Novel Measures of Sensory Reactivity in Early Infancy

/ABSTRACT Sensory processing difficulties are one of the biggest challenges to daily life for individuals with autism spectrum disorder (ASD). Sensory reactivity can be considered a biological response to sensory stimuli, for which individuals can vary continuously from low to high responses, for example in terms of heart rate reactivity or neural responses. We hypothesize that sensory over-responsivity (SOR), an extreme negative behavioral or affective response to everyday stimuli, emerges from early alterations in sensory reactivity and may be detected in the first six months of life. Understanding and identifying SOR emergence early in life has important implications for early intervention and limiting the extent to which SOR impairs other key developmental processes, such as social and language development, participation in school and the community, and overall well-being. Yet very few standardized, behavioral measures of SOR exist across the lifespan, and to our knowledge, no such measure exists for infants in the first 6 months of life, when these essential functions are in a key period of development. We propose to fill this critical research gap by identifying physiological (heart rate) responses to sensory stimuli and testing our hypothesis that atypical biological sensory reactivity is present and measurable before clear behavioral responses to sensory stimuli emerge. First, we will examine two existing datasets to: 1) identify candidate physiological markers of SOR in 3-month-old infants at low (LL) and elevated (EL) familial likelihood for ASD and 2) examine longitudinal changes in behavioral responses to sensory stimuli during a standardized sensory task in LL and EL infants between 6-24 months. Then, we will develop and pilot a series of standardized, naturalistic prompts that can be used to study physiological responses to aversive sensory stimuli in the first 6 months of life. Identification of physiological markers of SOR in the first 6 months would promote earlier detection of atypical development, with implications for supporting infants with atypical sensory reactivity much earlier in life, before the core features of ASD emerge. Project Number: 1R03MH141404-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Mental Health (NIMH) | Principal Investigator: Jessica Bradshaw (+1 co-PI) | Institution: UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA, COLUMBIA, SC | Award Amount: $163,395 | Activity Code: R03 | Study Section: Special Emphasis Panel[ZRG1 BP-S (02)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11216596