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]
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]
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]
limb rigidity or akinesia
limb dystonia
limb myoclonus, plus one of:
orobuccal or limb apraxia
cortical sensory deficit
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:
limb rigidity or akinesia
limb dystonia
limb myoclonus
plus two of:
orobuccal or limb apraxia,
cortical sensory deficit
alien limb phenomena (more than simple levitation)[8]
The diagnosis is excluded if there is evidence of:
^Fredericks CA, Lee SE (2016). "The cognitive neurology of corticobasal degeneration and progressive supranuclear palsy". In Miller, Bruce L.; Boeve, Bradley F. (eds.). The Behavioral Neurology of Dementia (Second ed.). Cambridge, United Kingdom: Cambridge University Press. pp. 203–6. ISBN9781107077201. OCLC934020279. [CBD is] reminiscent of classic CBS but with executive function deficits
