The reproducibility of cardiovascular reactions during cognitive tasks.

Psychophysiological applications have been proposed for and have been found in diagnostic procedures, in therapeutic processes as well as in therapy evaluation studies. Many studies in this area have been done on cardiovascular parameters like heart rate, blood pressure and peripheral resistance. Unfortunately there is still little evidence whether physiological reactivity in these test situations are reproducible. We investigated the stability of heart rate (HR) and pulse transit time (PTT) reactions during simple and complex cognitive tasks, in two sessions with some days in between. The data showed that with simple cognitive tasks the subjects showed a strong habituation on both measures within one session. This habituation did not take place with complex stressors. We also found significant lower reactivity in the second session. Heart rate showed significant test retest reliabilities for males and females with simple stressors and for females only with complex stressors. PTT never showed significant test retest reliabilities. So heart rate proved to be the more reliable indication for cardiovascular reactivity. However, it still seems premature to use psychophysiological paradigms in standard diagnostics.