Increased prefrontal activation in adolescents born prematurely at high risk during a reading task.

Although individuals born prematurely have subtle white matter abnormalities and are at risk for cognitive dysfunction, few studies have examined functional reorganization in these individuals. In this study we use magnetoencephalography (MEG) to examine cortical reorganization related to prematurity. Thirty-one adolescents systemically selected from a longitudinal study on child development based on gestational age, birth weight and neonatal complications (full term, low-risk premature, high-risk premature) and reading ability (good, average or poor) performed two reading-based rhyme tasks during MEG recording. Equivalent current dipoles were localized every 4 ms during the 150 ms to 550 ms period following the onset of the word presentation. The association of the mean number of dipole (NOD) with birth risk, reading ability and latency was examined. During the real-word rhyme task, adolescents born at high-risk demonstrated a greater NOD in the left prefrontal area than those born at low-risk and term. During the non-word rhyme task, good and average readers born at high-risk demonstrated a greater NOD in the left prefrontal area than good and average readers born at low-risk and term. Time course analysis confirmed increased activation in the left prefrontal regions of those born at high-risk. This study suggests that adolescents born prematurely at high-risk, as compared to those born at low-risk and term, demonstrate increased prefrontal cortical activation during a reading task. These results suggest a reorganization of the prefrontal cortex in adolescents born prematurely at high-risk.