The newest version of the International Classification of Sleep Disorders (ICSD, 3rd. Ed.) uses State Dissociation as the paradigm for parasomnias. Unlike before, where wakefulness, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep were considered exclusive states, research has shown that combinations of these states are possible and thus, may result in unusual unstable states that could eventually manifest as parasomnias or as altered levels of awareness.Mahowald MW, Schenk CH. Dissociated states of wakefulness and sleep. In: Lydic R, Baghdoyan HA, editors. Handbook of behavioral state control: cellular and molecular mechanisms. Boca Raton: CRC Press; 1999. p. 143-58.Mahowald MW, Schenk CH. dissociated states of wakefulness and sleep. Neurology. 1992; 42(7 Suppl 6):44-51.
