Corticobasal Syndrome (CBS) is a progressive condition affecting the cortex or grey matter (outer surface) of the brain. This part of the brain is most concerned with higher level cognition. CBS also affects the basal ganglia and brainstem, which are deeper structures in the brain responsible for the smooth execution of movements. Because CBS affects the parts of the brain responsible for both cognitive function and movement, both of these abilities may be affected in this condition. Coticobasal Syndrome can often be confused with Parkinson’s disease, as individuals with CBS may move slowly, be rigid in their movements, and have a tremor.
Individuals with CBS may show any of the following cognitive and movement symptoms:
Additionally, some people with CBS may go on to develop language difficulties. They may speak slowly or have slurred speech. There might be problems with putting words in the right order, or leaving out words. They may also have difficulty with grammar or spelling when writing. In these cases, the individual may be diagnosed with a non-fluent variant of primary progressive aphasia (nfvPPA).
Most people with CBS will begin to display symptoms around age 60, although symptom onset may be as early as 40. The underlying microscopic pathology of CBS is varied. Most often this includes abnormal deposits of the misfolded protein tau; this is called corticobasal degeneration. However, microscopic evaluation of the brain may reveal Alzheimer’s disease-associated plaques and tangles in the same cortical and basal ganglia regions, thus mimicking corticobasal degeneration pathology.