title: Motor laterality asymmetry and nonmotor symptoms in Parkinson's disease.
abstract: BACKGROUND
  In patients with Parkinson's disease (PD), asymmetric motor signs provide an interesting model to evaluate whether asymmetric nigrostriatal degeneration can affect neuropsychological function and other nonmotor symptoms (NMS). This study was designed to evaluate the predominant laterality of motor symptoms and its relationship with cognition and other NMS in idiopathic PD.
  
  
  METHODS
  Nationwide, longitudinal, and multicenter study (ELEP Registry) using outpatients with PD. Left PD (LPD) and right PD (RPD) was defined based on the motor signs on the SCOPA-motor scale. To include the clinical spectrum of asymmetric PD patients, we considered two groups of patients with mild-moderate and extreme asymmetry. Predominant LPD or RPD with mild-moderate versus extreme asymmetry were compared using the following scales: cognition, psychosis (Parkinson Psychosis Rating Scale), anxiety/depression, sleep (and autonomic dysfunction at baseline and 1 year later. Nonparametric tests were used for comparison.
  
  
  RESULTS
  One hundred forty-nine PD patients (74 RPD and 75 LPD) with mild-moderate asymmetry and 90 (47 RPD and 43 LPD) with extreme asymmetry and a mean age of 64.5 (10.4) years were included. Extreme RPD had higher Parkinson Psychosis Rating Scale scores over time (P = 0.005) compared with LPD, but no significant differences were observed between LPD and RPD in terms of other NMS.
  
  
  CONCLUSIONS
  These findings suggest that damage to left-hemisphere plays a disproportionately greater role in PD-related psychosis over time. In contrast, motor laterality does not consistently affect other NMS, suggesting that NMS are related to a more widespread brain disorder.
authors.affiliation: Neurology Department, Hospital General Yagüe, Burgos, Spain. esthercubo@gmail.com
authors.forename: Esther
authors.initials: E
authors.lastname: Cubo
authors.forename: Pablo Martinez
authors.initials: PM
authors.lastname: Martín
authors.forename: Jesus A
authors.initials: JA
authors.lastname: Martin-Gonzalez
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodríguez-Blázquez
authors.forename: Jaime
authors.initials: J
authors.lastname: Kulisevsky
mesh_terms: D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000209:etiology*; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D012720:Severity of Illness Index