Objective: To assess cognitive and behavioral development at preschool age of children born preterm and with low birth weight and raised in a developing country.
Methods: Prospective cross-sectional study of 80 neonates born in a university hospital in southern Brazil. Neuropsychological assessment at age 4-5 years included the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), Conners' Parent Rating Scale-Revised, Denver test and neurological examination. Perinatal and early neuropsychomotor development information was collected from the database during follow-up. Results were related to birth weight, sex and gestational age.
Results: WPPSI scores were: total intelligence quotient (IQ) 88.00+/-16.96, verbal IQ 89.72+/-16.72, and executive IQ 88.12+/-15.71 for the group with less than 1,500 grams; and total IQ 91.11+/-14.73, verbal IQ 93.36+/-12.65, and executive IQ 90.20+/-16.06 for the group between 1,500 and 2,500 grams. The best scores were obtained in tests that evaluated capacity of abstraction and symbolization, picture completion and common perception, in which only 5% and 6.3% of the children had abnormal results, respectively. The lowest scores were obtained in tests that evaluated visual-motor coordination and flexibility-speed of reasoning, in which 27.5% and 16.3% of the children had abnormal results, respectively. A total of 32.5% had abnormal results in the arithmetic tests. Behaviors related to attention deficit/hyperactivity disorder (ADHD) were observed in 48% of the sample. Low score in the Bayley Mental Scale and abnormal result in the Denver test were significantly correlated to ADHD (p = 0.017 and p = 0.004). Abnormal results in the Bayley Mental Scale (p < 0.001), Denver test (p < 0.001) and neurological examination (p = 0.002) were associated with lower IQ.
Conclusions: The results revealed an increased incidence of behavioral and cognitive disorders at preschool age.