Postrotatory nystagmus in the full-term and premature infant.
Postrotatory nystagmus (PR-N) is an easily elicited reflex reported to be abnormal in developmentally delayed children. PR-N has been recorded in newborns, but methodological difficulties have compromised its full understanding. Eight healthy adults were compared with 15 full-term and 12 premature infants, all neurologically normal, who were tested serially during the first year of life. All subjects were positioned in a rotational chair, spun for 1 min at a constant angular velocity (150 degrees/s) and then abruptly stopped. Primary and secondary PR-N was electronically recorded. Results for full-terms and prematures were similar in all variables, but the number and frequency of beats in both primary and secondary PR-N were significantly greater in adults. Angular displacement and velocity of each beat was significantly higher in infants of all ages. All components of PR-N, whether primary or secondary, can be identified in infants under 1 year of age and are clearly different from those observed in adults. These differences may reflect anatomical and neurophysiological immaturity of eye movement control in the infant.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004584:Electronystagmography; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D009760:Nystagmus, Physiologic; D010812:Physical Stimulation