title: The Addenbrooke's Cognitive Examination for the differential diagnosis and longitudinal assessment of patients with parkinsonian disorders.
abstract: OBJECTIVE
  Differentiating idiopathic Parkinson's disease from atypical parkinsonian syndromes is challenging, especially in the early stages. We assessed whether the Revised Addenbrooke's Cognitive Examination (ACE-R) could differentiate between parkinsonian syndromes and reflect longitudinal changes in cognition in these disorders.
  
  
  METHODS
  The ACE-R was administered at baseline and after approximately 18 months to 135 patients with parkinsonian disorders: 86 with idiopathic Parkinson's disease (PD), 30 with progressive supranuclear palsy (PSP), 19 with corticobasal degeneration (CBD). We assessed differences between groups for ACE-R, ACE-R subscores and Mini Mental State Examination (MMSE) scores at baseline (analyses of variance, receiver operating characteristics curves), and the interaction between diagnosis and change in ACE-R scores between visits (analyses of variance).
  
  
  RESULTS
  The ACE-R verbal fluency subscore distinguished between PSP and PD with a high sensitivity (0.92) and specificity (0.87); total ACE-R score and the visuospatial subscore were less specific (0.87 and 0.84 respectively) and sensitive (0.70 and 0.73). Significant group level differences were found between PD and PSP for MMSE and ACE-R (total score and subscores for attention and concentration, fluency, language, and visuospatial function), and between PD and CBD for the ACE-R visuospatial subscore. Performance worsened between visits for ACE-R score in PD (p=0.001) and CBD (p=0.001); visuospatial subscore in PD (p=0.003), PSP (p=0.022) and CBD (p=0.0002); and MMSE in CBD (p=0.004).
  
  
  CONCLUSIONS
  We propose the ACE-R, particularly the verbal fluency subscore, as a valuable contributor to the differential diagnosis of parkinsonian syndromes in the correct clinical context. The ACE-R may reflect disease progression in PD and CBD.
authors.affiliation: Department of Clinical Neurosciences, University of Cambridge, Herchel Smith Building, Forvie Site, Addenbrooke's Hospital Site, Robinson Way, Cambridge CB2 0SZ, UK. tr332@medschl.cam.ac.uk
authors.forename: Timothy
authors.initials: T
authors.lastname: Rittman
authors.forename: Boyd C
authors.initials: BC
authors.lastname: Ghosh
authors.forename: Peter
authors.initials: P
authors.lastname: McColgan
authors.forename: David P
authors.initials: DP
authors.lastname: Breen
authors.forename: Jonathan
authors.initials: J
authors.lastname: Evans
authors.forename: Caroline H
authors.initials: CH
authors.lastname: Williams-Gray
authors.forename: Roger A
authors.initials: RA
authors.lastname: Barker
authors.forename: James B
authors.initials: JB
authors.lastname: Rowe
mesh_terms: D000368:Aged; D001288:Attention / Q000502:physiology; D001480:Basal Ganglia Diseases / Q000175:diagnosis; D003071:Cognition / Q000502:physiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007802:Language; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D020734:Parkinsonian Disorders / Q000175:diagnosis* / Q000523:psychology; D012372:ROC Curve; D013028:Space Perception / Q000502:physiology; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis; D014705:Verbal Behavior / Q000502:physiology; D014796:Visual Perception / Q000502:physiology