Author information:
(1)Neuroscience Section, Department of Applied Clinical Sciences and 
Biotechnology, University of L'Aquila, via Vetoio, 67100, L'Aquila, Italy. 
simona.sacco@univaq.it.
(2)Department of Neurology, Danish Headache Center, Rigshospitalet Glostrup, 
Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 
Denmark.
(3)Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany.
(4)Department of Neurology, Leiden University Medical Center, Leiden, The 
Netherlands.
(5)1st Department of Neurology, National and Kapodistrian University of Athens, 
Athens, Greece.
(6)Department of Clinical and Molecular Medicine, Sapienza University, Rome, 
Italy.