Relationship between amount of sleep and daytime sleepiness in three cases.

The effect of sleep amount on daytime sleepiness was investigated, and the appropriate amount of sleep for each subject was evaluated. Three children were longitudinally evaluated for three conditions: control, sleep extension, and sleep reduction. A sleep latency test was conducted five times for each condition at 2-h intervals from 10.00 hours. The results showed that the effects of sleep loss increased sleepiness at 10.00 hours and 18.00 hours, and there were positive correlations between sleep amount and sleep latency for each subject (r = 0.590-0.903). Whether or not the amount of sleep for each subject was sufficient was evaluated from the relationship between the two measures.