Waking ultradian rhythms of performance and motility in hyperkinetic and normal children.

Waking ultradian rhythms in a visual performance task (detections and false positives) and in motility (global body movements and segmental limb movements during the task, and segmental limb movements during off-task periods) were examined in groups of nonmedicated hyperkinetic (HK) children (N = 11) and matched normal controls (N = 11). Testing was conducted for 5 minutes every 15 minutes (with 10-minute "rest periods") over a 6-hour period on 2 consecutive days. Increased limb movement (p less than .01) during off-task periods on both days. Increased limb movement in HK subjects during the task was marginally significant (p less than .06) on one day. False positives and global body movements failed to differentiate the groups. With regard to ultradian rhythmicity, some subjects in both groups showed evident ultradian peaks, which were present across a wide range of frequencies in one or more variables. There were no significant differences in the incidence of the period of evident ultradian peaks between the two groups.