Cognitive outcome of early intervention in preterms at 7 and 9 years of age: a randomised controlled trial.

OBJECTIVE

Examine the effect of an early intervention programme on cognitive outcome at 7 and 9 years in children with birth weight (BW) <2000 g.

DESIGN

A randomised controlled trial of a modified version of the Mother-Infant Transaction Program.

SETTING

A single tertiary neonatal unit.

PATIENTS

146 infants were randomised into a preterm control group (74) or a preterm intervention group (72).

INTERVENTIONS

The intervention consisted of eight sessions shortly before discharge and four home visits by specially trained nurses focusing on the infants' unique characteristics, temperament, developmental potential and the interaction between infants and parents.

MAIN OUTCOME MEASURES

Outcomes were assessed with the Wechsler Intelligence Scale for Children (WISC-III).

RESULTS

Mean BWs were 1396 (429) g in the intervention group and 1381(436) g in the control group. After adjusting for the possible clustering effects of twin pairs and maternal education, there were no significant differences in WISC-III scores at age 7 or 9. The mean difference was 4.1 points (95% CI -1.5 to 9.8 points) in favour of the intervention group at 7 years and 2.2 points (95% CI -3.4 to 7.6 points) at 9 years. At 7 years, a 6.8 points difference in the Verbal Comprehension Index (95% CI 0.5 to 13.0 points) was found in favour of the intervention group. Loss to follow-up at age 7 and 9 was 11% and 14%, respectively.

CONCLUSIONS

This intervention programme did not have a sustained significant effect on overall cognitive outcomes in preterm children at age 7 and 9.

TRIAL REGISTRATION NUMBER

The trial has been registered at http://www.clinicaltrials.gov (identifier NCT00222456).