Analysis of EKG for fetus affected by mother's heartbeat signal

Cognitive functions can be detected by heartbeat signals. We have obtained EKG data from neonates in three cognitive states - rest, auditory stimulus and (post) rest states. We have got several statistical properties of the heartbeat signals from the neonates who were used to hear artificial heartbeat signals when they were in their mother's womb. Also, we compared them with those of normal neonates who were not. Auditory stimulus used in this experiment mimics mother's heartbeat signal. All the neonates tested were about 5 months old. There is no significant difference in mean-heart rates and standard deviation of heart rate between two groups and among three states. However the statistical characteristics based on nonlinear dynamics and information theory, which tells the difference between two groups and among three states has been detected.