[Experimental pain-induction methods in the systematic study of human pain: quality criteria.]

The aim of this investigation has been to test in humans the reliability and validity of three painful stimuli, i.e, mechanical pressure, a modified submaximum-effort tourniquet technique, and the cold pressure test. Twenty-four untrained subjects (twelve females, twelve males) volunteered in the experiments and, after a trial session were presented with four runs of these three noxious stimuli within 36 h. They assessed the painfulness using a direct scaling technique (category subdividing procedure). It was shown that all pain-induction methods gave reliable results (Cronbach's alpha>-0.90). Significant intercorrelations between the results of the application of mechanical pressure and ischemia support the validity of these two stimuli. Stimulation by cold, on the other hand, did not reveal such coherence. Repeated mechanical stimulation caused sensitization that did not occur with ischemia or cold. There were no significant differences whether the experiments were performed in the morning or in the evening. Experimental pain induction either by mechanical pressure or by ischemia judged in accordance with the category subdividing procedure produce reliable and valid results; the methods are easily applicable and economic.