Cognitive and Academic Consequences of Bronchopulmonary Dysplasia and Very Low Birth Weight: 8-Year-Old Outcomes

Abstract

Objective. To examine the effects of bronchopulmonary dysplasia (BPD) and very low birth weight (VLBW) on the cognitive and academic achievement of a large sample of 8-year-old children. Methods. Infants who were VLBW and had BPD (n = 98) or did not have BPD (n = 75) and term infants (n = 99) were followed prospectively to age 8. Groups were compared on measures assessing 4 broad areas of functioning: intelligence, achievement, gross motor, and attentional skills. Measures included the Wechsler Intelligence Scale for Children III, the Woodcock Johnson Test of Achievement-Revised, the Bruininks-Oseretsky Test of Motor Proficiency, the Tactual Performance Test (spatial memory), and the Continuous Performance Test (attention). School outcomes were assessed by parent and teacher report, as well as from school records. Groups were comparable on socioeconomic status, sex, and race. The total sample of BPD, VLBW, and term children was compared on all outcome measures. In addition, neurologic risk was assessed in the present sample and included the following: intraventricular hemorrhage, echodense lesions, porencephaly, hydrocephalus, ventriculoperitoneal shunt, meningitis, and periventricular leukomalacia. Individual difference analyses were conducted for neurologically intact children in all 3 groups. Finally, treatment effects were examined by comparing BPD children who had received steroids as part of their treatment with BPD children who had not. Results. The BPD group demonstrated deficits compared with VLBW and term children in intelligence; reading, mathematics, and gross motor skills; and special education services. VLBW children differed from term children in all of the above areas, except reading recognition, comprehension, and occupational therapy. Attentional differences were obtained between BPD and term children only. The BPD group (54%) was more likely to be enrolled in special education classes than VLBW (37%) or term children (25%). In addition, more BPD children (20%) achieved full-scale IQ scores <70, in the mental retardation range, compared with either VLBW (11%) or term (3%) children, with all VLBW children significantly more likely than term children to achieve IQs in the subaverage category. After controlling for birth weight and neurologic problems, BPD and/or duration on oxygen predicted lower performance IQ, perceptual organization, full-scale IQ, motor and attentional skills, and special education placement. The qualitative classification of BPD (present or absent) was a significant predictor for lower scores on measures of applied problems; motor skills; and incidence of speech-language, occupational, and physical therapies. Individual difference analyses were performed to ascertain whether differences between the risk groups were primarily attributable to neurologic complications. Even with the neurologically intact sample of BPD and VLBW children, differences between the term comparison group and both the BPD and VLBW groups were found for many outcome measures. When birth weight and neurologic complications were controlled, BPD and severity of BPD were associated with lower performance and full-scale IQ, poorer perceptual organization, attention, and motor skills, as well as lower school achievement and greater participation in special education, including occupational, physical, and speech-language therapies. Treatment protocol may in part be responsible for differences observed in our BPD sample. Steroid and nonsteroid groups of BPD children differed significantly in performance IQ (72.8 vs 84.8) and full-scale IQ (77.0 vs 85.2); perceptual organization (74.0 vs 85.2); Bruininks-Oseretsky Test of Motor Proficiency score (36.6 vs 44.7); and participation in special education (78% vs 48%), occupational therapy (71% vs 44%), and physical therapy (71% vs 41%). In every instance, BPD children who received steroids fared more poorly than BPD children who did not receive steroids. Conclusions. BPD and duration on oxygen have long-term adverse effects on cognitive and academic achievement above and beyond the effects of VLBW. The problems that have been identified at 8 years of age highlight the need for continued monitoring of the learning, behavior, and development of BPD children to intervene with children who are at risk for school problems.