Influence of transcutaneous nerve stimulation (TNS) on acute pain.

Using transcutaneous nerve stimulation (TNS) simple surgical procedures such as tooth extractions and nerve biopsies can be performed without the usual anesthetics. Estimation of threshold and suprathreshold intensities of painful electrical stimuli show no significant change during TNS. Only the threshold for non-painful electrical stimuli is slightly increased. Cortical potentials evoked by electrical peripheral nerve stimulation are not significantly modulated by TNS. Latencies of the early components 0, I--III are unchanged, the amplitudes only slightly reduced. These observations are in contradiction to the 'gate-control' theory of pain.