Eye Tracking Reveals Abnormal Visual Preference for Geometric Images as an Early Biomarker of an Autism Spectrum Disorder Subtype Associated With Increased Symptom Severity.

BACKGROUND: Clinically and biologically, autism spectrum disorder (ASD) is heterogeneous. Unusual patterns of visual preference as indexed by eye tracking are hallmarks; however, whether they can be used to define an early biomarker of ASD as a whole or leveraged to define a subtype is unclear. To begin to examine this issue, large cohorts are required. METHODS: A sample of 334 toddlers from six distinct groups (115 toddlers with ASD, 20 toddlers with ASD features, 57 toddlers with developmental delay, 53 toddlers with other conditions [e.g., premature birth, prenatal drug exposure], 64 toddlers with typical development, and 25 unaffected toddlers with siblings with ASD) was studied. Toddlers watched a movie containing geometric and social images. Fixation duration and number of saccades within each area of interest and validation statistics for this independent sample were computed. Next, to maximize power, data from our previous study (n = 110) were added for a total of 444 subjects. A subset of toddlers repeated the eye-tracking procedure. RESULTS: As in the original study, a subset of toddlers with ASD fixated on geometric images >69% of the time. Using this cutoff, sensitivity for ASD was 21%, specificity was 98%, and positive predictive value was 86%. Toddlers with ASD who strongly preferred geometric images had 1) worse cognitive, language, and social skills relative to toddlers with ASD who strongly preferred social images and 2) fewer saccades when viewing geometric images. Unaffected siblings of ASD probands did not show evidence of heightened preference for geometric images. Test-retest reliability was good. Examination of age effects suggested that this test may not be appropriate with children >4 years old. CONCLUSIONS: Enhanced visual preference for geometric repetition may be an early developmental biomarker of an ASD subtype with more severe symptoms.

Detecting, studying, and treating autism early: the one-year well-baby check-up approach.

OBJECTIVES: To determine the feasibility of implementing a broadband screen at the 1-year check-up to detect cases of autism spectrum disorders (ASD), language delay (LD), and developmental delay (DD). STUDY DESIGN: The Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist was distributed at every 1-year pediatric check-up; 137 pediatricians and 225 infants participated. Screens were scored immediately, and failures referred for further evaluation. RESULTS: Pediatricians screened 10 479 infants at the 1-year check-up; 184 infants who failed the screen were evaluated and tracked. To date, 32 infants received a provisional or final diagnosis of ASD, 56 of LD, nine of DD, and 36 of "other." Five infants who initially tested positive for ASD no longer met criteria at follow-up. The remainder of the sample was false positive results. Positive predictive value was estimated to be .75. CONCLUSIONS: The 1-Year Well-Baby Check-Up Approach shows promise as a simple mechanism to detect cases of ASD, LD, and DD at 1 year. This procedure offers an alternative to the baby sibling design as a mechanism to study autism prospectively, the results of which will enrich our understanding of autism at an early age.

Preference for geometric patterns early in life as a risk factor for autism.

CONTEXT: Early identification efforts are essential for the early treatment of the symptoms of autism but can only occur if robust risk factors are found. Children with autism often engage in repetitive behaviors and anecdotally prefer to visually examine geometric repetition, such as the moving blade of a fan or the spinning of a car wheel. The extent to which a preference for looking at geometric repetition is an early risk factor for autism has yet to be examined. OBJECTIVES: To determine if toddlers with an autism spectrum disorder (ASD) aged 14 to 42 months prefer to visually examine dynamic geometric images more than social images and to determine if visual fixation patterns can correctly classify a toddler as having an ASD. DESIGN: Toddlers were presented with a 1-minute movie depicting moving geometric patterns on 1 side of a video monitor and children in high action, such as dancing or doing yoga, on the other. Using this preferential looking paradigm, total fixation duration and the number of saccades within each movie type were examined using eye tracking technology. SETTING: University of California, San Diego Autism Center of Excellence. PARTICIPANTS: One hundred ten toddlers participated in final analyses (37 with an ASD, 22 with developmental delay, and 51 typical developing toddlers). MAIN OUTCOME MEASURE: Total fixation time within the geometric patterns or social images and the number of saccades were compared between diagnostic groups. RESULTS: Overall, toddlers with an ASD as young as 14 months spent significantly more time fixating on dynamic geometric images than other diagnostic groups. If a toddler spent more than 69% of his or her time fixating on geometric patterns, then the positive predictive value for accurately classifying that toddler as having an ASD was 100%. CONCLUSION: A preference for geometric patterns early in life may be a novel and easily detectable early signature of infants and toddlers at risk for autism.