2025 Workshop Handout Bundle-W02TA Autonomic Testing

W02TA Autonomic Testing - Peltier

Pdf Summary

This document by Dr. Amanda Peltier and Dr. Phillip A. Low provides an overview of laboratory evaluation of autonomic function, emphasizing non-invasive, quantitative testing aligned with Current Procedural Terminology (CPT) codes. Autonomic testing complements neurological history and examination and focuses on detecting, quantifying, and determining the distribution and site of autonomic failure.<br /><br />Indications for autonomic evaluation include suspected generalized autonomic failure conditions such as multiple system atrophy (MSA), pure autonomic failure (PAF), and autonomic neuropathies (e.g., diabetic, amyloid, Sjogren’s syndrome, sub-acute autoimmune). Testing also helps diagnose limited autonomic failure presenting as syncope, distal small fiber neuropathy, postural tachycardia syndrome (POTS), and distinguish benign from life-threatening autonomic disorders.<br /><br />Routine autonomic tests include:<br />1. Quantitative Sudomotor Axon Reflex Test (QSART) – measures postganglionic sympathetic sudomotor function via acetylcholine-induced sweat response. QSART is reproducible, quantitative, and indicates distal axon integrity. Normal values accounting for age and gender are provided.<br />2. Heart Rate response to Deep Breathing (HRDB) – assesses cardiovagal function with normative data demonstrating age effects.<br />3. Valsalva ratio (VR) – evaluates cardiovagal and adrenergic function by monitoring heart rate and beat-to-beat blood pressure (BP) during standardized Valsalva maneuvers (40 mm Hg pressure for 15 seconds).<br />4. Beat-to-beat BP and HR responses during Valsalva and Head-up Tilt – assess adrenergic function, distinguishing stages of BP response phases and detecting orthostatic hypotension.<br /><br />The document outlines patient preparation, factors influencing test results, and standard recording sites. It stresses the importance of comprehensive testing sequence (QSART, then HRDB, Valsalva, and tilt) and includes a Composite Autonomic Scoring Scale (CASS) for grading autonomic failure severity, validated across patient groups.<br /><br />Finally, guidance on autonomic laboratory equipment needs—tilt table, beat-to-beat BP device, continuous heart rate monitoring, and sudomotor recording—is provided, along with extensive references for further study. Overall, this workshop handout serves as a practical and theoretical guide for clinical autonomic evaluations.

Keywords

autonomic function testing

Quantitative Sudomotor Axon Reflex Test

heart rate deep breathing

Valsalva maneuver

beat-to-beat blood pressure

postural tachycardia syndrome

multiple system atrophy

autonomic neuropathies

Composite Autonomic Scoring Scale

clinical autonomic evaluation