Development of an Objective Autism Risk Index Using Remote Eye Tracking

Abstract

Objective: Abnormal eye gaze is a hallmark characteristic of autism spectrum disorder (ASD), and numerous studies have identified abnormal attention patterns in ASD. The primary aim of the present study was to create an objective, eye tracking-based autism risk index.

Method: In initial and replication studies, children were recruited after referral for comprehensive multidisciplinary evaluation of ASD and subsequently grouped by clinical consensus diagnosis (ASD n = 25/15, non-ASD n = 20/19 for initial/replication samples). Remote eye tracking was blinded to diagnosis and included multiple stimuli. Dwell times were recorded to each a priori-defined region of interest (ROI) and averaged across ROIs to create an autism risk index. Receiver operating characteristic curve analyses examined classification accuracy. Correlations with clinical measures evaluated whether the autism risk index was associated with autism symptom severity independent of language ability.

Results: In both samples, the autism risk index had high diagnostic accuracy (area under the curve [AUC] = 0.91 and 0.85, 95% CIs = 0.81-0.98 and 0.71-0.96), was strongly associated with Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) severity scores (r = 0.58 and 0.59, p < .001), and not significantly correlated with language ability (r ≤| -0.28|, p > .095).

Conclusion: The autism risk index may be a useful quantitative and objective measure of risk for autism in at-risk settings. Future research in larger samples is needed to cross-validate these findings. If validated and scaled for clinical use, this measure could inform clinical judgment regarding ASD diagnosis and track symptom improvements.

Keywords: autism spectrum disorder; autism symptoms; objective measure; remote eye tracking; risk.

Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Effect sizes (Cohen’s d) for individual regions-of-interests (ROI) representing the magnitude of group differences between cases of autism spectrum disorder (ASD) and non-ASD cases, separately for the initial (a) and replication studies (b).

Figure 2

Areas under the curve from receiver operating characteristic curve (AUC) analysis for the autism risk index predicting consensus clinical autism spectrum disorder (ASD) diagnosis, separately for the initial (a) and replication (b) samples.

Figure 3

Relationship between autism risk index scores and Autism Diagnostic Observation Schedule – Second Edition (ADOS-2) total calibrated severity scores, separately in the initial (a) and replication (b) samples.

Figure 4

Autism risk index (ARI) score distributions for autism spectrum disorder (ASD) and non-ASD cases in the combined sample.