Division of Neuropaediatrics, Development and Rehabilitation, Children's University Hospital, Inselspital, 3010 Bern, Switzerland.
Eur J Pediatr. 2013 Apr;172(4):473-83. doi: 10.1007/s00431-012-1906-2. Epub 2012 Dec 18.
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.
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.
本横断面研究考察了极早产和/或极低出生体重（VPT/VLBW）的儿童与同龄足月出生的对照组在三个核心执行功能方面的表现：抑制、工作记忆和转换。根据中位数（年轻组：8.00-9.86 岁；年长组：9.87-12.99 岁）将儿童分为两个年龄组。研究的目的是调查（a）两个年龄组的 VPT/VLBW 儿童是否表现不如对照组（缺陷假说）或随着年龄的增长而赶上（延迟假说），以及（b）与对照组相比，VPT/VLBW 儿童在执行功能方面是否表现出类似的表现提升模式。研究招募了 1998-2003 年队列中出生的 56 名 VPT/VLBW 儿童和 41 名健康足月出生的对照组。所有儿童均完成了抑制测试（颜色-单词干扰任务、德克萨斯执行功能系统（D-KEFS））、工作记忆测试（数字倒背、HAWIK-IV）和转换测试（走迷宫测试、数字-字母排序、德克萨斯执行功能系统（D-KEFS））。结果表明，年轻的 VPT/VLBW 儿童在抑制、工作记忆和转换方面的表现明显不如年轻对照组，而年长的 VPT/VLBW 儿童在所有三个执行功能方面的表现与年长对照组相似。此外，在年轻的 VPT/VLBW 组中，抑制、工作记忆和转换障碍的发生率高于年轻对照组，而在年长组中，障碍的发生率是相等的。在 VPT/VLBW 儿童和对照组中，8 至 12 岁之间执行功能的最高提升是在转换方面，其次是工作记忆和抑制。
本研究提供的证据表明，（a）年轻的 VPT/VLBW 儿童在抑制、工作记忆和转换方面的表现较差可能反映了延迟而不是缺陷，以及（b）与对照组相比，VPT/VLBW 儿童在这三个执行功能方面可能表现出相似的表现提升模式。
