Four Years Old Children's Sleep: What can we obtain by using wearable measuring devices at their home?

We have developed a sleep measuring system which can measure any subject at any pace. This system is consisted with wearable (size: 40×39×8mm, weight: 14g) acceleration and ECG measuring device and data analyzing software which able to output times in bed, sleep duration, NREM sleep proportion, sleep posture distribution and changing times, measures of autonomic system's activity, frequency of respiration and its variation, and results of sleep apnea detection. In this paper, we had measured 4 y.o. children and analyzed their sleep at home.