Feasibility and Relevance of an Eye-Tracking-Based Assessment of Morphosyntactic Comprehension in Young Autistic Children.

Background and Aims: Autism spectrum disorder is an early-onset neurodevelopmental condition, characterized by wide heterogeneity, including in language skills. Existing morphosyntactic comprehension assessment tasks are inadequate for many autistic children, leading to low task completion rates. Challenges in the assessment of morphosyntactic comprehension in these children may result in under-informed clinical profiles and hamper in-depth exploration of language profiles in research. Our aim was to develop a passive task (requiring no overt behavior) to assess syntactic comprehension in young French-speaking autistic children. We present the creation of MOSYCAT, a linguistically meaningful intermodal preferential looking task with eye-tracking, and then focus on its feasibility, acceptability, and potential clinical relevance. Methods: MOSYCAT tests four structures of varying syntactic complexity, simple intransitive sentences, simple subject-verb-object sentences, composite past tense sentences, and sentences with direct object pronominal clitics. Children viewed two videos while they listened to a sentence that matched only one of the videos. Four eye-tracking parameters were measured during their exploration of the videos: Exploration proportion (the proportion of time spent exploring the matching video), exploration accuracy (the proportion of trials in which children explored significantly more of the matching video), orientation latency (the latency of the first saccade toward the matching video), and orientation accuracy (the accuracy of the first saccade). A first version was administered to 56 non-autistic children, and then a reduced version to 23 additional non-autistic children and 21 autistic children of varying clinical profiles. All children were aged 2;6 to 5;11, a period when syntactic performance skills typically mature, but when many autistic children are not (yet) producing sentences. Results: Feasibility and acceptability were high, including in the autistic group, and more than 85% of autistic children provided usable data. A principal component analysis on MOSYCAT parameters demonstrated that two dimensions, mainly related to accuracy (exploration proportion, exploration accuracy) and speed of response (orientation latency), captured 86% of performance variability in non-autistic children. These dimensions correlated with standardized receptive morphosyntactic measures. The eye-tracking parameters yielded normal distributions, suggesting that MOSYCAT can be used to assess morphosyntactic abilities in all children, demonstrating its clinical relevance. These parameters improved with age in the non-autistic children, suggesting that MOSYCAT is sensitive to the maturation of morphosyntactic comprehension skills. As expected, autistic children performed below the non-autistic children, yet nearly all completed the task, contrary to other tasks, suggesting that MOSYCAT can assess language comprehension in autistic children from across the autism spectrum. Conclusions and Implications: MOSYCAT, a linguistically informed tool designed to assess morphosyntactic comprehension in young autistic children using a passive, eye-tracking task, proved to be clinically relevant and feasible for young autistic children. As such, it has both clinical and research potential for use in the identification and exploration of language profiles in autism. It should be noted that the assessment was not entirely standardized. Variable lighting conditions and break durations, as well as post-hoc calibration correction, were applied. These methodological choices, some of which mirror those common in clinical practice, were made to allow for wide assessment of the autistic children, many of whom required considerable support. Although promising, MOSYCAT is not ready for direct clinical transfer at this time.