Search

When we communicate with others, we use a variety of abilities to facilitate and enable that communication. These abilities range from being responsive to others’ communicative cues to making one’s own communication more functional. Such facilitators of communication has been suggested as atypical in the development of autism. Reduced infant responsiveness towards communicative cues ­– such as speech sounds and direct gaze – have been suggested as precursors of autism. Pragmatic language use – to use language in a functional way in social interaction – is considered a core aspect of the condition later in development. In this thesis, I used diverse methodologies to study the association between these facilitators of communication and autism early in life, utilizing an infant sibling study design. In Study I, basic attentional responsivity to social and non-social sounds in infancy was tested using pupillometry. Responsivity to the non-social sounds, but not the social sounds, differentiated infants with and without subsequent autism. In Study II, infants’ behavioural responsivity to others’ direct gaze was tested in real-life interaction. Neither how much nor how quickly the infants looked towards the other person’s face after the direct gaze was reliably linked to later autism. Lastly, in Study III, two-year-olds use of pragmatic language was assessed with caregiver-questionnaires. We found a specific association between emerging pragmatic language use and dimensional autism already this early in life. The findings of this thesis suggest that infant responsivity to speech and direct gaze are not clear precursors of autism. Yet, the emerging ability to use pragmatic language seem to be linked to autism already by two years age. This thesis thus contributes to the understanding of early development of autism and how it relates to responsivity to, and use of facilitators of communication during the first years of life.

BackgroundFrom birth, infants orient preferentially to faces, and when looking at the face, they attend primarily to eyes and mouth. These areas convey different types of information, and earlier research suggests that genetic factors influence the preference for one or the other in young children. MethodsIn a sample of 535 5-month-old infant twins, we assessed eye (relative to mouth) preference in early infancy, i.e., before neural systems for social communication and language are fully developed. We investigated the contribution of genetic and environmental factors to the preference for looking at eyes, and the association with concurrent traits and follow-up measures. ResultsEye preference was independent from all other concurrent traits measured, and had a moderate-to-high contribution from genetic influences (A = 0.57; 95% CI: 0.45, 0.66). Preference for eyes at 5 months was associated with higher parent ratings of receptive vocabulary at 14 months. No statistically significant association with later autistic traits was found. Preference for eyes was strikingly stable across different stimulus types (e.g., dynamic vs. still), suggesting that infants' preference at this age does not reflect sensitivity to low-level visual cues. ConclusionsThese results suggest that individual differences in infants' preferential looking to eyes versus mouth to a substantial degree reflect genetic variation. The findings provide new leads on both the perceptual basis and the developmental consequences of these attentional biases.

BackgroundPragmatic language is key for adaptive communication, but often compromised in neurodevelopmental conditions such as autism spectrum disorder (ASD). Decontextualized language?to talk about events and things beyond here and now?develops early in childhood and can be seen as a pre-pragmatic ability. Little is known about the factors that contribute to decontextualized language use in toddlers and whether these are different from factors contributing to general language development. MethodsWe studied longitudinal associations between parent-rated core language and non-verbal socio-communicative abilities at 14 months of age, and decontextualized language use at 24 months of age in children with typical and elevated likelihood of ASD (total N = 303). Using twin modelling, we also investigated genetic and environmental contributions on decontextualized language and grammar use in two-year-old twin pairs (total N = 374). ResultsCore language ability was a strong predictor of later decontextualized language use in both children with and without an elevated likelihood of ASD. In contrast, social communication was only a significant predictor of decontextualized language use for children with low levels of core language. This pattern was specific to decontextualized language, and not replicated in prediction of concurrent grammatical ability. Further, there was a large genetic influence on decontextualized language at 2 years of age, which mostly overlapped with the genetic influences on grammatical ability. Shared environment influences were significant for grammatical ability, but not found on decontextualized language. In children with an elevated likelihood of ASD, decontextualized language use was negatively associated with autistic symptoms. ConclusionsThis study suggests that decontextualized language is developmentally associated with, yet dissociable from, more general language development measured as grammatical ability. Already at 2 years of age, parenta

