The Sensory Paradox: Exploring the Positive Association Between Hyper- and Hypo-Responsivity to Sensory Stimuli in Autism and Beyond

BackgroundDifferences in sensory processing are a core feature of autism spectrum disorder. Hyper- and hyporesponsivity to sensory stimuli have historically been conceptualized as separate constructs but may co-occur within individuals. Sensory processing may impact both lower and higher-level cognitive processes; thus, it is crucial to understand the relationships between hyper- and hyporesponsivity within and across modalities, as well as the relationship between sensory processing and other aspects of development in both autistic and typically developing (TD) children. MethodsIn 3-4-year-old children (n=41 autism; n=37 TD), we assessed relationships between sensory hyper- and hyporesponsivity both within and across visual, auditory, touch, and oral sensory modalities as measured by caregiver report. Secondary analyses evaluated relationships between sensory responsivity, social communication, and cognitive abilities. FindingsWe found a positive correlation between sensory hyper- and hyporesponsivity ({rho} = .788, p < .001). These associations persisted within groups and within and across modalities. There are positive associations between sensory responsivity and social interaction, communication, and nonverbal developmental quotient, with associations between sensory responsivity and social communication driven by associations within the autism group. InterpretationThe positive correlations between hyper- and hyporesponsivity both within and across sensory modalities, which we term the "Sensory Paradox," may provide key clues to understanding sensory processing in autism and other neurodevelopmental disorders by pointing towards neural circuit-level mechanisms that may underlie neurodevelopmental conditions. FundingThis study was funded by NIH/NINDS 1R01NS134948-01 (ARL), NIMH T32MH112510 (KDC), the Simons Foundation Autism Research Initiative (Award number 648277, ARL), and the Eagles Autism Foundation (ARL). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSUp to 95% of autistic individuals are impacted by sensory processing differences. Across the full range of the autism spectrum, including individuals with profound ASD and self-advocates who speak publicly on issues of neurodiversity, improving sensory processing challenges is repeatedly noted as a common goal that would improve quality of life. Classical medical evaluation of sensory processing typically focuses on whether the structural pathways for transmission of sensory information are intact. The modulation of sensory information as it traverses these pathways, however, is a field ripe for further understanding. Initial reports have identified both hyper- and hyporesponsivity to sensory stimuli in autism, with some overlap between the two patterns of behavior. Added value of this studyThis study demonstrates the seemingly paradoxical finding that hyper- and hyporesponsivity are strongly positively correlated in both autistic and typically developing toddlers. This positive correlation persists within groups and within individual sensory modalities (sight, sound, touch, and oral), as well as across modalities. Implications of all of the available evidenceThe current findings, taken together with prior literature, support the Sensory Paradox - a framework for understanding sensory processing and the resulting sensory experience of autistic individuals which may also have key implications for a wider variety of neurological, psychiatric, and developmental conditions. Rather than considering hyper- and hyporesponsivity as static and opposing constructs, future work on the neurobiology, diagnosis, and management of sensory processing will benefit from considering the variable and context-dependent nature of sensory processing within individuals.