Description

The tests most widely applied to assess the integrity of the autonomic nervous system are those described by Ewing & Clarke.

There are 5 tests, the first 3 tests reflect parasympathetic function, while the other 2 correlate with sympathetic function.

The tests, based on cardiovascular reflexes, are simple and non-invasive and have been shown to provide a broad assessment of autonomic function.

They do not detect vasodepressor responses or cardio-inhibitor responses for which a 70 degree head up Tilt Table test is required. They will also not detect syncope related to carotid sinus hypersensitivity for which carotid sinus massage is needed.

The following equipment is required: A Sphygomanometer, an electrocardiograph; an Anaeroid manometer; a handgrip dynamometer and a couch and chair.

For the tests to be valid, there should be no significant cardiac failure or arrythmia. The tests require the subject to understand and comply with fairly complex instructions and be able to stand from the supine position with minimal assistance.