Although the VU-AMS has been developed for impedance recordings in everyday, real world situations, it may also be used in laboratory settings, as several studies have already shown. The present paper will discuss these studies, with a special focus on the results of a recent study in our own laboratory.

In this study, hemodynamic and autonomic responses were measured in 48 participants during an 8.5 minute memory search task, an 8.5 minute cold pressor task and three rest periods. The data collected were used to examine the relative contribution of parasympathetic and sympathetic influences to subjects with low and high cardiac output responses. Stroke volume and heart rate (derived from impedance cardiography) were used to index the cardiac output response. The pre-ejection period (PEP) was used as an indicator of beta-adrenergic sympathetic activation, and heart rate variability (HRV) as an index of vagal tone.

Based upon their cardiac response, participants were divided into high cardiac responders and low cardiac responders. Preliminary results showed no significant differences between high and low cardiac responders, though high cardiac responders tended to show stronger decreases in PEP and HRV than low cardiac responders.

In addition to the results of this study, the requirements for and limitations of the use of the VU-AMS in laboratory settings will be discussed.

Paper presented at Measuring Behavior 2002 , 4^th International Conference on Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, The Netherlands

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