Single Pulse versus Pulse Train Cutaneous Electrical Stimulation during Cold Pressor Test

In the present study the effect of the cold pressor test (CPT) on the processing of electrical single pulses (SP) with changing amplitude and pulse trains (PT) with fixed amplitude was analysed using subjective pain ratings and evoked potentials. Healthy subjects were electrically stimulated at the left middle fingertip in a CPT and control protocol. In the CPT protocol the hand was immersed in water of 0-1°C; in the control protocol in water of 32°C. A total of 105 stimuli were applied in a protocol of five different stimulus amplitudes or number of pulses (NoP). The results showed a decrease of amplitude of EP wave components and decrease of subjective ratings by CPT, for both SP and PT. The relationship between NRS or EP amplitude and stimulus amplitude (SP) or NoP (PT) was unchanged by CPT.