Development of nystagmus in response to vestibular stimulation in infants.

Nystagmus in response to perotatory stimulation by torsion swing or ice-cold caloric (ICC) irrigation of the ear canals was studied in 276 infants from birth to 12 months of age. The percentage of positive responses to perotatory stimulation correlated with gestational age and weight at birth during the first 3 months of life and became comparable among groups by 6 months of age. The quality of perotatory nystagmus did not differ among groups. A direct correlation between the caloric-induced intensity and duration of nystagmus with gestational age and weight at birth was noted during the first 3 months of life. Premature infants showed the weakest responses, and term-delivered, large for gestational age children the strongest responses. ICC-induced nystagmus reached comparable levels for all groups by 6 months except for premature infants, in whom comparable responses were attainedby 9 months of age. Vestibular responses mature over time, with patterns that correlate with gestational age and weight at birth.