trial dot-probe task with eye-gaze tracking. For each trial, participants fixated on a cross, free-viewed sad-neutral, sad-angry, sad-happy, angry-neutral, angry-happy, and happy-neutral facial expression pairings, and then fixated on a dot. In emotional-neutral pairings, the time spent looking (dwell-time) at neutral was averaged and subtracted from the emotional average to indicate biases “away from” (negative score) and “toward” (positive score) each emotional face. Internal consistency was estimated for dwell-times and bias scores using Cronbach’s alpha and Spearman–Brown corrected split-half coefficients. Results: The full-cohort and a comorbid anxious and depressed sub-group (n = 6) displayed AB away from sad faces, and toward angry and happy faces, with happy-face AB being more pronounced. AB indices demonstrated low reliability except sub-group happy-face indices. Happy-face AB demonstrated the highest reliability. Conclusions: AB measures were in-line with lab-based eye-tracking literature, providing some support for WBET-based measurement. Clinical Implications: Establishing the feasibility of WBET-based measures is a step toward an objective home-based clinical tool. Literature-based suggestions are provided to improve reliability.