Neurological aspects of sleep medicine, how sleep evolves, and regulation of function

Sleep is not a static but rather is a dynamic state of being, involving variations in cerebral blood flow, neurotransmitters, immune response, and metabolic changes, among others. The maturation and development of the human brain involves changes across the life span, in particular changes from childhood to adulthood. The brain structure and function develop, neuronal networks strengthen, and neurotransmitter signaling is modulated in different ways affecting sleep and wakefulness. The most conspicuous changes in sleep architecture during infancy and early childhood include fundamental parameters studied in sleep medicine: decrease in total sleep time, gradual consolidation of periods of sleep at night or wakefulness during the day hours, decrease in the intensity of (EEG power) of NREM sleep stage 3 slow-wave activity (SWA), and a steady decline in the percentage of time spent in REM sleep. Furthermore, the control of sleep, including the two-process model (the circadian and homeostatic processes), also undergoes significant changes from childhood to adulthood. In this chapter we discuss these changes and processes especially important to help patients during the transition from childhood to adolescence and adulthood.