title: Validation of the new consensus criteria for the diagnosis of corticobasal degeneration.
abstract: BACKGROUND
  Corticobasal degeneration (CBD) is a complex neurodegenerative disorder. Accurate diagnosis is increasingly important, with the advent of clinical trials of drugs aimed at modifying the underlying tau pathology. CBD often presents with a 'corticobasal syndrome' including impairments of movement and cognition. However, patients with similar corticobasal syndromes can have neurodegenerative pathologies that are not CBD. In addition, patients with CBD may present with aphasia or behavioural change. The clinical diversity of CBD and mimicry by non-CBD pathologies hinders accurate diagnosis.
  
  
  METHODS
  We applied the new consensus criteria of Armstrong and colleagues et al 1 to a cohort of patients with detailed longitudinal clinical evaluation and neuropathology.
  
  
  RESULTS
  In patients with pathologically confirmed CBD, accuracy of diagnosis was similar under the new and previous criteria: 9/19 (47%) met criteria for probable CBD at presentation, 13/19 (68%) at last clinical assessment. Patients with a corticobasal syndrome but without CBD pathology all (14/14) met the new diagnostic criteria of probable or possible CBD, demonstrating that the new criteria lacks the necessary specificity for an accurate ante mortem clinical diagnosis of CBD. None of the clinical features used in the new criteria were more common in the patients with CBD pathology (n=19) than without (n=14).
  
  
  CONCLUSIONS
  The Armstrong criteria usefully broadens the recognised clinical phenotype of CBD but does not sufficiently improve the specificity of diagnosis to increase the power of clinical trials or targeted applications of tau-based disease-modifying therapies. Further work is required to show whether biomarkers could be more effective than clinical signs in the diagnosis of CBD.
authors: Addenbrooke's Hospital, Cambridge, UK.
authors: S K
authors: SK
authors: Alexander
authors: Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors: T
authors: T
authors: Rittman
authors: Department of Pathology, University of Cambridge, Cambridge, UK.
authors: J H
authors: JH
authors: Xuereb
authors: School of Philosophy, Psychology and Language Sciences, University of Edinburgh, Edinburgh, UK.
authors: T H
authors: TH
authors: Bak
authors: Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia.
authors: J R
authors: JR
authors: Hodges
authors: Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors: J B
authors: JB
authors: Rowe
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D001479:Basal Ganglia / Q000473:pathology; D001480:Basal Ganglia Diseases / Q000175:diagnosis / Q000473:pathology / Q000523:psychology; D015415:Biomarkers; D001921:Brain / Q000473:pathology; D003937:Diagnosis, Differential; D019636:Neurodegenerative Diseases / Q000175:diagnosis / Q000473:pathology / Q000523:psychology; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis; D016875:tau Proteins / Q000737:chemistry / Q000378:metabolism; D014015:Tissue Banks; D006113:United Kingdom; D003245:Consensus Statements as Topic
chemical_list: D015415:Biomarkers; D016875:tau Proteins
keywords: Alzheimer'S Disease; Corticobasal Degeneration; Dementia; Neuropathology