Quantitative assessment of oral tactile sensitivity in pre-term and term neonates, and comparison with adults.

The tongues of 34 infants between 31 and 40 weeks estimated gestational age were stimulated with filament esthesiometers. Stereotyped ipsilateral movements of the tongue were elicited in all infants. An assessment of tactile sensitivity based on this reflex is minimally affected by infant activity state and habituation to repeated stimulation. Small pre-term infants (31 to 35 weeks gestation) and infants born near term (37 to 40 weeks gestation) were more sensitive to tactile stimulation than an intermediate group (35 to 37 weeks gestation). In infants followed longitudinally, a transient decrement in sensitivity occurred at two weeks postnatal age. The tactile sensitivity in 12 adults (as measured by their correct reports of stimulus location) was far greater than the sensitivity of the infants.