Normative data were obtained for 156 pre-school children’s performances on measures of muscle tone, muscle co-contraction, standing balance, prone extension posture, flexion supine posture, asymmetrical tonic neck reflex, and postrotary nystagmus. Regression analysis indicated that these combined variables accounted for only 13.5 percent of the variance of postrotary nystagmus of 145 four year olds. However, if the data are examined only for children exhibiting nystagmus that is lower than 1 standard deviation below the mean, then these variables account for 50 percent of the variance of nystagmus. Prone extension posture, standing balance-eyes closed, and muscle tone account for 37 percent of the variance within this low-nystagmus population. These results are considered in light of the author’s previous studies demonstrating that, in learning-disabled children, vestibular-proprioceptive measures can be used clinically to predict which children will respond to sensory integration therapy with changes in postrotary nystagmus. These changes, according to sensory integration theory, reflect positive responses to therapy.