Although animal studies have indicated that general anesthetics may result in widespread apoptotic neurodegeneration and neurocognitive impairment in the developing brain, results from human studies are scarce. We investigated the association between exposure to surgery and anesthesia for inguinal hernia repair in infancy and subsequent academic performance.
Using Danish birth cohorts from 1986-1990, we compared the academic performance of all children who had undergone inguinal hernia repair in infancy to a randomly selected, age-matched 5% population sample. Primary analysis compared average test scores at ninth grade adjusting for sex, birth weight, and paternal and maternal age and education. Secondary analysis compared the proportions of children not attaining test scores between the two groups.
From 1986-1990 in Denmark, 2,689 children underwent inguinal hernia repair in infancy. A randomly selected, age-matched 5% population sample consists of 14,575 individuals. Although the exposure group performed worse than the control group (average score 0.26 lower; 95% CI, 0.21-0.31), after adjusting for known confounders, no statistically significant difference (-0.04; 95% CI, -0.09 to 0.01) between the exposure and control groups could be demonstrated. However, the odds ratio for test score nonattainment associated with inguinal hernia repair was 1.18 (95% CI, 1.04-1.35). Excluding from analyses children with other congenital malformations, the difference in mean test scores remained nearly unchanged (0.05; 95% CI, 0.00-0.11). In addition, the increased proportion of test score nonattainment within the exposure group was attenuated (odds ratio = 1.13; 95% CI, 0.98-1.31).
In the ethnically and socioeconomically homogeneous Danish population, we found no evidence that a single, relatively brief anesthetic exposure in connection with hernia repair in infancy reduced academic performance at age 15 or 16 yr after adjusting for known confounding factors. However, the higher test score nonattainment rate among the hernia group could suggest that a subgroup of these children are developmentally disadvantaged compared with the background population.
The intellectual, psychoeducational, and functional status of a regional cohort of extremely low birth weight (ELBW) survivors who weighed 501 to 1000 gm at birth (n = 143) and who were born between 1977 and 1981 was compared with that of control children born at term (n = 145) who were matched for gender, age, and social class. One hundred twenty-nine ELBW survivors (90%) were available; their mean birth weight was 839 +/- 124 gm and mean gestational age 27 +/- 2.1 weeks, and 48 of them weighed less than or equal to 800 gm at birth. Both ELBW and control groups were tested at a mean unadjusted age of 8 years; 113 of 129 ELBW children completed the full test battery, eight blind children had other tests, and eight were not testable. The mean Full Scale IQ (Wechsler Intelligence Scale for Children--Revised) was 91 +/- 16 for ELBW children and 104 +/- 12 for control children (p less than 0.0001). Between 8% and 12% of the ELBW group scored in the "abnormal" range (less than or equal to -2 SD) on the Wechsler IQ and subtests, compared with 1% to 2% of the control group. The ELBW group did less well on the reading, spelling, and mathematics tests (Wide Range Achievement Test--Revised less than or equal to -2 SD: ELBW = 20% to 28%; control = 3% to 10%). The motor performance of the ELBW group (Bruininks-Oseretsky Test of Motor Proficiency less than or equal to -2 SD: ELBW = 20%; control = 1%) and their visual-motor integration (Beery Developmental Test of Visual-Motor Integration less than or equal to -2 SD: ELBW = 21%; control = 6%) were also poorer. Exclusion of 19 ELBW children with neurologic impairments or an IQ less than or equal to 70 or both did not result in significant improvement in Wechsler or achievement measures. Approximately 15% of the ELBW cohort performed in the abnormal range on the Vineland Adaptive Behavior Scales, compared with none of the control group. Although approximately two thirds of the ELBW group were performing in the normal range on intellectual measures, comparison with the control group suggests that, as a group, ELBW children were significantly disadvantaged on every measure tested.
To examine relative age and birth place effects in hockey players drafted to play in the National Hockey League (NHL) between 2000 and 2005 and determine whether these factors influenced when players were chosen in the draft.
1013 North American draftees were evaluated from the official NHL website, which provided birthplace, date of birth and selection order in the draft. Population size was collected from Canadian and American census information. Athletes were divided into four quartiles on the basis of selection date to define age cohorts in hockey. Data between the Canadian and American players were also compared to see if the optimal city sizes differed between the two nations.
Relative age and birthplace effects were found, although the optimal city size found was dissimilar to that found in previous studies. Further, there were inconsistencies between the Canadian and American data.
Contextual factors such as relative age and size of birthplace have a significant effect on likelihood of being selected in the NHL draft.
119 Swedish children were followed from their first year of life up to the age of 8. Most could be classified according to (a) type of day-care they had experienced during their first 7 years of life and (b) time of first entrance into day-care. At 8 years, the children were tested with aptitude tests and rated by their teachers on school performance and social and personal development. Hierarchical regression analyses and MANCOVAs were used in the statistical treatment. Time of entrance into day-care predicted children's cognitive and socioemotional development, controlling for sex and home background. Children with early day-care (entrance before the age of 1) were generally rated more favorably and performed better than children with late entrance or home care. There was a tendency for early center care to predict a more favorable outcome than other care.
Forty-five left-handed and 46 right-handed 10-year-old children were subjected to a limited set of neurological tests and a square tracing task. 'Pathological' handedness was diagnosed in cases showing poor performance with the non-preferred hand on the squares task. The frequency of left-handedness in the population was estimated at 9.2%. The boy : girl ratio was 1.6:1. 'Pathological' handedness was twice as common among left-handers as among right-handers. Neurological dysfunction was more common in 'pathological' handers, especially left-handers. Reduced pre-. peri- and neonatal optimality was seen in boys with 'pathological handedness'. School achievement problems and behaviour problems were much more common in left-handed boys than in other study groups. The results lend partial support for the extended pathological left-handedness model recently hypothesized by Bishop, but it is suggested that left-handedness in boys is more often a symptom of pathological shift of handedness than is left-handedness in girls.
The study is a 12-year follow-up of all risk-children (652) and a random sample of control-children (626) born during 1968 in a delimited geographical area (Aarhus county). Information from the infancy period was obtained from the health nurses' schematic records and were concerned with family background variables, life events which had occurred during the first year of life, perinatal risk-factors and indices of health care during the first year of life. Information at 12 years of age was obtained through the records in the school health service. Multivariate predictor analyses were performed. Significant educational difficulties, which 16.6% experienced, were pronouncedly predicted from indices of low socio-economic status, child abuse and neglect and male sex. The prevalences at 12 years of age of mental disorders psychosomatic (6.7%), behaviour disorder (3.3%), and mental retardation (1.3%) were predictable from indices of social and psychosocial stress including the health nurses' assessment of inadequate care during infancy period, but with some differences among the diagnostic groups. The results show that unfavourable social factors, psychosocial stress and inadequate care are informative variables for delimitation of risk-groups in infancy.