Table 1.

Observations of autonomic electrophysiology in Parkinson’s Disease

Organ system	Condition/Maneuver	Results in PD relative to controls	Interpretation
Cardiovascular system	Valsalva	Lower compensatory increase in SBP[17]	Sympathetic deficiency in baroreflex
	Premature Ventricular Contractions	Lower compensatory increase in SBP[67]	Sympathetic deficiency in baroreflex
	Respiratory Sinus Arrythmia (measured during Valsalva, deep breathing, standing up or hand grip)	Lower hear rate variability[19, 20]	Parasympathetic deficiency in vagal influence
Skin/sweat gland	Sympathetic skin response	Lower amplitude and longer latency[21, 25– 28, 30, 68, 69]	Sympathetic deficiency in distal extremities
	Thermoregulatory Sweat test	10–40% anhidrosis[32–34]	Cutaneous sympathetic deficiency
	QSART	Normal or lower sweat response[35, 36]	Post-ganglionic cutaneous sympathetic deficiency
	Microneurography	Lower skin sympathetic peroneal nerve activity[37]	Post-ganglionic cutaneous sympathetic deficiency
Urinary Tract	Urodynamic testing	Reduced bladder capacity, detrusor overactivity, external sphincter relaxation[38]	Parasympathetic dysfunction in nigrostriatal and ventral-tegmental-mesolimbic systems
Gastrointestinal Tract	Colonic scintigraphy	Longer colonic transit time[44]	Parasympathetic dysfunction in enteric network and vagus
	Esophageal manometry and scintigraphy	Esophageal dysmotolity[41]	Parasympathetic dysfunction in vagus motor pathways
	Gastric scintigraphy	Delayed gastric emptying time[70]	Parasympathetic dysfunction in vagus motor pathways
	Electrogastrography	More time with gastric dysrhythmia[47]	Relatively lower gastric parasympathetic tone
Pupillary System	Light reflex pupillography	Lower constriction velocity[50]	Lower parasympathetic function from the Edinger-Westphal nucleus

SBP=systolic blood pressure; QSART=quantitative sudomotor axon reflex test;