Testing of Autonomic Function

Abstract

Autonomic testing is important in the diagnosis of small-fiber involvement in the diagnosis of a neuropathy and evaluation of syncope and orthostatic intolerance. These studies are also useful in assessing disorders with suspected central autonomic dysfunction such as multiple system atrophy or Lewy body disease. Autonomic studies are often helpful in identifying dysautonomia in patients with impotence, constipation, or incontinence and in painful disorders as seen in the complex regional pain syndrome. This chapter covers autonomic studies in details including cardiac responses to Valsalva maneuver and deep breathing, sudomotor studies, tilt table testing, skin blood flow assessment, and pupillometry.