Different sensory dimensions in infancy are associated with separable etiological influences and with autistic traits in toddlerhood.

Researchers studied 285 pairs of 5-month-old twins in Sweden to understand how babies process sensory information differently. They found that babies have four main ways of responding to sensory input, each influenced by different genetic and environmental factors. When these children were reassessed at 3 years old, those who had more tactile-seeking behaviors and certain sensory sensitivities as babies showed more autism-related traits as toddlers.

This Swedish twin study examined sensory processing in 285 pairs of 5-month-old twins to understand genetic and environmental influences on different sensory dimensions. Using the Infant/Toddler Sensory Profile, researchers identified four distinct sensory processing dimensions (sensation seeking, sensation avoiding, sensory sensitivity, and low registration) that had separable genetic and environmental influences. The study found that each sensory dimension had unique genetic contributions plus some shared influences. When followed up at 36 months using autism screening measures, higher levels of tactile behaviors and certain sensory processing patterns (sensory sensitivity, sensation avoiding, and low registration) were significantly associated with increased autistic traits in toddlerhood.

Early sensory assessment at 5 months may help identify infants at higher risk for autism. Different sensory processing patterns may require distinct intervention strategies. Findings support the importance of considering sensory processing in early developmental screening and intervention planning.

Single study from one population (Swedish twins). Limited follow-up duration (36 months). Autism traits measured by screening tool rather than clinical diagnosis. No information provided about inter-rater reliability or measurement validation in this specific sample.

Infants vary significantly in the way they process and respond to sensory stimuli, and altered sensory processing has been reported among infants later diagnosed with autism. Previous work with adolescents and adults suggests that variability in sensory processing may have a strong genetic basis. Yet, little is known about the etiological factors influencing sensory differences in infancy, when brain circuits supporting social and non-social cognition are sculpted and learning about the world via sensory input largely occurs in interaction with caregivers. We analysed data from a community sample of monozygotic (MZ) and dizygotic (DZ) 5-month-old same-sex twins (n = 285 pairs, n = 158 MZ pairs, n = 150 male pairs) from the BabyTwins Study in Sweden (BATSS) using exploratory factor analysis, generalised estimating equations and multivariate twin models to delineate the phenotypic and etiological structure of individual variability across different sensory processing dimensions, as measured by the Infant/Toddler Sensory Profile.

Developmental links to later autistic traits were also assessed, as measured by total scores from the Quantitative Checklist for Autism in Toddlers at 36 months. Results suggested separability between sensory processing dimensions (i.e. sensation seeking, sensation avoiding, sensory sensitivity and low registration) at a phenotypic and etiological level, with significant contributions from additive genetics and family environment that were unique to each sensory dimension and significant but smaller contributions from shared influences. Sensory domains also showed etiological separability, with unique genetic influences to each domain, while contributions from shared environment were in part shared across domains. A higher incidence of tactile-related behaviours and behaviours associated with sensory sensitivity, sensation avoiding, and low registration were significantly associated with higher levels of autistic traits in toddlerhood.

This study provides a map of the phenotypic and etiological structure of sensory processing in infancy, which will be informative for studies of both typical and atypical development.