The geometric preference subtype in ASD: identifying a consistent, early-emerging phenomenon through eye tracking

Abstract

BackgroundThe wide range of ability and disability in ASD creates a need for tools that parse the phenotypic heterogeneity into meaningful subtypes. Using eye tracking, our past studies revealed that when presented with social and geometric images, a subset of ASD toddlers preferred viewing geometric images, and these toddlers also had greater symptom severity than ASD toddlers with greater social attention. This study tests whether this “GeoPref test” effect would generalize across different social stimuli.MethodsTwo hundred and twenty-seven toddlers (76 ASD) watched a 90-s video, the Complex Social GeoPref test, of dynamic geometric images paired with social images of children interacting and moving. Proportion of visual fixation time and number of saccades per second to both images were calculated. To allow for cross-paradigm comparisons, a subset of 126 toddlers also participated in the original GeoPref test. Measures of cognitive and social functioning (MSEL, ADOS, VABS) were collected and related to eye tracking data. To examine utility as a diagnostic indicator to detect ASD toddlers, validation statistics (e.g., sensitivity, specificity, ROC, AUC) were calculated for the Complex Social GeoPref test alone and when combined with the original GeoPref test.ResultsASD toddlers spent a significantly greater amount of time viewing geometric images than any other diagnostic group. Fixation patterns from ASD toddlers who participated in both tests revealed a significant correlation, supporting the idea that these tests identify a phenotypically meaningful ASD subgroup. Combined use of both original and Complex Social GeoPref tests identified a subgroup of about 1 in 3 ASD toddlers from the “GeoPref” subtype (sensitivity 35%, specificity 94%, AUC 0.75.) Replicating our previous studies, more time looking at geometric images was associated with significantly greater ADOS symptom severity.ConclusionsRegardless of the complexity of the social images used (low in the original GeoPref test vs high in the new Complex Social GeoPref test), eye tracking of toddlers can accurately identify a specific ASD “GeoPref” subtype with elevated symptom severity. The GeoPref tests are predictive of ASD at the individual subject level and thus potentially useful for various clinical applications (e.g., early identification, prognosis, or development of subtype-specific treatments).Electronic supplementary materialThe online version of this article (10.1186/s13229-018-0202-z) contains supplementary material, which is available to authorized users.

Comparison of three different eye-tracking tasks for distinguishing autistic from typically developing children and autistic symptom severity

“…In line with many previous studies [Moore et al, 2018;Pierce et al, 2011Pierce et al, , 2015 children in the ASD group generally spent less time looking at the display screen than ones in the TD group and thus the most effective measure for group comparisons is the relative proportion of time spent viewing one stimulus compared with another.…”

“…The proportion of the total fixation time on DSI was used as the dependent variable. In accordance with previous studies [Moore et al, 2018;Pierce et al, 2011Pierce et al, , 2015, the dependent variable was compared to Toy 2 were calculated. In all cases fixation counts and durations were also measured.…”

Children with autism observe social interactions in an idiosyncratic manner

“…It has been proposed that gaze abnormalities in children with ASD may reduce their early exposure to social information and impair their ability of learn basic social skills (Klin, Shultz, & Jones, 2015). Indeed, a common behavioral symptoms of ASD is reduced eye contact (Senju & Johnson, 2009;Tanaka & Sung, 2016) and previous eye tracking studies have reported that children with ASD exhibit weaker gaze preferences for people (Moore et al, 2018;Pierce et al, 2016), faces (Chawarska, Macari, & Shic, 2012;Chita-Tegmark, 2016;Constantino et al, 2017;W Jones, Carr, & Klin, 2008;Warren Jones & Klin, 2013;Papagiannopoulou, Chitty, Hermens, Hickie, & Lagopoulos, 2014;Riby & Hancock, 2009;Rice, Moriuchi, Jones, & Klin, 2012;Q. Wang, Campbell, Macari, Chawarska, & Shic, 2018), biological motion (Falck-Ytter, Rehnberg, & Bölte, 2013;Klin, Lin, Gorrindo, Ramsay, & Jones, 2009), and following the gazes of others (Bedford et al, 2012).…”

“…ROIs typically include the face, eyes, mouth, body, objects, or other items of potential interest (e.g., an object that is being manipulated) (Chawarska et al, 2012;W Jones et al, 2008;Warren Jones & Klin, 2013). The second estimates the relative amount of time that children gaze at each side of a split screen that contains two different stimuli (e.g., children exercising on one side and geometrical shapes on the other (Moore et al, 2018;Pierce et al, 2016)). Both of these measures estimate gaze abnormalities using summary statistics that quantify the total amount of time that a child gazes at a particular stimulus, regardless of when they gazed at it (i.e., ignoring the temporal gaze pattern).…”

“…This experimental design enabled us to compare findings across movies, presentations, and eye-tracking measures as well as quantify the gaze pattern idiosyncrasy of individual children. This is particularly important given the large heterogeneity in gaze behaviors of ASD children that is commonly reported in eye tracking studies (Campbell, Shic, Macari, & Chawarska, 2014;Moore et al, 2018;Pierce et al, 2016;Rice et al, 2012).…”