Electroencephalographic sleep of healthy children. Part II: Findings using automated delta and REM sleep measurement methods.

Using earlier developed computer-based measurement methods, delta and REM activity were examined during sleep as a function of age, gender, and time of night in 85 healthy, 6- to 16-year-old children. Chronological age was found to account most strongly for differences in automated delta and REM count measures in this age range. Increasing age was shown to be associated with a significant decline in both automated measures, but the effect was much greater for the delta count measure. The age-related decline in delta wave activity was reflected primarily in a linear decline in 2.0-3.0 Hz delta activity, that is, in the faster end of the delta frequency band. Examination of these measurements in successive NREM and REM sleep periods confirmed that, in children as in adults, delta activity decreases and REM activity increases across the night. Findings are discussed relative to those obtained in the same children using standard measurement methods.