Date Presented 04/21/2023

This study explored observed sensory hypo- and hyperreactivity in infants ages 2 to 18 months during play with their mothers. Infants demonstrated increases in hyporeactivity and decreases in hyperreactivity across five ages from 2 to 18 months.

Primary Author and Speaker: Cristin M. Holland

Contributing Authors: John Sideris, Pat Levitt, Barbara L. Thompson, Grace Baranek

PURPOSE: Sensory reactivity within daily activities has not been well investigated down to early infancy. This study explored the development of hyper-reactivity and hypo-reactivity responses in infants during play with their mothers from 2 to 18 months of age.

DESIGN: The sample was part of a larger longitudinal study where fifty-six mother-infant dyads were recruited from a community pediatric practice serving a diverse population.

METHOD: Infant sensory reactivity was behaviorally coded during 2-minutes of mother-infant play at 2, 6, 9, 12, and 18 months of infant age. Hyper-reactivity was evidenced by withdrawal, aversion or avoidance behaviors. Hypo-reactivity was defined as lack of or delay in orienting or disengagement. Frequency and duration of hypo- and hyper-reactivity were totaled across 2-minutes of play at each timepoint. Descriptive statistics, analysis of covariance, and growth trajectories were conducted to describe changes in observed reactivity of infants across 2 to 18 months.

RESULTS: Frequency of hypo-reactivity incidences increased from early infancy to later infancy at 9, 12, and 18 months, but duration did not change significantly across any timepoint. Both frequency and duration of hyper-reactivity incidences decreased from 2 and 6 months to later infancy at 9, 12, and 18 months. The trajectory of hypo-reactivity frequency, but not duration, demonstrated significant growth across 2 to 18 months (p < 0.01). Growth trajectories of hyper-reactivity could not be estimated.

CONCLUSIONS: Infants demonstrate changes in both observed hypo- and hyper-reactivity across 2 to 18 months during play, which could impact their ability to engage with the environment and their caregivers. Probing sensory reactivity in early infancy could provide insight into how environmental and social cues are processed, and practitioners could promote optimal engagement between infants and their environments and caregivers very early in neurodevelopment.


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