Utility and best practices for clinical diagnostic testing of the autonomic nervous system: A Consensus Statement Endorsed by the American Autonomic Society and the American Association of Neuromuscular & Electrodiagnostic Medicine

PURPOSE: Disorders of the autonomic nervous system are prevalent and associated with substantial morbidity, mortality and diagnostic delay. Standardized, laboratory-based autonomic function testing provides objective physiological data essential for diagnosing, staging, and monitoring autonomic disorders, yet no current consensus statement establishes best practices for the conduct, interpretation, and minimum quality standards of such testing. METHODS: The American Autonomic Society convened a writing committee of autonomic specialists to review published evidence and established practices governing standardized autonomic reflex function testing in clinical settings. This consensus statement builds upon prior position statements published by North American and European professional societies. RESULTS: We summarize the clinical evidence supporting standardized autonomic reflex function testing across a broad range of conditions, including neurodegenerative disorders, peripheral neuropathies, orthostatic intolerance syndromes, and autoimmune autonomic disorders. We describe the validated battery of tests -orthostatic challenge, Valsalva maneuver, cardiovagal heart rate variability testing, and sudomotor testing-with attention to physiological principles, technical standards, and clinical interpretation. Minimum standards are defined for the requisite roles in autonomic testing: the autonomic technician, supervising clinician, and interpreting autonomic physician. Special considerations for pediatric, pregnant, and critically ill populations are addressed, and emerging adjunctive techniques are reviewed. CONCLUSION: Standardized autonomic reflex function testing is clinically useful, well validated, evidence-based, and non-investigational when performed by qualified personnel adhering to best practices. Autonomic testing is irreplaceable for clinical decision-making in certain circumstances and should be integrated into clinical practice when appropriate.