All issues > Volume 47(5); 2004

Original Article

Korean J Pediatr. 2004;47(5):496-504. Published online May 15, 2004.

The Relationship between Developmental Quotient in Children with Delayed Language Development and Later Intellectual Quotient

So Yeon SY Kim¹, Yeon Kyung YK Jung¹, Hai Lee HL Jung¹, Woo Taek WT Kim¹, Im Hee IH Shin², Jung Han JH Park³, Heng Mi HM Kim⁶, Jin Kyung JK Kim¹

¹Department of Pediatrics, College of Medicine, The Catholic University of Korea, Daegu, Korea
²Department of Biostatistics, College of Medicine, The Catholic University of Korea, Daegu, Korea
³Department of Preventive Medicine, College of Medicine, The Catholic University of Korea, Daegu, Korea
⁶Department of Pediatrics, College of Medicine, Kyungpook University , Daegu, Korea

Correspondence Jin Kyung JK Kim ,Email: kimjk@cu.ac.kr

Abstract

Purpose
: The objective of this study was to test the predictive validity of developmental test for later intellectual development in young children with delayed language development.
Methods
: The study subjects were 66 children who had presented delayed language development and had an initial developmental test and a follow-up intelligence test. The mean age at initial test was 34.2 months(17-48 months), and the mean age at the follow-up test was 55.0 months(40-79.5 months).
Results
: According to CAT DQ(Cognitive Adaptive Test Developmental Quotient), 66 children were divided into 4 groups: group I(CAT DQ<50), group II(50-69), group III(70-84), and group IV(≥85). There was a moderate correlation between CAT DQ and later total IQ in group I(r=0.58) and II(r= 0.50), but a low correlation in group III(r=0.19) and IV(r=-0.16). IQs in follow-up tests of all children in group I and II were lower than 70, except two children whose IQs were 75 and 78. IQs of children in group III were lower than 85 except for three children whose IQs were 89, 89, and 90, respectively.
Conclusion
: The findings of this study suggest that if DQ is lower than 70, the child is highly probable to be mentally subnormal in later years. Although the correlation between CAT DQ and later total IQ is low in children with DQs over 70, if a DQ is between 70 and 84, the child is very likely to have learning disability in later years.

Keywords :Language delay, Developmental quotient, Intelligence quotient