Neurodevelopmental Outcomes of High-Risk Preterm Infants: A Prospective Study in Japan

Objectives

To determine the neurodevelopmental outcomes of very-low-birth-weight infants (VLBWIs, birth weight <1,500 g) after 9 years of follow-up.

Methods

This study prospectively recruited 224 VLBWIs born from 2003 to 2009 in Kyushu University Hospital, Japan. Comorbidities of neurocognitive impairment, epilepsy, and autism spectrum disorder or attention-deficit hyperactivity disorder (ASD/ADHD) were assessed at age 3, 6, and 9 years.

Results

Neurodevelopmental profiles were obtained from 185 (83%), 150 (67%), and 119 (53%) participants at age 3, 6, and 9 years, respectively. At age 9 years, 25 (21%) VLBWIs showed intelligence quotient (IQ) <70, 11 (9%) developed epilepsy, and 14 (12%) had a diagnosis of ASD/ADHD. The prevalence of epilepsy was higher in children with an IQ <70 at age 9 years than in those with an IQ ≥70 (44% vs 0%). In contrast, ASD/ADHD appeared at similar frequencies in children with an IQ <70 (16%) and ≥70 (11%). Perinatal complications and severe brain lesions on MRI were considered common perinatal risks for developmental delay and epilepsy but not for ASD/ADHD. Male sex was identified as a unique risk factor for ASD/ADHD.

Conclusion

These data suggest that VLBWIs showed a higher prevalence of developmental delay, epilepsy, and ASD/ADHD at age 9 years than the general population. Distinct mechanisms might be involved in the pathogenic process of ASD/ADHD from those of developmental delay and epilepsy.

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.

Survival and neurodevelopmental outcome of preterm infants born at 22-24 weeks of gestational age

BACKGROUND

The limits of viability in extremely premature infants are challenging for any neonatologists in developed countries. The neurological development and growth of extremely preterm infants have come to be the emerging issue following the management in the neonatal intensive care unit.

OBJECTIVE

To assess potential associations between changes in practice and survival/neurodevelopmental outcome, and clinical outcomes of extremely preterm infants born at the limit of viability studied in a tertiary center.

STUDY DESIGN

A retrospective study enrolled 51 infants who had no congenital disorders, and were born at 22-24 weeks of gestational age (GA) in 2000-2009 in our institution. Clinical variables and interventions were studied with regard to one-year survival and developmental quotient (DQ) at 3 years of age.

RESULTS

The one-year survival rate of 24 preterm infants born in 2005-2009 (79%) was higher than that of the 27 infants born in 2000-2004 (52%, p = 0.04). Infants born after 2005 underwent less tocolysis (54 vs. 94%, p < 0.01) and more frequently antenatal steroid therapy (32 vs. 6%, p = 0.01) than those born before 2004. The post-2005 survivors (n = 19) received more frequently indomethacin therapy (89 vs. 50%, p = 0.03) and early parenteral nutrition (95 vs. 36%, p < 0.01) than the pre-2004 survivors (n = 14). There were no differences in the proportion of infants who attained a DQ of >50 at 3 years of age between pre-2004 (9/13, 69%) and post-2005 groups (10/17, 59%). Multivariate analysis indicated that extremely premature birth at GA <24 weeks was the sole critical factor for a DQ of >50 in survivors.

CONCLUSIONS

The perinatal care after 2005 improved the overall survival rate, but not the neurological outcome of preterm survivors at the limit of viability. Neurodevelopmental impairments were associated with extremely premature birth at GA <24 weeks.

Parental age and child growth and development: child health check-up data

BACKGROUND

The aim of the present study was to determine whether parental age has any influence on child health.

METHODS

Well-baby check-up data at 1 month and at 12 months of age were used. The trends of parental age in association with growth measurements, incidence of physical and developmental abnormalities, occurrence of low birthweight, and maternal history of spontaneous abortion were analyzed.

RESULTS

Associations between increasing paternal age and incidence of psychomotor developmental delay at 12 months, increasing paternal and maternal age and increasing birthweight, and increasing parental age and higher incidence of history of spontaneous abortion were found. The incidence of low-birthweight infants was significantly decreased with increasing paternal age.

CONCLUSIONS

Not only increasing maternal age but also increasing paternal age have influences on child development and growth in the general population.

The relationship between retrieval success and task performance during the recognition of meaningless shapes: an event-related near-infrared spectroscopy study

Retrieval success of episodic memory has been studied intensively through the investigation of old/new effects. Recognized stimuli used in event-related functional magnetic resonance imaging studies on old/new effects have been words and visual materials which can evoke semantic associations. To elucidate the neural basis of retrieval success uninfluenced by semantic processing, we investigated the correlation between old/new effects and task performance during the recognition of meaningless shapes, by using event-related near-infrared spectroscopy. Forty-two right-handed subjects made recognition judgments about old (studied) or new (unstudied) meaningless shapes. The old/new effects of the shapes were positively correlated with task performance in the bilateral inferior lateral parietal cortex (ILP), but predominantly in the left ILP. This finding indicated that the ILP was directly associated with retrieval success and its lateralization was consistently left-sided irrespective of the type of stimulus.