Corticobasal syndrome
Corticobasal syndrome (CBS) is a rare, progressive atypical Parkinsonism syndrome and is a tauopathy related to frontotemporal dementia. CBS is typically caused by the deposit of tau proteins forming in different areas of the brain. Classification CBS is the most common type of corticobasal degeneration (CBD) although the terms CBD and CBS have been used interchangeably in the past. The other three phenotypes of CBD are: frontal-behavioral dysexecutive-spatial syndrome (FBS) nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and progressive supranuclear palsy syndrome (PSPS). Symptoms and signs Symptoms of CBS include apraxia, alien limb phenomenon, frontal deficits, and extrapyramidal motor symptoms such as myoclonus or rigidity. Movement deficits often begin on one side and progress to the other. Pathophysiology CBD is the pathology underlying approximately 50% of CBS cases. Diagnosis The Armstrong criteria were proposed in 2013; the accuracy of these is limited and further research is needed. Symptoms may be symmetric or asymmetric, with one or more of the following: 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