Hand preference develops across childhood and adolescence in extremely preterm children: The EPICure Study

Abstract Aim To determine how handedness changes with age, and its relation to brain injury and cognition in births before 26 weeks of gestation. Methods We used data from the EPICure study of health and development following birth in the British Isles in 1995. Handedness was determined by direct observation during standardised testing at 2.5, 6 and 11 years of age and by self-report using the Edinburgh Handedness Inventory at 19 years. Control data from term births were included at 6, 11 and 19 years. Results In extremely preterm children left handedness increased from 9% to 27% between 2.5y and 19y, with a progressive reduction in mixed handedness from 59% to 13%. Although individual handedness scores varied over childhood, the between-group effects were consistent through 19 years, with greatest differences in females. In extremely preterm participants, neonatal brain injury was associated with lower right handedness scores at each age and left-handed participants had lower cognitive scores at 19 years after controlling for confounders, but not at other ages. Conclusion Increasing hand lateralisation is seen over childhood in extremely preterm survivors, but consistently more have non-right preferences at each age than controls.