Corticobasal degeneration (CBD) is a complex neurodegenerative disorder which nomenclature of which its nomenclature and characterization continues to evolve. The core clinical features that have been considered characteristic of the disorder include progressive asymmetric rigidity and apraxia, with other findings suggesting additional cortical (e.g., alien limb phenomena, cortical sensory loss, myoclonus, and mirror movements) and basal ganglionic (e.g., bradykinesia, dystonia, and tremor) dysfunctions. The characteristic findings at autopsy are asymmetric cortical atrophy that is typically maximal in the frontoparietal regions, as well as basal ganglia and nigral degeneration. Microscopically, abnormal accumulations of the microtubule-associated tau protein are found in both neurons and glia, and this disorder is now considered one of the “tauopathies.” CBD was initially thought to represent a distinct clinicopathologic entity. Recent studies have shown considerable clinicopathologic heterogeneity, leading some to use the term “corticobasal syndrome” (CBS) for the constellation of findings initially considered characteristic of the disorder, and the term “corticobasal degeneration” for the histopathologic disorder. In this review, the multiple phenotypes/syndromes associated with CBD pathology, and multiple diseases associated with the CBS, are presented. The clinicopathologic heterogeneity in CBS/CBD and the implications of this heterogeneity on clinical practice, on understanding the focal/asymmetric cerebral degeneration syndromes, and on future research are all reviewed.
Corticobasal degeneration Corticobasal syndrome Apraxia Alien limb phenomenon Tau
This study was supported by grants AG06786 and AG16574 from the National Institute on Aging. The author thanks his many colleagues for their ongoing support and collaborations in CBS/CBD research, and particularly extends his appreciation to the patients and their families for participating in research on CBS/CBD.
Boeve B (2005) Corticobasal degeneration: the syndrome and the disease. In: Litvan I (ed) Atypical parkinsonian disorders. Humana, Totawa, pp 309–334CrossRefGoogle Scholar
Boeve B (2007) Links between frontotemporal lobar degeneration, corticobasal degeneration, progressive supranuclear palsy, and amyotrophic lateral sclerosis. Alzheimer Dis Assoc Disord 21:S31–S38PubMedCrossRefGoogle Scholar
Boeve BF, Maraganore DM, Parisi JE et al (1999) Pathologic heterogeneity in clinically diagnosed corticobasal degeneration. Neurology 53:795–800PubMedGoogle Scholar
Boeve B, Lang A, Litvan I (2003) Corticobasal degeneration and its relationship to progressive supranuclear palsy and frontotemporal dementia. Ann Neurol 54:S15–S19PubMedCrossRefGoogle Scholar
Caselli R, Jack C (1992) Asymmetric cortical degeneration syndromes: a proposed clinical classification. Arch Neurol 49:770–780PubMedGoogle Scholar
Caselli R, Jack C, Petersen R (1992) Asymmetric cortical degeneration syndrome: clinical and radiologic correlations. Neurology 42:1462–1468PubMedGoogle Scholar
Dickson D, Bergeron C, Chin S et al (2002) Office of Rare Diseases neuropathologic criteria for corticobasal degeneration. J Neuropathol Exp Neurol 61:935–946PubMedGoogle Scholar
Gibb W, Luthert P, Marsden C (1990) Clinical and pathologic features of corticobasal degeneration. In: Streifler M, Korczyn A, Melamed E, Youdim M (eds) Advances in neurology: Parkinson’s disease: anatomy, pathology, and therapy. Raven, New York, pp 51–54Google Scholar
Hassan A, Whitwell J, Boeve B et al (2010) Symmetric corticobasal degeneration (S-CBD). Parkinsonism Relat Disord 16:208–214PubMedCrossRefGoogle Scholar
Josephs K, Duffy J, Strand E et al (2006a) Clinicopathological and imaging correlates of progressive aphasia and apraxia of speech. Brain 129:1385–1398PubMedCrossRefGoogle Scholar
Josephs KA, Petersen RC, Knopman DS et al (2006b) Clinicopathologic analysis of frontotemporal and corticobasal degenerations and PSP. Neurology 66:41–48PubMedCrossRefGoogle Scholar