Diagnosis of CBS

CBS is diagnosed on the basis of a clinical examination by a physician, usually a neurologist or a psychiatrist. The diagnosis of CBS is made in the context of the history, cognitive examination, and neurological examination.  

Neuropathologic assessment at autopsy remains the only certain means to diagnose corticobasal degeneration (CBD), one of several neuropathologic causes of CBS.  

There are no definitive biomarkers for CBD, though some imaging modalities can provide supportive data.

• A magnetic resonance imaging (MRI) image of the brain can reveal asymmetric “atrophy” or shrinking in and around areas that subserve motor function.
• Functional imaging, specifically fluorodeoxyglucose-positron emission tomography (FDG-PET) or single-photon emission computed tomography (SPECT), can reveal asymmetrically decreased activity in the brain.
• A dopamine transporter (DaT) SPECT can be abnormal in CBD, though this study does not discriminate CBD from other pathologies, such as Parkinson’s disease, Lewy Body disease, multiple system atrophy, and progressive supranuclear palsy (PSP).  

Finally, a lumbar puncture and cerebrospinal fluid analysis can diagnose underlying Alzheimer’s disease, another possible cause of CBS.