EEG correlates of a mental arithmetic task in patients with first episode schizophrenia and schizoaffective disorder. - Garakh Z; Zaytseva Y; Kapranova A; Fiala O; Horacek J; Shmukler A; Gurovich IY; Strelets VB (Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, 2015)