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Research paper
Validation of the new consensus criteria for the diagnosis of corticobasal degeneration
  1. S K Alexander1,
  2. T Rittman2,
  3. J H Xuereb3,
  4. T H Bak4,
  5. J R Hodges5,
  6. J B Rowe2
  1. 1Addenbrooke's Hospital, Cambridge, UK
  2. 2Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
  3. 3Department of Pathology, University of Cambridge, Cambridge, UK
  4. 4School of Philosophy, Psychology and Language Sciences, University of Edinburgh, Edinburgh, UK
  5. 5Neuroscience Research Australia, University of New South Wales, Sydney, New South Wales, Australia
  1. Correspondence to Dr S K Alexander, Addenbrooke's Hospital, Box 154, Hills Road, CB4 1RS, Cambridge CB2 0QQ, UK; sa636{at}cam.ac.uk

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.

  • Alzheimer'S Disease
  • Dementia
  • Neuropathology
  • Corticobasal Degeneration

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 3.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/3.0/

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