Being looked at is an important communicative signal, and attenuated responses to such direct gaze have been suggested as an early sign of autism. Using live eye tracking, we examined whether direct gaze elicits different gaze responses in infants at ages 10, 14 and 18 months with and without later autism in real-life interaction. The sample consisted of 169 infants: 35 with elevated likelihood of autism and subsequent diagnosis, 94 without subsequent diagnosis and 40 with typical likelihood of autism. Infants in all groups tended to look more towards the adult’s face shortly after the direct gaze occurred. Neither how much nor how quickly the infants responded to the direct gaze differentiated the without elevated likelihood of autism and subsequent diagnosis and with elevated likelihood of autism and subsequent diagnosis groups. Infants in the typical likelihood group looked more at the face after the direct-gaze event than infants in the two elevated likelihood groups, but this result is tentative. In an exploratory analysis, infants in the elevated likelihood of autism and subsequent diagnosis group looked away quicker from faces with direct gaze than infants in the typical likelihood group, but this measure did not correlate with dimensional autism or differentiate between the two elevated likelihood groups. The current results suggest that attenuated behavioural responses to direct gaze in infancy are neither strong nor specific early markers of autism. Lay abstract When other people look directly towards us, we often respond by looking back at them, and such direct-gaze responses are important for establishing eye contact. Atypical eye contact is common in autism, but how and when this aspect of autism develops is not well understood. Here, we studied whether how much and how quickly infants respond to others’ direct gaze is associated with autism in toddlerhood. We did this by measuring direct-gaze responses in a playful social interaction using live eye tra

Background Studies of infants with an elevated likelihood of autism spectrum disorder can identify basic developmental processes that are associated with subsequently emerging clinical symptoms. Atypical responsiveness to sounds in infancy is such a potential early marker of autism. Here, we used pupillometry to quantify reactivity to social and nonsocial sounds in infants with a subsequent diagnosis. Previous research suggest that pupil dilation reflects attentional alerting, and link it to the locus coeruleus norepinephrine system. Methods We measured pupil dilation responses to child-directed speech and the sound of running water; sounds infants often hear in their everyday life. The final sample consisted of 99 ten-month-old infants (52 girls), of whom 68 had an elevated likelihood of autism and 31 were typically developing low-likelihood infants. At follow-up (36 months of age), 18 children in the elevated-likelihood group were diagnosed with autism. Results Compared to infants without diagnosis, the infants who were subsequently diagnosed with autism had larger pupil dilation when listening to nonsocial sounds, while reactivity to speech was strikingly similar between groups. In the total sample, more pupil dilation to the nonsocial sound was associated with higher levels of autistic symptoms. We also found that on a trial-by-trial basis, across all conditions and groups, more pupil dilation was associated with making fewer gaze shifts. Conclusions This study did not find evidence of atypical pupillary reactivity to child-directed speech early in life in autism. Instead, the results suggest that certain nonsocial sounds elicit atypically strong alerting responses in infants with a subsequent autism diagnosis. These findings may have important theoretical and clinical implications.

Grammatisk förmåga i skolåldern har inte utretts på ett utförligt sätt för svenskspråkiga barn. Det finns heller inga tydliga svar kring hur den grammatiska förmågan hos barn med autismspektrumtillstånd utan utvecklingsstörning (AST) ter sig i denna ålder, samt ifall denna förmåga skiljer sig från den hos barn med typisk utveckling (TU). Föreliggande studie avsåg bidra inom detta kunskapsfält genom analyser av grammatisk språkanvändning hos barn med AST (n=5) och TU (n=11) i åldrarna 9 till 12 år. Resultaten visade att det fanns en stor variation i hur barnen behärskade grammatikanvändning, vilket tolkades som att denna förmåga fortsätter att utvecklas långt upp i åldrarna. Denna utveckling går olika fort för olika barn. Utifrån den funktionella analysen av skriftliga och muntliga narrativer noterades generellt större skillnader mellan individer än mellan grupper. Gällande användning av personliga pronomen, anaforiska pronomen samt skriftlig textlängd fanns en viss skillnad mellan grupperna. En signifikant skillnad syntes mellan grupperna gällande grammatisk impressiv förmåga mätt med TROG 2, där TU-gruppen fick högre resultat än AST-gruppen. Få slutsatser kan dras från resultatet på grund av ett för litet deltagarunderlag, och studien bör främst ses som en pilotstudie samt ett utvecklande av testförfarande. Analys av muntliga och skriftliga narrativer bedöms vara en tillförlitlig metod för att bedöma grammatisk förmåga hos barn i denna ålder.