ABSTRACT
Recent advances in computer technology have made it possible to noninvasively determine fast and dynamic changes in autonomic nervous activity in humans. Power spectral analysis of heart rate variation, beat-to-beat blood pressure analysis, skin blood flow by the laser Doppler technique, sensitive sudorometry and direct measurement of sympathetic nervous discharge have been successfully applied in adults, but there are still only few studies reported in children and adolescents. This article reviews the usefulness of these autonomic function tests in the pediatric field including reliability and methodological limits. Power spectral analysis of heart rate variability seems to be a new potential method, but there have been only few studies in children. Orthostatic maneuvers with noninvasive beat-to-beat measurement of finger arterial pressure, especially during active standing, is useful for the evaluation of orthostatic intolerance in children as well as adults with autonomic failure. A new pharmacological method using multiple autonomic agents might indicate a more precise information including alpha- and beta-adrenoceptor sensitivity. It should be realized that a single test cannot identify impaired autonomic functions, and a combination of several autonomic tests should be employed. Moreover, age-related changes and racial differences in autonomic function should be considered when interpreting obtained results