Median coherence and coherograms in age groups. (A, E) 4 months to 1 yr. The median coherence and coherogram show faint slow (0.1 to 1 Hz) coherence, but no significant frontal coherence is observed overall. (B, F) Greater than 1 to 7 yr. The median coherence and coherogram exhibit some slow coherence and significant alpha (8 to 13 Hz) coherence. (C, G) Greater than 7 to 14 yr. The median coherence and coherogram show a relative increase in slow coherence, and prominent alpha coherence. (D, H) Greater than 14 to 21 yr. The median coherence and coherogram show a significant increase in slow coherence and a relative decrease in alpha coherence. Statistically significant differences between age groups can be found in table 3.