title: Executive functions of children born very preterm--deficit or delay?
abstract: This cross-sectional study examined the performance of children born very preterm and/or at very low birth weight (VPT/VLBW) and same-aged term-born controls in three core executive functions: inhibition, working memory, and shifting. Children were divided into two age groups according to the median (young, 8.00-9.86 years; old, 9.87-12.99 years). The aims of the study were to investigate whether (a) VPT/VLBW children of both age groups performed poorer than controls (deficit hypothesis) or caught up with increasing age (delay hypothesis) and (b) whether VPT/VLBW children displayed a similar pattern of performance increase in executive functions with advancing age compared with the controls. Fifty-six VPT/VLBW children born in the cohort of 1998-2003 and 41 healthy-term-born controls were recruited. All children completed tests of inhibition (Color-Word Interference Task, Delis-Kaplan Executive Function System (D-KEFS)), working memory (Digit Span Backwards, HAWIK-IV), and shifting (Trail Making Test, Number-Letter Sequencing, D-KEFS). Results revealed that young VPT/VLBW children performed significantly poorer than the young controls in inhibition, working memory, and shifting, whereas old VPT/VLBW children performed similar to the old controls across all three executive functions. Furthermore, the frequencies of impairment in inhibition, working memory and shifting were higher in the young VPT/VLBW group compared with the young control group, whereas frequencies of impairment were equal in the old groups. In both VPT/VLBW children and controls, the highest increase in executive performance across the ages of 8 to 12 years was observed in shifting, followed by working memory, and inhibition.
  
  
  CONCLUSIONS
  This study provides evidence that (a) poor performance in inhibition, working memory, and shifting of young VPT/VLBW children might reflect a delay rather than a deficit and (b) that VPT/VLBW children are likely to display a similar pattern of performance increase in these three executive functions compared with that of controls.
authors.affiliation: Division of Neuropaediatrics, Development and Rehabilitation, Children's University Hospital, Inselspital, 3010 Bern, Switzerland. barbara.ritter@insel.ch
authors.forename: Barbara Catherine
authors.initials: BC
authors.lastname: Ritter
authors.forename: Mathias
authors.initials: M
authors.lastname: Nelle
authors.forename: Walter
authors.initials: W
authors.lastname: Perrig
authors.forename: Maja
authors.initials: M
authors.lastname: Steinlin
authors.forename: Regula
authors.initials: R
authors.lastname: Everts
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D062071:Infant, Extremely Premature / Q000502:physiology / Q000523:psychology*; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight / Q000502:physiology / Q000523:psychology*; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D018709:Statistics, Nonparametric; D013557:Switzerland