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Abstract

KATKIN, E. L. A comparison of the traditional polygraphic cardio measure with new techniques for continuous blood pressure assessment. January 1997, Report No. DoDPI97-R-0005. Department of Defense Polygraph Institute, Ft. McClellan, AL 36205-5114.

This project evaluated new technologies for the assessment of blood pressure responses in order to determine if they may contribute to increased reliability and validity of detection of deception. The traditional cardio measure was compared with two new devices (Finapres and Cortronic) designed to measure blood pressure accurately, unobtrusively, and continuously on each beat of the heart. Electrodermal measures were also taken. Two different experimental paradigms were used the orienting reaction and the "Stim" test, while continuous physiological measurement was taken on a traditional cardio measure, an electrodermal measure, and both the Finapres and the Cortronic automated blood pressure devices. Data from 28 female and 14 male subjects are reported. In the first experiment subjects were presented with 15 repeated 800-Hz tones at 70db, and their orienting reaction were recorded on all channels. In the second part of the experiment, subjects were given a Stim test in which they were to choose a card from a deck and then lie to the questioner about the card that was selected. Again, physiological measures were obtained continuously. The results indicated that the electrodermal measure showed the expected patterns of orienting reaction elicitation and habituation, but that none of the cardiovascular measure yielded any evidence of a systolic or diastolic blood pressure orienting response. Further, it was observed, as expected, that electrodermally labile subjects showed larger electrodermal orienting responses and a faster habituation rate than electrodermally stabile subjects. On the Stim test the electrodermal measures significantly discriminated between lies and truth (p <.01), although there was no effect of lability. This suggests that although electrodermal lability affects orienting responses it does not affect the discrimination of deceptive from truthful responses. There were no significant findings for any of the blood pressure measure on the Stim test.

Key words: blood pressure, electrodermal response, orienting response, stim test, automated blood pressure assessment, finapres, cortronic, detection of deception.