Electroencephalography power spectra and electroencephalography functional connectivity in sleep

This chapter introduces quantitative electroencephalographic (QEEG) literature about normal and pathological sleep. It starts by introducing QEEG methods with a particular focus about power spectrum, functional connectivity analyses (i.e., coherence and phase synchronization), and source localization methods. It then illustrates the QEEG literature, from a power spectrum and a functional connectivity point of view, both about normal sleep process and pathological sleep conditions such as primary insomnia, sleep-related breathing disorders (e.g., obstructive sleep apnea syndrome), sleep parasomnias, and those occurring in neuropsychiatric and neurodegenerative diseases. Finally, the chapter provides a discussion about the clinical implications and future directions about sleep-related QEEG research.