The present invention relates to a device for pre-seizure warning of hypoglycaemic attacks, which is a big problem for especially diabetics, who are in insulin treatment. The device is configured to collect the EEG signal from two or more subcutaneous or intracranial electrodes (10) and by signal analysis identify pre-seizure characteristic changes in the EEG signal comprising a decrease in frequency content and an increase in amplitude and give a warning signal after identification of the characteristic EEG changes. The device comprises a signal processing unit (12) for receiving said EEG signals and for performing said analysis, and an alarm signal giver, both of which may be placed subcutaneously. When the pre-seizure characteristics signal changes are detected, a warning signal is given to the person by means of the alarm giver, e.g. in form of a vibrator. The device may be configured to transmit the EEG signals from the subcutaneously placed electrodes to the subcutaneously placed signal processing unit via subcutaneously drawn wires (11).
