Normative comparison of the Southern California postrotary nystagmus test: Los Angeles vs. Syracuse data.

A normative comparison was carried out on the Southern California Postrotary Nystagmus Test. Two hundred and twenty two (222) children, ages five to nine, from Syracuse, New York, were compared with the original Los Angeles sample of 226. In analyzing the Syracuse data, no significant differences were found in duration of postrotary nystagmus by age, sex, or age/sex interaction. Comparison of the Syracuse with the Los Angeles data revealed significantly different means and standard deviations, with the effect that the cut-off point for diagnosing prolonged nystagmus shifted upward. It was concluded that postrotary nystagmus is a consistent measure unaffected by age or six in normal five- to nine-year-olds, but that in view of the differences between the Syracuse and Los Angeles data, care should be taken in diagnosing prolonged postrotary nystagmus.