Longitudinal study of very low birth weight infants until 9years of age; attention deficit hyperactivity and autistic features are correlated with their cognitive functions.

Background: Increasing attention has been given to neuro-developmental problems of very low birth weight infants (VLBWIs) at school age. However, it remains unknown whether their neuro-cognitive function and psychiatric symptoms are mutually associated.
Aim: The aim of this study was to investigate the characteristics of neuro-cognitive functions in VLBWIs and their relationship with psychiatric symptoms.
Methods: A total of 160 VLBWIs who were born at our institute between 2001 and 2005 were recruited consecutively and followed up until nine years of age. The developmental profiles were obtained from 77 children (45 males and 32 females) at six to nine years of age using the ADHD Rating Scale-Fourth edition (ADHD-RS), Autism Screening Questionnaire-Japanese version (ASQ-J) and the Wechsler Intelligence Scale for Children-Third edition (WISC-III).
Results: The full-scale intelligence quotient did not significantly differ between the male and female VLBWIs (median: 91 vs. 99, p=0.17). The males had higher total scores (median: 13 vs. 4, p<0.01) and higher scores on the subscales of Inattention (8 vs. 2, p<0.01) and Hyperactivity-Impulsivity (5 vs. 1, p<0.01) of the ADHD-RS compared with the females. The Verbal Comprehension Index (VCI) of the WISC-III was inversely correlated with the total scores of the ASQ-J for all VLBWIs (n=77, rc: -0.32, 95% CI: -0.19 to -0.01, p=0.04). We also observed that the Freedom from Distractibility Index (FDI) of the WISC-III was significantly correlated with the Inattentive scores of the ADHD-RS (n=45, rc: -0.18, 95% CI: -0.35 to -0.02, p=0.03) in male, but not female VLBWIs.
Conclusions: We herein report that the VCI and FDI of the WISC-III were correlated with the autism spectrum disorder and attention deficit hyperactivity disorder symptoms, respectively, in male VLBWIs.
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