AAEM minimonograph #48: autonomic nervous system testing

Area of Science:

• Clinical neurophysiology
• Autonomic nervous system function

Background:

• The autonomic nervous system regulates vital functions like cardiovascular, thermoregulatory, and pupillary responses to maintain homeostasis.
• Accurate testing of autonomic nervous system function is challenging but essential in clinical neurophysiology.

Purpose of the Study:

• To review and outline the various methods for testing and quantifying autonomic nervous system function.
• To highlight the importance of using a battery of tests for improved sensitivity and reliability.

Main Methods:

• Parasympathetic cardiovagal function is assessed via heart rate variability during standing, deep breathing, and the Valsalva maneuver.
• Sympathetic adrenergic vascular regulation is evaluated using blood pressure responses to standing, Valsalva maneuver, handgrip, mental stress, and cold immersion.
• Sympathetic cholinergic sudomotor function is tested through sympathetic skin response, quantitative sudomotor axon reflex testing, and sweat analysis.
• Pupil function is assessed using pharmacological and pupillographic techniques.

Main Results:

• Available autonomic function tests vary in sensitivity and ease of administration.
• Gastrointestinal and genitourinary function tests are less effective at isolating autonomic regulation.
• Administering tests in a battery enhances overall sensitivity and reliability.

Conclusions:

• A comprehensive battery of autonomic function tests is necessary for accurate assessment.
• These tests aid in probing diverse autonomic functions, improving diagnostic capabilities.