The aim of the study was to assess the influence of volatile induction of general anaesthesia with sevoflurane using two different techniques and intravenous anaesthesia with propofol on the possible presence of epileptiform electroencephalograph patterns during the induction of general anaesthesia. We aimed to verify whether presence of epileptiform patterns (EPs) defined as polispikes (PS), rhytmic polispikes (RPS), periodic epileptiform discharges (PED) on Electroencephalographs (EEGs) influence the behaviour of values of the Bispectral Index (BIS), State (SE) and Response (RE), A-line Auto Regressive Index (AAI) derived from middle latency auditory evoked potentials (MLAEP) during the induction of general anaesthesia using abovementioned techniques and such variations may be useful in detection of presence of EPs.