AN EVALUATION OF TWO METHODS OF ALGESIMETRY IN HUMAN SUBJECTS Academic Article uri icon

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abstract

  • The effect of analgesic drugs and placebos on experimental pain thresholds has been studied in 60 untrained and three trained human subjects. Muscle compression (cuff method) and compression of tissues overlying bone (aesthesiometer method) have been employed as pain-producing stimuli. The two methods manifest a comparable degree of reproducibility. The following coefficients of variation were obtained: (1) subject-to-subject, 80%; (2) day-today, 20%; (3) moment-to-moment, 10%.The threshold elevations produced by analgesics were small and, in most cases, not significantly greater than those obtained with placebos. Responses to various agents with each method of measurement tended to be consistent from one time interval to the next on a given test occasion. There also was a positive correlation between the simultaneous results as measured by the two different procedures in the case of agents producing significant threshold elevations. However, there was no correlation between the responses of the subjects to placebos and to analgesic agents. The majority of subjects were inconsistent in their reactions to placebos. Neither exclusion of placebo reactors nor training of subjects enhanced the accuracy of threshold reproducibility or the ability to discriminate between agents. Neither method of measurement revealed threshold changes to analgesics which were large enough to detect practical differences in the potency of various agents or in the effects of different doses of the same agent.

publication date

  • July 1, 1957