Protocols for Bedside Assessment of Autonomic Dysfunction in Parkinson's Disease and Multiple System Atrophy

Assessment of autonomic dysfunction is crucial for clinical management of PD and MSA. Autonomic dysfunction can provide important clues for its diagnosis and clinical management. Furthermore, it often progresses over time and significantly affects patients' quality of life. Therefore, it is essential to develop bedside clinical assessment protocols for autonomic dysfunction. This paper provides a step-by-step description to demonstrate the evaluation method. In both outpatient and bedside settings, autonomic function should be systematically evaluated: beginning with a medical interview, followed by a physical examination and, when necessary, using simple instrumental tests. Assessment should emphasize circulatory, sudomotor, urinary, and bowel dysfunction. This paper will explain each of the following items. Circulatory assessment: medical interview, evaluation of cold-discolored extremities, capillary refill, 10-second cold water stress load test, active standing test, the coefficient of variation of R-R intervals, and overnight oximetry provides further detailed evaluation in MSA. Sudomotor symptoms: medical interview, assessment of sweating at rest and under stress using palpation, visual inspection, and the spoon test, and finger wrinkling after immersion in warm water. Urinary assessment: urination frequency, sensation of incomplete bladder emptying, voiding diaries, and the measurement of post-void residual (PVR) urine volume. Bowel assessment: medical interview, abdominal percussion, and rectal ultrasonography. Bedside assessment is influenced by the examiner's experience, medication, and the testing environment. Considering the limitations of bedside assessments, more comprehensive diagnostic evaluations should be conducted when necessary. We also describe the characteristics of autonomic dysfunction in PD and MSA. Appropriate management of each type of autonomic dysfunction is also essential.