1. Extremely premature (EP) and extremely low birth weight (ELBW) infants born in the early 2000s have worse executive function outcomes when compared to term-matched controls than do children born in the early and late 1990s.
2. Specifically, children born in the late 2000s were found to have worse outcomes in the domains of working memory and in the skills of planning and organizing when compared to term-matched controls.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Advances in neonatal care have led to increased survival rates among infants born extremely premature (EP) and those born at extremely low birth weights (ELBW). Despite this progress long-term outcomes for this vulnerable population continue to be unlcear. In this study, researchers compared cognitive outcomes at age 7-8 for children born EP or categorized as ELBW during the early 1990s, late 1990s, and early 2000s as compared to age-matched controls. Using a combination of blinded physician assessors with standardized measures and a previously validated parental survey, researchers evaluated a number of cognitive domains including working memory, planning and organizing, impulse control, regulating emotions, attention, and achieving goals among ELBW/EP children and term-matched controls. Children born in the early 2000s were found to have higher rates of executive functioning deficits when compared to a control group than did children born in the early or late 1990s. Specific differences arose in the areas of working memory and planning and organization. Despite these significant findings, it is unclear why these differences have occurred, highlighting the importance further study on the topic.
In-Depth [prospective cohort]: In this study, researchers enlisted children characterized as EP (GA <28 weeks) or ELBW (birth weight (BW) of < 1000 g) in Victoria, Australia during 3 different time periods: 1991 to 1992, the year 1997, and the year 2005, with randomly selected controls born at ≥ 37 weeks gestation and/or with a BW of ≥ 2500 g. Researchers focused on outcomes at ages 7 to 8 years, with greater than 80% retention for all cohorts. On follow up, patients were assessed by blinded pediatricians and psychologists. Standardized measures such as Wechsler Intelligence Scale for Children, Third Edition (1991–1992 cohort) and Fourth Edition (1997 cohort), and the Differential Ability Scales, Second Edition (2005 cohort) were used. Parents were given the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire to assess areas such as emotion regulation, task completion, working memory, and planning and organizing. A greater difference in working memory scores between the EP/ELBW groups and the control groups was noted in the 2005 cohort compared with the 1991 to 1992 cohort (adjusted interaction: p = .04). In regard to planning and organizing, the 2005 cohort also more greatly differed from controls when compared with 1991 to 1992 and 1997 cohorts (adjusted interaction: p = .04 and p = .052, respectively).
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