Corticobasal syndrome / corticobasal degeneration
Diagnosis
CBS clinical criteria 111 (note that other clinical phenotypes, including FBS, naPPA, and PSP may also have CBD pathology)
1) Probable CBS
- a. Must have asymmetric presentation
- b. Must have at least two of the following:
- i. Limb rigidity or akinesia
- ii. Limb dystonia
- iii. Limb myoclonus
- c. Must have at least two of the following:
- i. Orobuccal or limb apraxia
- ii. Cortical sensory deficit (i.e. agraphesthesia, astereognosis)
- iii. Alien limb phenomena (more than simple levitation)
2) Possible CBS
- a. Must have asymmetric presentation
- b. Must have at least one of the following:
- i. Limb rigidity or akinesia
- ii. Limb dystonia
- iii. Limb myoclonus
- c. Must have at least one of the following:
- i. Orobuccal or limb apraxia
- ii. Cortical sensory deficit
- iii. Alien limb phenomena (more than simple levitation)
- patients with CBS will often have deficits within domains of executive functioning, writing, as and visuospatial construction 95
- neuroimaging shows asymmetric frontal and parietal lobe atrophy 95
Other possible presentations of underlying corticobasal degeneration pathology: 111
1) Frontal behavioral-spatial syndrome
- a. Must have at least two of the following:
- i. Executive dysfunction
- ii. Behavioral or personality changes
- iii. Visuospatial deficits
2) Non-fluent/agrammatic PPA (naPPA), see PPA chapter
3) PSP syndrome, see PSP
Pathology
Proposed pathologic criteria for the diagnosis of CBD require: 111
- a) The detection of characteristic tau-immunoreactive lesions in the neurons, glia, and cell processes of the cortex and striatum (caudate and putamen), particularly astrocytic plaques and thread-like lesions in both white matter and gray matter
- b) In conjunction with neuronal loss in focal cortical regions and in the substantia nigra
- c) Supportive features include ballooned cortical neurons, cortical atrophy, and tau-positive oligodendroglial coiled bodies
- pathology is typically 4R tau (CBD) > (Alzheimer’s pathology) > PSP, TDP-43 > 3R tau 92
