Cognitive profile in young adults born preterm at very low birthweight

Abstract

Aim: the aim of this study was to assess cognitive function at the age of 19 years in individuals of very low birthweight (VLBW; ≤ 1500g) and in term-born comparison individuals.

Method: in this hospital-based follow-up study, 55 VLBW participants (30 males, 25 females; mean birthweight 1217g, SD 233g; mean gestational age 29.1wks, SD 2.5wks) and 81 comparison individuals (42 males, 39 females; mean birthweight 3707g, SD 433g; mean gestational age 39.7wks, SD 1.2wks) were examined with a standardized IQ test (Wechsler Adult Intelligence Scale III) to assess general cognitive ability.

Results: over half (53%) of the VLBW participants achieved a low IQ score (defined as >1SD below the mean in the comparison group; odds ratio 6.4 vs comparison individuals; 95% confidence interval 2.8-14.4; p<0.001). None of the VLBW group, compared with 22% of the comparison individuals, achieved a high IQ score (>1SD above the comparison mean). VLBW participants scored lower than comparison individuals on full, verbal, and performance IQ, as well as on all four indices (p ≤0.001). The subtest profile indicated problems on all subtests, but especially on those related to arithmetic and visual-perceptual tasks.

Interpretations: few studies have undertaken a comprehensive assessment of general cognitive outcome (IQ) among young adults of VLBW. Our results indicate that VLBW seems to have a global and lasting impact on cognitive ability. Full-scale IQ assessment may reveal important learning problems in young adults of VLBW, and should be performed to inform appropriate assistance to enhance academic achievement and the chances of permanent employment as adults.