The Development of Sensory Functions in Infants

The Test of Sensory Function in Infants (TSFI), a 24-item test designed to measure sensory processing and reactivity in infants, was administered to 196 normal infants, 27 infants with developmental delay, and 27 infants with difficult temperament from 4 to 18 months of age. The development of sensory functions in infants was explored for the normal sample. Developmental trends are reported for both individual items and subtest performance across the age ranges tested. Tactile deep-pressure and reactivity to vestibular stimulation were found to develop very early in infancy while visual-tactile integration, adaptive motor responses, and ocular-motor control develop gradually over the first year of life. The performance of developmentally delayed and difficult temperament infants on the TSFI was also described. Tactile defensiveness, poor ocular-motor control, and vestibular dysfunction occurred in substantial proportion of both sample. Difficulties in visual-tactile integration and adaptive motor responses were present in both samples, but to a lesser degree. The overall incidence of sensory processing dysfunction was approximately 55% to 85% in both samples for 7- to 18-month-old infants.