Covariation and Temporal Stability of Peripheral and Brachial Blood Pressure Responses to Mental and Static Stress

Abstract Peripheral blood pressure measurement (Finapres technique) is a promising development in activation research. This paper tests and compares the temporal stability and covariation of peripheral and brachial blood pressure responses. Forty healthy subjects were tested four times at intervals of 1 day, 1 week, and 1 month. The tasks employed were two mental tasks (mental arithmetic and a Color Word Test) and a static (fingergrip) task. Recorded physiological parameters were peripheral and brachial systolic (SBP) and diastolic blood pressure (DBP). Mean peripheral SBP was about 20 mmHg higher than brachial SBP, but the difference between the DBP measures was negligible. Correlations between peripheral and corresponding brachial BP resting levels were low, with coefficients below 0.30. The correlations between peripheral and brachial SBP and DBP were higher for reactivity (change) scores (0.46-0.82) than for resting scores. Several types of inter- and intraindividual covariation were calculated to provide a deeper understanding of the relationship between the physiological parameters with respect to their dynamics. Temporal stability of peripheral BP level scores was lower (0.37-0.57) than for brachial BP (0.59-0.77), but the stability of the change scores was similar for both BP techniques. The results show that it is important to distinguish between several aspects of the mutual relationship between peripheral and brachial BP measures. Peripheral BP measurements are not suited to assess the BP level of a subject, but they are very useful to assess cardiovascular reactivity.