For obtaining a sequence of mutually comparable measurement results, it is desirable to position a number of electrodes on a patient body (10) at substantially the same position for each measurement. As such measurements may be performed every day, it is desirable for a patient to be able to perform the measurement at home, for example. The present invention provides a method and system (100) for enabling a not medically trained person to position the electrodes at substantially the same position for each measurement. The method comprises capturing an image (126) of the patient (10) and comparing the image (126) with a reference image (128). In the reference image (128), the electrode positions (130) are indicated. The electrode positions (130) of the reference image (128) are superimposed on the image (126) of the patient (10). An indicator system (134) indicates the position (130) of the electrodes such that the patient (10) may position the electrodes correctly.