Table 4.

Investigations of autonomic dysfunction

Assessment of global autonomic function

A. Tests of thermoregulatory function

B. Tests of exocrine and pupillary regulation

C. Tests of gastrointestinal autonomic regulation

D. Tests of genitourinary autonomic regulation

Specific tests for cardiac and vascular autonomic regulation

A. Evaluation of cardiac vagal innervation

1. Heart rate response to deep breathing

2. Heart rate response to Valsalva maneuver

3. Heart rate response to postural change (the 30:15 ratio)

B. Evaluation of cardiovascular sympathetic innervation

1. Cardiovascular response to postural change

2. BP response to Valsalva maneuver

3. Cold pressor test

4. BP response to sustained handgrip maneuver

Specific tests to differentiate preganglionic from postganglionic disorders

1. Supine plasma catechols

2. Neuropharmacologic probes

3. Cardiac sympathetic neuroimaging

Abbreviation: BP, blood pressure.