Vaclava VP Piorecka

Abstract The electroencephalogram (EEG) reflecting brain activity may be characterised through brief periods of stable neural activity patterns that recur over time and are referred to as microstates. Microstates are related to a range of cognitive processes, and their analysis has become an increasingly popular tool for studying human brain function.

1 INTRODUCTION Insomnia is the second most common mental disorder in Europe (Wittchen et al., 2011) affecting ~10% of the population (Ohayon, 2002). Insomnia is a disabling condition increasing the risk of cognitive impairments, mood disturbances, and the development of mental disorders, such as depression (Baglioni et al., 2011).

Abstract The pathophysiology of recurrent isolated sleep paralysis (RISP) has yet to be fully clarified. Very little research has been performed on electroencephalographic (EEG) signatures outside RISP episodes. This study aimed to investigate whether sleep is disturbed even without the occurrence of a RISP episode and in a stage different than conventional REM sleep. 17 RISP patients and 17 control subjects underwent two consecutive full-night video-polysomnography recordings.