NEUROPSYCHOLOGIC FUNCTION IN SAME-SEX TWINS DISCORDANT FOR PERINATAL BRAIN-DAMAGE

We studied childhood neuropsychologic function in two pairs of low bir th weight, same-sex twins reared together but with different patterns of concordance and discordance for intraventricular hemorrhage (IVH) a nd hydrocephalus (HYD). Same-sex twins have discordant levels of cogni tive skills when one twin but not the other develops IVH alone or IVH and HYD at birth. The results bear on several issues: the effects of p rematurity, the effects of IVH, the combined effects of IVH and HYD, a nd the potential applications of the present methodology of pairwise-m atched twin comparisons for understanding how different forms of perin atal brain damage affect childhood cognitive functions important for l earning.