[Neurovegetative function tests: clinical importance and physiological aspects]

Abstract

Evaluation of autonomic defects in polyneuropathies or diseases of the central nervous system is assuming increasing importance. Five simple non-invasive cardiovascular tests are described: an orthostatic test taking account of changes in arterial blood pressure, the orthostatic test of Ewing, the Valsalva maneuver, sustained handgrip, and heart beat to beat variation. The physiological mechanisms involved in each test, the need to bear in mind failure of the effector organs (cardiovascular system) and also the effect of medication are discussed. Finally, the beat to beat variation expressed as the coefficient of variation and as the meansquare successive difference, measured in 32 healthy subjects, are suggested as reference values.