A personal wearable EEG monitor comprising an implantable electrode part with at least two electrodes for measuring an EEG signal of a person. The electrode part comprises an electronic circuit arranged in a housing with each electrode arranged external to the housing. The electronic circuit is adapted for receiving an analogue EEG signal from the electrodes and is provided with an analogue to digital converter for converting the analogue EEG signal into a digital signal. The electrode part comprises a testing circuit for testing functionality of the electrode part. The testing circuit comprises a capacitor coupled in serial connection to at least one of the electrodes. The test circuit also comprises a test signal generator for providing a test signal, where the test signal generator is adapted for being coupled between the electrodes and the electronic circuit during a testing period, wherein said EEG monitor is adapted for analyzing the signal resulting from the signal generator for identification of faults in the electrode part.
