Effects of vocalization on cardiovascular and electrodermal responses during mental arithmetic.

This study assessed the contribution of vocalization to autonomic responses during mental arithmetic. Specifically this study compared the autonomic responses of subjects during aloud and silent phases of repeated mental arithmetic tasks. The results were consistent for both tasks. As expected, heart rate and skin conductance responses were elevated during the aloud phases. Preejection period and cardiac output reactions, however, were greater during the silent phases. Furthermore, stroke volume declined during the aloud phases, but was maintained near resting levels during the silent phases. There were no phase effects for systolic pressure, diastolic pressure, or total peripheral resistance. The pattern of autonomic responses between aloud and silent phases of mental arithmetic suggest that the relationship between vocalization and autonomic response is not unidirectional but varies depending on the physiological parameter under investigation.