title: Relationship and factor structure in multisystem neurodegeneration in Parkinson's disease.
abstract: OBJECTIVE
  Parkinson's disease (PD) is a multisystem neurodegenerative disease. We aimed to identify the relationship and factor structure among its different features.
  
  
  METHODS
  Motor, olfactory and cognitive function, and cardiac sympathetic denervation were evaluated in 125 patients with PD using the Unified Parkinson's Disease Rating Scale (UPDRS) part III score, odor stick identification test for the Japanese (OSIT-J), Mini-Mental State Examination (MMSE), and [(123) I] meta-iodobenzylguanidine (MIBG) cardiac scintigraphy (heart-to-mediastinum (H/M) ratio). Pearson's correlation and multiple regression analysis were used to evaluate the association among the four measures with age, gender, and disease duration as the covariates. Exploratory factor analysis was used to identify the underlying factor structure among the measures and covariates.
  
  
  RESULTS
  Pearson's correlation and multiple regression analysis showed correlations between OSIT-J score and MIBG H/M ratio, OSIT-J and MMSE scores, UPDRS part III score and MIBG H/M ratio, UPDRS part III score and disease duration, and MMSE score and age. Factor analysis identified three factors: (i) age and MMSE score; (ii) MIBG H/M ratio and OSIT-J score; and (iii) UPDRS part III score and disease duration.
  
  
  CONCLUSIONS
  Our results suggest that aging, PD-related pathogenesis, and disease duration underlie the multisystem neurodegeneration present in PD. Moreover, age and disease duration are the major risk factors for cognitive impairment and motor symptoms, respectively. Olfactory impairment and cardiac sympathetic denervation are strongly associated in PD.
authors.affiliation: Department of Neurology and Neurological Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan; Department of Neurology, Kanto Central Hospital, Tokyo, Japan; Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: T
authors.initials: T
authors.lastname: Hattori
authors.forename: S
authors.initials: S
authors.lastname: Orimo
authors.forename: M
authors.initials: M
authors.lastname: Hallett
authors.forename: T
authors.initials: T
authors.lastname: Wu
authors.forename: A
authors.initials: A
authors.lastname: Inaba
authors.forename: R
authors.initials: R
authors.lastname: Azuma
authors.forename: H
authors.initials: H
authors.lastname: Mizusawa
mesh_terms: D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: Parkinson's disease; cardiac sympathetic degeneration; cognitive impairment; factor analysis; olfactory impairment; relationship