Autonomic nerve function tests. Reference values in healthy subjects.

Autonomic nerve function was evaluated by deep breathing (E/I heart rate ratio) and tilt table tests (acceleration index, brake index, and blood pressures) in 56 healthy subjects in order to find reference values. The results showed that the E/I ratio, the acceleration index and the brake index fell with increasing age. There was no influence of age on the systolic and the diastolic blood pressure reactions to tilt. Age-related reference values are needed in the evaluation of autonomic neuropathy indices.