Epilepsy is one of the neurological disorders that manifests itself in epileptic seizures, which for the affected person assumes different neurobiological, cognitive, psychological and social consequences. It is necessary to diagnose this form of the disease in a timely and accurate manner, in order to be able to successfully treat patients. Electroencephalography (EEG), which is a non-invasive diagnostic method that measures and records electrical activities in the brain, greatly helps in this process. The objectives of this work include the identification of groups of patients according to the type of epileptic seizures in which specific EEG changes most often occur, the assessment of the frequency of specific EEG changes in patients with epilepsy (paroxysms, complex spike-wave, grouping tendency) between genders, the assessment of the frequency of specific EEG changes in patients with with epilepsy (paroxysms, spike-wave complex, grouping tendency) between age groups and comparison of the frequency of specific EEG changes (paroxysms, spike-wave complex, grouping tendency) during activation methods of hyperventilation and photostimulation. The medical documentation of the Karlovac General Hospital was used in the research, and included data on 164 patients in the period from January 1, 2023 to December 31, 2023. The results of the research showed that there is no significant connection between the types of epileptic seizures and the occurrence of specific EEG changes, there is no connection between the grouping tendency and gender, while the spike-wave complex was more often recorded in women. Also, the grouping tendency appears more often in patients aged 18 to 39 years, while spike-wave complex and paroxysms appear equally in all age groups, and specific EEG changes are equally recorded in the application of both activation methods, hyperventilation and photostimulation.