Embodiments of the invention relate to a wireless physiological monitoring system. The system includes at least one wireless sensor and a monitoring device which are linked to one another of a wireless fashion for measuring physiological signals of a patient. The at least one wireless sensor is located on the patient and may comprise a wireless surface electrode assembly or a wireless needle assembly. The system may also comprise a wireless stimulator synchronized with the wireless sensor for performing certain diagnostic tests, such as nerve conduction velocity tests, for example. The wireless sensor preferably includes active, reference and common conductors. The common conductor can be used to measure the common mode voltage of the patient in the vicinity of the testing, and this voltage can then be subtracted from the measured active and reference voltages.