Tadahiro Kanazawa

Preschool children's behavioral tendency toward social indirect reciprocity.

Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers’ prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers’ prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children’s prosocial behavior. In other words, observing peers’ prosocial behavior toward third-party peers evoked bystanders’ positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander’s prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler’s behavioral tendency toward social indirect reciprocity in natural interactions with peers.

Long-term alpha-tocopherol supplements may improve mental development in extremely low birthweight infants.

Methods to improve the mental development of extremely low birthweight (ELBW) children are currently lacking. We assessed the effects of long‐term supplementation of alpha‐tocopherol on the neurological development of 259 school‐aged ELBW children.

Perinatal factors associated with long-term respiratory sequelae in extremely low birthweight infants

Objective To assess lung function at 8 years old in extremely low birthweight (ELBW) survivors and to identify perinatal determinants associated with impaired lung function. Design Retrospective cohort study. Setting Level III neonatal intensive care unit. Patients ELBW survivors born in 1990–2004 with available spirometry at 8 years old were studied. Children were excluded if they had a Wechsler Intelligence Scale for Children Third Edition full IQ <70. Main outcome measures Multivariate logistic regression analysis was used to identify perinatal determinants associated with airway obstruction (forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio <80%) at school age and the predictive power of potential determinants. Potential risk factors and predictors assessed in this study were gestational age, birth weight, small for gestational age, sex, chorioamnionitis, premature rupture of membranes, antenatal steroids, surfactant administration, respiratory distress syndrome, postnatal steroids, severe bronchopulmonary dysplasia and bubbly/cystic appearances of the lungs by X-ray during the neonatal period. Results Of 656 ELBW survivors, 301 (45.9%) had attended a school-age follow-up at 8 years old. A total of 201 eligible children completed the lung function test. Bubbly/cystic appearance of the lungs (OR 4.84, 95% CI 1.26 to 18.70) was associated with a low FEV1/FVC ratio. Children with bubbly/cystic appearance had characteristics of immaturity and intrauterine inflammation. Conclusions Within a cohort of ELBW infants, a bubbly/cystic appearance of the lungs in the neonatal period was the strongest determinant of a low FEV1/FVC ratio at school age.

Intelligence and Learning Disabilities in 6- to 8-year-old Children Weighing under 1000 Grams at Birth

Intellectual ability and learning disabilities (LD) were assessed in a cohort of 33 extremely low-birthweight (1000 grams) children at 6-8 years of age with a psychometric test battery. The children were classified into the following three groups: a LD-suspected group of 9 boys (27.3%), a mentally delayed group of 3 boys and 3 girls (18.2%), and a typically developing group of 6 boys and 11 girls (51.5%). No correlation was found between birthweight and intelligence quotient (IQ) at 6-8 years of age. A negative correlation was found between IQ and gestational age (GA) at a nearly significant level. The mean verbal IQ for the 11 small for gestational age (SGA) children was significantly lower than that of the appropriate for gestational age (AGA) children. The LD-suspected group was characterised by lower scores on spatial relationships and rapid but inaccurate solving of the visuo-motor integration tasks on the Frostig test.

Physical fitness of non-disabled school-aged children born with extremely low birth weights

BACKGROUND The assessment of long-term outcomes in survivors born with extremely low birth weights (ELBWs) has become increasingly important. However, little has been reported on the physical fitness of non-disabled school-aged children born with ELBWs. AIMS To assess the physical fitness of non-disabled school-aged children born with ELBWs. STUDY DESIGN Retrospective cohort study. SUBJECTS We analyzed 169 ELBW infants without cerebral palsy or intellectual disability (based on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) Full Scale intelligence quotient (IQ) test < 70). OUTCOME MEASURES Physical fitness was assessed using the grip strength, sit-up repetitions, sit & reach, side steps, standing long jump, and softball throw tests. T-scores were calculated using national survey data. RESULTS The T-scores for the grip strength, sit-up repetitions, sit & reach, side steps, standing long jump, softball throw tests, and the overall T-score were 43.7 ± 7.5, 44.2 ± 10.5, 46.0 ± 9.7, 40.9 ± 8.0, 40.0 ± 9.8, 42.4 ± 8.1, and 42.9 ± 5.5, respectively. After adjusting for other age-related factors, the height (SD score), WISC-III Performance IQ score, and percent predicted forced vital capacity (FVC) independently predicted the overall T-scores. Their standardized partial regression coefficients (β) were 0.334 (p = 0.009), 0.190 (p = 0.022), and 0.187 (p = 0.032), respectively. CONCLUSIONS Our cohorts physical fitness at approximately 8 years of age was significantly impaired compared to average Japanese children of the same age. Height, FVC, and Performance IQ independently predicted physical fitness, with height being the strongest predictor.