For children's sleep assessment: Can we trace the change of sleep depth based on ECG data measured at their respective home with a wearable device?

We tried to improve the sleep assessment method from the accelerations (ACC) and RR interval variations (RRIV) thar were measured with newly developed small and light-weight wearable ECG and ACC measuring devices (M-BIT). We performed the simultaneous measurement of M-BIT and polygraph, and verified the validity of our ACC-based sleep/awake identification method, and studied the relationships among parameters obtained through the time frequency analysis of M-BIT ECG RRIV, para-sympathetic (PSNS) and sympathetic nervous system's activity (SNS), coefficients of variation of RR intervals (CVRR), RRIV based respiration frequency (RFRE), its variation width in an epoch (VRFRE), heart rate (HR), and polygraph sleep stages.