Postnatal cerebral maturation in Down's syndrome children: a developmental EEG coherence study.

Eyes-closed EEG was recorded from 19 scalp locations in thirty Down's Syndrome children and young adults, aged 9 months to 26 years. These subjects were age-matched to normal children and normal young adults. EEG coherence was computed for five groups of electrode pairings: 1--anterior-to-posterior, 2--posterior-to-anterior, 3--posterior temporal, 4--anterior temporal and 5--interhemispheric. The results showed that EEG coherence strongly and consistently discriminated between the two groups. Developmental trajectories in the Down's group were weakly linear and often with negative slopes. In contrast, normal children showed strong linear and nonlinear developmental trajectories with only positive slopes. The greatest differences between groups was in the left hemisphere and in posterior cortical regions as compared to frontal regions. The normal children exhibited growth spurts in EEG coherence at particular postnatal ages, whereas the Down's Syndrome children failed to exhibit strong growth spurts in EEG development.