Late neuropsychological outcomes in preterm infants of normal IQ: selective vulnerability of the visual system.

Evaluated neuropsychological outcomes in 635 children, ages 7 to 10 years, in relation to birth weight group: < or = 1,000 g; 1,001-1,500 g; 1,501-2,500 g, and > 2,500 g. The prevalence of low IQ (< 85) was related to birth weight. Among children with IQ > 84 (N = 475): (a) Birth weight was unrelated to Verbal IQ, Performance IQ, Full-scale IQ, or reading achievement; (b) extremely low birth weight (ELBW) children achieved more poorly in mathematics than did other birth weight groups (p < .05); (c) ELBW and very low birth weight children performed more poorly on the Rey-Osterrieth Complex Figure, a complex visual processing task, than did heavier birth weight children (p < .05), but performance on the Beery Test of Visuomotor Integration was not related to birth weight. Results are consistent with heightened neurobehavioral vulnerability of visual processing to preterm birth.