corticobasal

Corticobasal refers to a clinical syndrome (corticobasal syndrome, CBS) and to corticobasal degeneration (CBD), a neurologic disease. CBS describes a heterogeneous presentation with asymmetric motor and cortical symptoms, while CBD is a distinct neurodegenerative tauopathy that can underlie CBS.

Typical CBS features include asymmetric limb rigidity and dystonia, myoclonus, apraxia (difficulty performing skilled movements), alien limb phenomenon, cortical sensory loss, and visuospatial or language difficulties. Symptoms are often unilateral early in the disease and progressively spread.

Corticobasal degeneration is characterized by 4-repeat tau pathology affecting the cerebral cortex and basal ganglia. CBD is a specific pathologic entity; however, the clinical syndrome CBS can be caused by other diseases, such as Alzheimer's disease, Lewy body disease, frontotemporal lobar degeneration, or vascular disease.

Diagnosis of CBS is clinical; imaging supports asymmetric involvement. MRI may show focal atrophy in frontoparietal regions; FDG-PET or SPECT may reveal asymmetric hypometabolism. A definite diagnosis of CBD requires neuropathologic confirmation after death.

There is no cure for CBD or CBS. Management is supportive and multidisciplinary, including physical, occupational, and speech therapy; dopaminergic medications may yield transient improvement in some motor symptoms; botulinum toxin can help focal dystonia; pain management and assistive devices may be used. The course is progressive and variable, typically lasting several years from onset.

Context: CBS is the clinical syndrome; CBD refers to the pathology most commonly associated with it, but other diseases may present as CBS.