| Abstract: | The continuous relative blood pressure measure obtained with a partially-inflated arm blood-pressure cuff operates under the same principle as the oscillometric method of blood pressure determination. In psychophysiological studies the rise in blood pressure seen, for example, in response to an emotion-evoking question, produces a rise in cuff pressure, along with any of three pulse-amplitude changes: a decrease, no change, or an increase. These seemingly paradoxical responses which accompany an increase in blood pressure may be explained by considering the relationship of cuff pressure to the cuff pressure for maximum oscillations. Experiments were conducted in which cuff pressure and its oscillations were recorded. Indications of an increase in blood pressure, and the pulse-amplitude changes resulting there from, were obtained at different cuff pressures in the same subject. The results confirm the hypothesis that with cuff pressure below the point of maximum oscillation, an increase in blood pressure results in a decrease in pulse amplitude. With a cuff pressure just above the point of maximum oscillations, an increase in blood pressure results in an increase in pulse amplitude. |
