Diagnosing autonomic nervous system disorders - existing guidelines and future perspectives

Primary and secondary autonomic nervous system (ANS) disorders often have a severe adverse effect on the quality of life of patients. Diagnostics for ANS disorders are under represented, despite their common occurrence. Precise history taking is of key importance for ANS evaluation: it may help to rule out differential diagnoses and provide important clues to the underlying ANS disorder. In fact, in conjunction with additional bedside tests, it can achieve a clear diagnosis. The analysis of heart rate variability and the results of the standardised tests that make up the Ewing battery are important means of evaluating the parasympathetic and sympathetic nervous system. In addition, sudomotor testing can be used to evaluate cholinergic sympathetic function, and the spontaneous baroreceptor reflex can be assessed using new computerised techniques. These tests provide valuable information on cardiovascular autonomic control. This paper presents a structured review of current standard techniques for diagnosing ANS disorders.