title: The role of autonomic testing in the differentiation of Parkinson's disease from multiple system atrophy.
abstract: Differentiation of idiopathic Parkinson's disease (PD) from multiple system atrophy (MSA) can be difficult. Methods devised to help distinguish the two disorders include standardized autonomic testing and cardiac imaging with iodine-123 meta-iodobenzylguanidine myocardial scintigraphy. MSA patients had more severe adrenergic and overall autonomic dysfunction when compared to control and PD patients. Area of anhidrosis on thermoregulatory sweat test was greater in MSA (67.4±12.42, p<0.001) versus PD patients (area of anhidrosis, 1.7±2.96). Postganglionic cardiac sympathetic innervation (iodine-123 meta-iodobenzylguanidine) expressed as heart to mediastinal ratio was significantly lower in Parkinson's disease patients (1.4±0.40, p=0.025) compared to controls (2.0±0.29), but not in multiple system atrophy (2.0±0.76). These findings indicate that autonomic dysfunction is generalized and predominantly preganglionic in multiple system atrophy, and postganglionic in Parkinson's disease. In our hands the thermoregulatory sweat test provides the best distinction between MSA and PD. However further confirmatory studies using larger patient numbers are required. Currently a combination of clinical judgment and autonomic testing is recommended to help differentiate MSA and PD.
authors.affiliation: Department of Clinical Neurological Sciences, London Health Sciences Centre, University of Western Ontario, London, ON, Canada.
authors.forename: Kurt
authors.initials: K
authors.lastname: Kimpinski
authors.forename: Valeria
authors.initials: V
authors.lastname: Iodice
authors.forename: Duane D
authors.initials: DD
authors.lastname: Burton
authors.forename: Michael
authors.initials: M
authors.lastname: Camilleri
authors.forename: Brian P
authors.initials: BP
authors.lastname: Mullan
authors.forename: Axel
authors.initials: A
authors.lastname: Lipp
authors.forename: Paola
authors.initials: P
authors.lastname: Sandroni
authors.forename: Tonette L
authors.initials: TL
authors.lastname: Gehrking
authors.forename: David M
authors.initials: DM
authors.lastname: Sletten
authors.forename: J E
authors.initials: JE
authors.lastname: Ahlskog
authors.forename: Robert D
authors.initials: RD
authors.lastname: Fealey
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Singer
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Low
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology; D001833:Body Temperature Regulation / Q000502:physiology*; D003943:Diagnostic Techniques, Neurological / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis* / Q000503:physiopathology*; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology*; D011446:Prospective Studies; D012018:Reflex / Q000502:physiology*; D013546:Sweating / Q000502:physiology