--to look for autonomic involvement, most (savvy) docs will start with the tilt table, to measure blood pressure reactions in different positions, have them perform the Valsalva test (bascially a test of seeing cardiovascular reactions to increased pressure), and then will do some form of sweat test, such as the sudomotor axon reflex test, in which small electrical cahrges are sent to the tiny nerves that control the sweat glands, and the response is measured:

http://peripheralneuropathycenter.uc...ic/qsart.shtml

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