title: Side of onset does not influence cognition in newly diagnosed untreated Parkinson's disease patients.
abstract: BACKGROUND
  A relation between the side of motor onset and cognitive impairment in early PD has been reported, suggesting that the asymmetric degeneration affecting subcortical regions may play a pivotal role in lateralized cognitive function. However, evidences are controversial and all previous studies were performed on treated patients, though it is known that dopaminergic therapy can affect cognition in PD.
  
  
  METHODS
  Sixty-nine early untreated PD patients underwent an extensive neuropsychological battery exploring memory, visuospatial and attention/executive functions. Patients were divided with respect of the side of onset (right vs. left) and further grouped according to motor phenotype (tremor vs. rigidity-bradykinesia). Multivariate analysis of variance has been carried out to compare clinical and neuropsychological data between subgroups.
  
  
  RESULTS
  There were no differences in any neuropsychological task between right-sided and left-sided onset subgroups, irrespective of tremor dominant or rigid-bradykinetic phenotype. Age at onset was significantly higher in patients with any cognitive impairment as compared with patients without (66.7 ± 3.2 vs. 56.3 ± 6.8 years, p = 0.001).
  
  
  CONCLUSIONS
  Side of motor onset is not a major determinant for developing lateralized cognitive deficits in newly diagnosed untreated PD patients.
authors.affiliation: University Federico II, Naples, Department of Neurological Science, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Erro
authors.forename: Gabriella
authors.initials: G
authors.lastname: Santangelo
authors.forename: Marina
authors.initials: M
authors.lastname: Picillo
authors.forename: Carmine
authors.initials: C
authors.lastname: Vitale
authors.forename: Marianna
authors.initials: M
authors.lastname: Amboni
authors.forename: Katia
authors.initials: K
authors.lastname: Longo
authors.forename: Flavio
authors.initials: F
authors.lastname: Giordano
authors.forename: Marcello
authors.initials: M
authors.lastname: Moccia
authors.forename: Paolo
authors.initials: P
authors.lastname: Barone
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Pellecchia
mesh_terms: D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology* / Q000523:psychology