Autonomic Nerve Function Tests in Patients with Diabetes

Abstract

The autonomic nervous system (ANS) regulates the internal functions of the body organs, such as heart rate, digestion, respiratory rate, pupil response, urination, and sexual arousal. The ANS is divided into two parts: the sympathetic and parasympathetic nervous systems. However, the ANS can be damaged or degenerated by metabolic problems including hyperglycemia, leading to diabetic autonomic neuropathy (DAN), which is a prevalent complication among diabetic patients. Cardiac autonomic neuropathy is an important form of DAN that results from an imbalance between the sympathetic and parasympathetic nerve responses. This imbalance can lead to symptoms such as resting tachycardia, postural hypotension, and orthostatic tachycardia along with other types of autonomic neuropathy. Special tests can be performed to evaluate and diagnose this condition, including cardiovascular autonomic function tests. The aim of this review is to discuss the various tests used to diagnose and monitor autonomic neuropathy in diabetic patients and how to use and interpret them effectively.