A matrix electrode configuration for carrying out electrode measurements on the surface of the skin of a patient's head for recording the electrical activity of the brain, the matrix electrode configuration comprising - a body part of non-conductive material conforming to the contours of the surface of the skin, - electrodes connected to said body part for producing measurement data, wherein the body part has an electrode placement configuration for maintaining mutual placements of the electrodes essentially the same with respect to one another, - transmission lines connected to said body part for transmitting the measurement data to be received to a measurement data unit during use in order to further process the measurement data, and - an active attachment surface configured to be located between the electrodes and the surface of the skin, said active attachment surface comprising hydrogel or other electroconductive adhesive material which adheres well to the skin in order to form a stable and essentially interference-free attachment contact between the electrodes and the skin surface, characterized in that - the electrodes and the transmission lines are made of conducting wires forming a conducting layer on a surface of a first side of the body part, wherein the conducting wires forming the electrodes define spiral shapes for the electrodes, and wherein the electrodes are suitable to be in contact with hairless skin area through the electroconductive active attachment layer, - the matrix electrode configuration comprises an insulator coating layer on the body part covering the conducting layer to avoid short-circuiting of the wires, wherein the insulator coating layer is provided with openings at the electrodes, and - the matrix electrode configuration comprises a grounding layer formed completely or partly over the body part on a second side, opposite to the first side, of the body part to prevent the effect of external electrical interferences, the grounding layer being isolated from the active attachment surface and the conducting layer by the body part and/or by an additional isolation layer. - a body part of non-conductive material conforming to the contours of the surface of the skin, - electrodes connected to said body part for producing measurement data, wherein the body part has an electrode placement configuration for maintaining mutual placements of the electrodes essentially the same with respect to one another, - transmission lines connected to said body part for transmitting the measurement data to be received to a measurement data unit during use in order to further process the measurement data, and - an active attachment surface configured to be located between the electrodes and the surface of the skin, said active attachment surface comprising hydrogel or other electroconductive adhesive material which adheres well to the skin in order to form a stable and essentially interference-free attachment contact between the electrodes and the skin surface, characterized in that - the electrodes and the transmission lines are made of conducting wires forming a conducting layer on a surface of a first side of the body part, wherein the conducting wires forming the electrodes define spiral shapes for the electrodes, and wherein the electrodes are suitable to be in contact with hairless skin area through the electroconductive active attachment layer, - the matrix electrode configuration comprises an insulator coating layer on the body part covering the conducting layer to avoid short-circuiting of the wires, wherein the insulator coating layer is provided with openings at the electrodes, and - the matrix electrode configuration comprises a grounding layer formed completely or partly over the body part on a second side, opposite to the first side, of the body part to prevent the effect of external electrical interferences, the grounding layer being isolated from the active attachment surface and the conducting layer by the body part and/or by an additional isolation layer.