title: Cognitive impairment in idiopathic Parkinson's disease.
abstract: BACKGROUND
  Cognitive symptoms are common in advanced Parkinson's disease (PD). However, assessment of cognitive impairment is difficult in PD because of accompanying motor symptoms and the coexistence of nonmotor symptoms. Specific subdomains affected in the disease are not reflected in the conventional scales used for assessing cognition.
  
  
  OBJECTIVE
  This study was aimed at looking at the spectrum of cognitive impairment in the various phenotypes and stages of PD and the correlation of cognitive impairment with motor and nonmotor symptoms of PD.
  
  
  METHODS
  Fifty PD patients fulfilling the UK PD Society Brain Bank's criteria were selected after obtaining explicit consent. Patients were assessed clinically and by using various scales like Scales for Outcomes in PD-Cognition (SCOPA-COG), mini-mental state examination, and Beck's Depression Inventory and Scoring.
  
  
  RESULTS
  The mean age was 58 years, 82% of the patients were male, and the mean modified Hoehn and Yahr staging was 2. The most commonly affected domains were memory and executive functioning. Cognitive impairment was more in those with late-onset disease, more advanced stage of disease, and in the postural instability and gait disorder (PIGD) subgroup. The cognitive function deteriorated with increasing age and duration of the illness. Significant correlation with cognitive impairment was obtained for the manifestations of increased motor disability, presence of coexistent psychotic symptoms and depression.
  
  
  CONCLUSIONS
  Cognitive impairment was common among PD patients, and it was more prevalent with increasing duration of the disease, in older patients, in late-onset disease, and in the PIGD subgroup. Increasing motor disability and associated psychotic symptoms as well as depression significantly increased the cognitive impairment.
authors.forename: Dhiman
authors.initials: D
authors.lastname: Das
authors.affiliation: Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India.
authors.forename: Atanu
authors.initials: A
authors.lastname: Biswas
authors.forename: Arijit
authors.initials: A
authors.lastname: Roy
authors.forename: Anna
authors.initials: A
authors.lastname: Sauerbier
authors.forename: Kalyan B
authors.initials: KB
authors.lastname: Bhattacharyya
mesh_terms: D060825:Cognitive Dysfunction / Q000209:etiology*; D003863:Depression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D011569:Psychiatric Status Rating Scales