Implantable stimulating device for electrically or optically stimulating a vagus nerve (Vn), comprising, (a) a tissue coupling unit comprising one or more electrodes (40a, 40b) or optrodes configured for being implanted directly onto the vagus nerve (Vn) of a patient, (b) an EEG-unit comprising EEG-electrodes (70a-70d) and configured for measuring an electroencephalogram (EEG-) signal of the patient, (c) an encapsulation unit configured for being subcutaneously implanted in the patient body, and comprising a housing enclosing, ∘ an implanted pulse generator configured for emitting pulses of optical energy, ∘ an electronic circuit configured for sending a triggering signal to the IPG instructing the IPG to trigger energy pulses, (d) an energy transfer lead configured for transferring pulses of optical energy between the IPG and the tissue coupling unit, and comprising ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the tissue coupling unit, (e) a signal transfer lead configured for transferring signals between the EEG-unit and the electronic circuit, and comprising ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the EEG-unit, wherein the electronic circuit is configured for, • receiving EEG-conditioned data from the signal transfer lead, which is representative of the EEG signal measured by the EEG-unit, and • carrying out an analysis of the EEG-conditioned data yielding analysis results_and • taking a decision based on the analysis results and controlling the IPG according to the decision, wherein the decision includes instructing the IPG to send one or more energy pulses if the analysis results are representative of either a coming seizure, or an incipient or ongoing seizure. characterized in that, • the energy transfer lead includes one or more optical fibres, and in that • the signal transfer lead includes one or more optical fibres. (a) a tissue coupling unit comprising one or more electrodes (40a, 40b) or optrodes configured for being implanted directly onto the vagus nerve (Vn) of a patient, (b) an EEG-unit comprising EEG-electrodes (70a-70d) and configured for measuring an electroencephalogram (EEG-) signal of the patient, (c) an encapsulation unit configured for being subcutaneously implanted in the patient body, and comprising a housing enclosing, ∘ an implanted pulse generator configured for emitting pulses of optical energy, ∘ an electronic circuit configured for sending a triggering signal to the IPG instructing the IPG to trigger energy pulses, ∘ an implanted pulse generator configured for emitting pulses of optical energy, ∘ an electronic circuit configured for sending a triggering signal to the IPG instructing the IPG to trigger energy pulses, (d) an energy transfer lead configured for transferring pulses of optical energy between the IPG and the tissue coupling unit, and comprising ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the tissue coupling unit, ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the tissue coupling unit, (e) a signal transfer lead configured for transferring signals between the EEG-unit and the electronic circuit, and comprising ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the EEG-unit, ∘ a proximal end configured for coupling to the encapsulation unit and ∘ a distal end configured for coupling to the EEG-unit, • receiving EEG-conditioned data from the signal transfer lead, which is representative of the EEG signal measured by the EEG-unit, and • carrying out an analysis of the EEG-conditioned data yielding analysis results_and • taking a decision based on the analysis results and controlling the IPG according to the decision, wherein the decision includes instructing the IPG to send one or more energy pulses if the analysis results are representative of either a coming seizure, or an incipient or ongoing seizure. • the energy transfer lead includes one or more optical fibres, and in that • the signal transfer lead includes one or more optical fibres.