Umeå universitets logga

Background: Children born preterm have a high prevalence of long-term cognitive and behavioral disturbances. Still, studies of how preterm-twin-births may effect brain maturation and thus, contribute to long-term effects on brain-behavioral development and functions are rare.

Aim: To investigate whether brain volumes differ between twin (TPB) and singleton preterm born (SPB) and full-term born children (FTB) and associate to long-term cognitive and behavioral outcomes as well as to gestational age (GA), birth weight (BW) and head circumference (BHC) at birth.

Method: A sample of 22 twin born preterm (Mean GA=32.1, BW=1781), 23 matched singletons preterm (Mean GA=31.8, BW=1751), and 22 full-term singletons were included. All children were investigated by means of their cognition functions (WISC-IV), handedness performance index and brain volumes (3 Tesla MRI) at early school ages (M=7.8y) in 40 children (9 TPB, 10 SPB, 21 FTB).

Results: The FTB-children performed better than both TPB and SPB on cognitive performance, and showed higher IQ. Brain volumes, especially Gray matter were stronger associated with IQ in the twins. Furthermore it was found that the SPB singletons had smaller Total Brain volume and less Grey Matter than FTB. The twins showed a higher prevalence of non-right handedness associated to GA, than both SPB and FTB. Independently of birth status, GA, BW and BHC were found to correlate positively with IQ, Total Brain volume, and Gray-and White matter volumes.

Conclusion: Discordant handedness in TPB children and associations to lower GA indicate effect of twin-births on early functional laterality. The overall associations found between low GA/BW and smaller BHC at birth in preterm born and associations with lower IQ and smaller brain volumes at 8-y indicate that a very preterm birth are a higher predictor for long-term effects on brain development and cognitive performance than twin-birth per se.