Language assessment of non-handicapped twins at 5 years of age

Abstract

Background: The aim of the present study was to determine language levels in twins and singletons born after at least 34 weeks gestation and without identifiable neurological abnormality and to evaluate whether in vitro fertilization (IVF) affects language development in twin pregnancies.

Methods: A prospective study of a large cohort of all children born between 1 January 2001 and 31 December 2003 was carried out at Gazi University Hospital. All live-born twin pairs in which both twins survived were identified, and a comparable sample of families with pairs of singletons were chosen. The Stanford-Binet Intelligence Scale Form and the translated Turkish form of the Peabody Picture Vocabulary Test were completed at 60 months.

Results: Even after excluding the most premature twins and those with diagnosable neurological damage, twins performed worse than singletons on language development tests. Twin girls had better scores than twin boys. A statistically significant difference was found between the scores of term and preterm twins. No significant difference was noted when compared according to birth order. Appropriate for gestational age (AGA) twins did better than small for gestational age (SGA) twins in the test scores. All twin girls did not differ from singleton girls, but all twin boys performed worse than singleton boys. Term twins had similar results with term singletons, but preterm twins had lower scores than preterm singletons. SGA singletons had better scores than SGA twins, while AGA twins and singletons did not differ. When the children were compared with regard to method of conception, IVF children had significantly lower scores on the tests than those in the spontaneous conception group.

Conclusion: It is hoped that the present findings could lead to a more precise assessment of children for speech impairment and, above all, to more efficient preventive intervention. Whatever mechanisms are involved, the present results indicate that twins born as a result of IVF, are at a disadvantage in terms of language development in comparison with spontaneously conceived twins.