Postrotary nystagmus response in children with Down's syndrome.

The purpose of this study was to investigate the nystagmus response in school-age children with Down's syndrome. The 35 subjects were between 5 and 9 years of age and were enrolled in public school programs for the educable and trainable mentally retarded in the northern metropolitan areas of Utah. The Southern California Postrotary Nystagmus Test (SCPNT) was administered with slightly modified verbal instructions. Durations of nystagmus for the subjects with Down's syndrome were compared with Ayres' normative data from the SCPNT using a t-test for two independent means. Results indicated there was a significant reduction in the duration of nystagmus in the children with Down's syndrome when compared to Ayres' sample of normal children; however, there was no significant difference between males and females with Down's syndrome in duration of postrotary nystagmus.