[Measuring psychophysiologic variables during conversations. Quantifying pulse volume changes].

Little is known about connections between events in verbal communication and related physiological variables. Usually used procedures in quantification of pulsevolume data are based on simplifications neglecting essential characteristics of the curve between heart beats. It is shown that the concept of interbeat-intervals (IBI) underlying conventional methods hides these characteristics putting up with a delay in time between heart beats and related verbal factors. An alternative procedure of the extraction of period and amplitude is demonstrated. A software-package is developed to transform and interactively control the analysis of the pulsevolumesignal (filtering and vector-transformation). As results quasi-continuous time series of period and amplitude of the pulsecurve are shown, tracing the shape of the curve in each cardiac cycle. Some first applications of the method in stress research are discussed. The method is appropriate especially for detecting "short time" changes of cardiac activity in naturalistic observational settings (e.g. dyadic interaction).