Abstract: The present disclosure describes an electrode patch, and a method, a measurement arrangement, and a detection system utilizing the electrode patch for detecting an indicator of Parkinson's disease in a person from a muscle in a limb of the person. The electrode patch comprises two measurement electrodes, wherein a distance between centres of the measurement electrodes is above 2 cm and less than 4 cm, and a reference electrode positioned such that a lateral distance of from a centre of the reference electrode from to an axis passing through the centres of the measurement electrodes is at least he distance between the measurement electrodes.