Sleep states and behavior patterns in preterm and fullterm infants.

The sleep states and state-related behaviors of 10 preterm infants were naturalistically observed at 37 and 41 weeks CA; 20 fullterm infants were also observed at 41 weeks CA. Respiration was recorded in synchrony with the behavioral observations. At 41 weeks CA the preterm infants seemed more mature than the fullterm infants on some measures, and less mature on others. These results indicate global differences in state organization, although neither the causes nor the consequences of these differences are currently known.