This is a terrific article reviewing all of the cases in the Queen Square Brain Bank in London with a pathologically confirmed CBD diagnosis (19) or a clinical diagnosis of CBS (21). In both cases, the diagnostic accuracy was about 25%. Of “21 cases with a clinical diagnosis of corticobasal syndrome, only five had corticobasal degeneration pathology, giving a positive predictive value of 23.8%; six others had progressive supranuclear palsy pathology, five had Alzheimer’s disease and the remaining five had other non-tau pathologies.”
New terminology is proposed for a large group of pathologically confirmed CBD cases: “Corticobasal degeneration can present very commonly with a clinical picture closely resembling classical progressive supranuclear palsy or Richardson’s syndrome, and we propose the term corticobasal degeneration-Richardson’s syndrome for this subgroup. Cases of corticobasal degeneration-Richardson’s syndrome have delayed onset of vertical supranuclear gaze palsy (>3 years after onset of first symptom) and the infrequent occurrence of predominant downgaze abnormalities, both of which can be helpful pointers to their underlying corticobasal degeneration pathology. Fourty-two per cent of corticobasal degeneration cases presented clinically with a progressive supranuclear palsy phenotype and 29% of cases with corticobasal syndrome had underlying progressive supranuclear palsy pathology.”
The researchers conclude: “Despite these diagnostic difficulties we conclude that corticobasal degeneration is a discrete clinicopathological entity but with a broader clinical spectrum than was originally proposed.”
This UK team consistently produces great research articles. I wish we could get these sorts of brain bank reports out of any US institution with large numbers of CBD and PSP brains. I think Mayo Jax has nearly 100 CBD brains.
Robin
Brain. 2010 Jul;133(Pt 7):2045-57.
Does corticobasal degeneration exist? A clinicopathological re-evaluation.
Ling H, O’Sullivan SS, Holton JL, Revesz T, Massey LA, Williams DR, Paviour DC, Lees AJ.
Reta Lila Weston Institute of Neurological Studies, Institute of Neurology, University College London, London, UK.
Abstract
The pathological findings of corticobasal degeneration are associated with several distinct clinical syndromes, and the corticobasal syndrome has been linked with a number of diverse pathologies.
We have reviewed all the archival cases in the Queen Square Brain Bank for Neurological Disorders over a 20-year period with either a clinical diagnosis of corticobasal syndrome or pathological diagnosis of corticobasal degeneration in an attempt to identify the main diagnostic pitfalls.
Of 19 pathologically confirmed corticobasal degeneration cases, only five had been diagnosed correctly in life (sensitivity = 26.3%) and four of these had received an alternative earlier diagnosis. All five of these had a unilateral presentation, clumsy useless limb, limb apraxia and myoclonus, four had cortical sensory impairment and focal limb dystonia and three had an alien limb. Eight cases of corticobasal degeneration had been clinically diagnosed as progressive supranuclear palsy, all of whom had vertical supranuclear palsy and seven had falls within the first 2 years.
On the other hand, of 21 cases with a clinical diagnosis of corticobasal syndrome, only five had corticobasal degeneration pathology, giving a positive predictive value of 23.8%; six others had progressive supranuclear palsy pathology, five had Alzheimer’s disease and the remaining five had other non-tau pathologies.
Corticobasal degeneration can present very commonly with a clinical picture closely resembling classical progressive supranuclear palsy or Richardson’s syndrome, and we propose the term corticobasal degeneration-Richardson’s syndrome for this subgroup. Cases of corticobasal degeneration-Richardson’s syndrome have delayed onset of vertical supranuclear gaze palsy (>3 years after onset of first symptom) and the infrequent occurrence of predominant downgaze abnormalities, both of which can be helpful pointers to their underlying corticobasal degeneration pathology. Fourty-two per cent of corticobasal degeneration cases presented clinically with a progressive supranuclear palsy phenotype and 29% of cases with corticobasal syndrome had underlying progressive supranuclear palsy pathology.
In contrast, in the Queen Square Brain Bank archival collection, corticobasal syndrome is a rare clinical presentation of progressive supranuclear palsy occurring in only 6 of the 179 pathologically diagnosed progressive supranuclear palsy cases (3%).
Despite these diagnostic difficulties we conclude that corticobasal degeneration is a discrete clinicopathological entity but with a broader clinical spectrum than was originally proposed.
PubMed ID#: 20584946 (see pubmed.gov for this abstract only)