Medicine:Corticobasal syndrome

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Short description: Medical condition

Corticobasal syndrome (CBS) is a rare, progressive atypical Parkinsonism syndrome and is a tauopathy related to frontotemporal dementia.[1][2] CBS is typically caused by the deposit of tau proteins forming in different areas of the brain.[1][3]


CBS is the most common type of corticobasal degeneration (CBD) although the terms CBD and CBS have been used interchangeably in the past.[2] The other three phenotypes of CBD are:[1]

  • frontal-behavioral dysexecutive-spatial syndrome (FBS)
  • nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and
  • progressive supranuclear palsy syndrome (PSPS).[1][4]

Symptoms and signs

Symptoms of CBS include apraxia, alien limb phenomenon, frontal deficits, and extrapyramidal motor symptoms such as myoclonus or rigidity.[5] Movement deficits often begin on one side and progress to the other.[1]


CBD is the pathology underlying approximately 50% of CBS cases.[6]


The Armstrong criteria were proposed in 2013; the accuracy of these is limited and further research is needed.[7] Symptoms may be symmetric or asymmetric, with one or more of the following:[citation needed]

  1. limb rigidity or akinesia
  2. limb dystonia
  3. limb myoclonus, plus one of:
  4. orobuccal or limb apraxia
  5. cortical sensory deficit
  6. alien limb phenomena (more than simple levitation)

The onset is insidious with gradual progression, lasting one year or more, with no exclusion criteria present. The diagnosis is more likely if onset is after age 50, there is no family history (2 or more relatives),[clarification needed] and there is no genetic mutation affecting T[clarification needed] (e.g., MAPT).[8]

Probably sporadic CBS is more likely if there are two of:

  1. limb rigidity or akinesia
  2. limb dystonia
  3. limb myoclonus
  • plus two of:
  1. orobuccal or limb apraxia,
  2. cortical sensory deficit
  3. alien limb phenomena (more than simple levitation)[8]

The diagnosis is excluded if there is evidence of:

The diagnostic criteria for clinical use may result in a misdiagnosis of other tau-based diseases.[7]

The probable criteria are proposed for clinical research.[7]


Other degenerative pathologies that can cause corticobasal syndrome include:

The symptoms of classic CBS differ from CBD in that CBD also includes cognitive deficits in the executive functions.[10]


The average survival time after disease onset is estimated at 6.5 years.[2]


  1. 1.0 1.1 1.2 1.3 1.4 "Corticobasal syndrome: A diagnostic conundrum". Dementia Neuropsychologia 10 (4): 267–75. 2016. doi:10.1590/s1980-5764-2016dn1004003. PMID 29213468. 
  2. 2.0 2.1 2.2 "Corticobasal degeneration and corticobasal syndrome: A review". Clinical Parkinsonism & Related Disorders 1: 66–71. August 2019. doi:10.1016/j.prdoa.2019.08.005. ISSN 2590-1125. PMID 34316603. 
  3. "Corticobasal syndrome: neuroimaging and neurophysiological advances". Eur. J. Neurol. 26 (5): 701–e52. May 2019. doi:10.1111/ene.13928. PMID 30720235. 
  4. "Criteria for the diagnosis of corticobasal degeneration". Neurology 80 (5): 496–503. January 2013. doi:10.1212/WNL.0b013e31827f0fd1. PMID 23359374. 
  5. "Frontotemporal Dementias". Continuum (Minneap Minn) 22 (2 Dementia): 464–89. April 2016. doi:10.1212/CON.0000000000000300. PMID 27042904. 
  6. "Lewy Body Dementias: Dementia With Lewy Bodies and Parkinson Disease Dementia". Continuum (Minneap Minn) 22 (2 Dementia): 435–63. April 2016. doi:10.1212/CON.0000000000000309. PMID 27042903. 
  7. 7.0 7.1 7.2 "[Diagnoses of corticobasal syndrome and corticobasal degeneration]" (in ja). Rinsho Shinkeigaku 56 (3): 149–57. 2016. doi:10.5692/ PMID 26876110. 
  8. 8.0 8.1 8.2 "Validation of the new consensus criteria for the diagnosis of corticobasal degeneration". J. Neurol. Neurosurg. Psychiatry 85 (8): 925–29. August 2014. doi:10.1136/jnnp-2013-307035. PMID 24521567. 
  9. "The corticobasal syndrome-Alzheimer's disease conundrum". Expert Rev Neurother 11 (11): 1569–78. November 2011. doi:10.1586/ern.11.153. PMID 22014136. 
  10. Fredericks CA, Lee SE (2016). "The cognitive neurology of corticobasal degeneration and progressive supranuclear palsy". in Miller, Bruce L.. The Behavioral Neurology of Dementia (Second ed.). Cambridge, United Kingdom: Cambridge University Press. pp. 203–6. ISBN 9781107077201. OCLC 934020279. "[CBD is] reminiscent of classic CBS but with executive function deficits"