Galantamine improves cognition, behavioral symptoms and functioning: a 6-month non-interventional study by Fortos Andreas, Gatos Konstantinos, Varelas Georgios, Vagenas Vassileios, Sakka Paraskevi, Rigopoulou Stamatia, Papatriantafyllou Ioannis, Makris Nikolaos, Kontogianni Vassiliki, Fitsioris Xenofon, Politis Antonios, Tsolaki Magdalini, Oikonomidis Dimitrios, Giatas Konstantinos, Doskas Triantafyllos, Taskos Nikolaos, Mestoussi Angeliki, Vikelis Michalis