“…The premonitory phase has been studied in some detail in the literature over the years, in both adults and children, with a variety of study designs and patient populations ( Blau, 1980 ; Drummond and Lance, 1984 ; Waelkens, 1985 ; Rasmussen and Olesen, 1992 ; Russell et al, 1996 ; Giffin et al, 2003 ; Kelman, 2004 ; Quintela et al, 2006 ; Schoonman et al, 2006 ; Cuvellier et al, 2009 ; Guo et al, 2016 ; Karsan et al, 2016 , 2020b ; Laurell et al, 2016 ; Jacobs and Pakalnis, 2019 ; Onderwater et al, 2020 ; Wang et al, 2021 ). While some studies have looked at prevalence and the ability of these symptoms to predict impending headache, others have focused on phenotype.…”