“…In response to these challenges, many automatic sleep staging methods using statistical learning or artificial intelligence techniques have been developed (Park et al, 2000, Agarwal and Gotman, 2001, Caffarel et al, 2006, Porée et al, 2006, Tagluk et al, 2010and Pan et al, 2012. The complexity of the sleep staging problems can be furthered alleviated by extracting features from fewer signal channels (Agarwal et al, 2005, Berthomier et al, 2007, Virkkala et al, 2007a, Virkkala et al, 2007b, Malinowska et al, 2009, Güneşa et al, 2010, Levendowski et al, 2012and Stepnowsky et al, 2013.…”