How to assess sympathetic nervous system activity in clinical practice.

The present paper reviews the techniques allowing to assess sympathetic activity in humans, highlighting their advantages and limitations. While plasma noradrenaline measurement represents a useful and widely used method to evaluate sympathetic neural function, new approaches, developed starting from the seventies, like direct recording of sympathetic nerve traffic and noradrenaline spillover. These approaches have largely supplanted the plasma noradrenaline approach due to the precise estimation of the behavior of regional sympathetic neural function. The paper in particular will focus the microneurographic technique, considered as the gold standard, and on the new clinical evidences obtained with this technique.