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.

BackgroundTo date no study has attempted to continuously evaluate changes in hemodynamics during delayed cord clamping in humans. We aimed to demonstrate 1. the feasibility of measurements of hemodynamics during delayed cord clamping and 2. to describe the changes that occur over each minute.ResultsAfter vaginal delivery, term infants (370-416 weeks) were placed on a Life Start® bed 10–20 cm below the placenta. Transcutaneous sensors were placed on the neck and chest to determine heart rate, stroke volume and cardiac output at each beat. Once a signal was obtained, first 5 values (taken every beat) were averaged and the percent change for each subject from baseline was calculated. 20 infants were enrolled and all had a reliable signal obtained from transcutaneous sensors and had a delay in cord clamping for about 5 minutes. Cardiac output increased from 2 to 5 minutes of life (p = 0.008). For every minute of life the cord was kept unclamped, the stroke volume increased 13.1% ± 12.3 (p = 0.0001) and cardiac output increased 12.6% ± 6.3 from baseline (p < 0.0001). While the majority of infants continued to have an increase in cardiac output at 5 minutes of life, 7/20 infants reached their peak cardiac output at 188 ± 41 seconds of life.ConclusionsThis study demonstrates that hemodynamic measures could be successfully obtained during the first five minutes of birth and while a newborn was receiving delayed cord clamping. This study also provides reference values for changes in cardiac output and stroke volume in well term infants during delayed cord clamping.Trial registrationClinical Trials.gov NCT02195037 Registered 17 July 2014

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