Induction and assessment of experimental pain from human skin

Abstract

The ultimate goal of advanced human experimental pain research is to obtain a better understanding of mechanisms involved in pain transduction, transmission and perception under normal and pathophysiological conditions. Hopefully, this can provide better characterization, prevention and management of pain. As pain is a multi-dimensional perception it is obvious that the reaction to a single standardized stimulus of a given modality can only represent a very limited fraction of the entire pain experience. Evidently, the experimental possibilities available for studying cutaneous pain are much more advanced than the possibilities available for studying pain from deep tissue. Different techniques are available to induce repeated stimulation of skin and to assess the responses. Repeated stimulations can be used to assess centrall summation, which is a general and important mechanism for the human nervous system. Various stimulus modalities are available for induction of controlled experimental cutaneous pain, such as electrical (Trans-cutaneous, Intra-cutaneous), thermal (Heat, Cold), mechanical (Pin prick, Pressure, Impact stimuli) and chemical (Capsaicin, Mustard oil). The assessment methods for cutaneous pain are based on psychophysical, electrophysiological and imaging techniques. Experimental techniques can be used to study basic mechanisms in healthy volunteers or to characterize sensory dysfunction in patients. The experimental possibilities available for studying cutaneous pain are far from equal. There is a need for more experimental and clinical studies to provide new knowledge for this clinically revelant area.