Adults born preterm, VLBW have smaller brains, suffer from more brain abnormalities

Adults who were born preterm and at very-low birthweight (VLBW) have smaller absolute brain volumes, less grey matter, and more brain abnormalities than those born term, a recent study has found.

Seventy-nine sibling pairs of the same sex participated in the study. One sibling was born preterm and VLBW, while the other was born at term. Tesla brain magnetic resonance images (MRIs) were obtained and a blinded neuroradiologist conducted the analysis, focusing on parenchymal and structural abnormalities. The FreeSurfer software was used to conduct volumetric analysis.

MRIs were available for 78 preterm adults and 72 siblings. Structural abnormalities were more than twice as common in VLBW adults than their siblings (37.2 percent vs 12.5 percent). The most common abnormality was periventricular leukomalacia, which was likewise more frequent in VLBW adults (15.4 percent vs 2.8 percent).

Linear mixed models were constructed to calculate mean differences in brain volumes and showed that total (difference, –13,240 mm³, 95 percent confidence interval [CI], –24,750 to –1,900; p<0.01) and total grey matter (difference, –10,950 mm³, 95 percent CI, –18,420 to –3,490; p=0.01) volumes were significantly smaller in VLBW adults. The same was true for the cerebellum (p=0.04), while ventricles were larger in VLBW adults (p<0.01). White matter volume did not differ between groups.

“Because our study excluded individuals with cerebral palsy and major sensorimotor disabilities, we expected the most severe forms of brain differences to be absent from our population. Our findings in the nonaffected participants may thus represent a conservative estimation of the whole VLBW adult population,” the researchers said.