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Corticobasal degeneration (CBD) is a rare neurodegenerative disorder that affects subcortical, then cortical brain areas. It presents in the sixth or seventh decade with a slowly progressive, unilateral jerky, tremulous, akinetic, rigid and apraxic limb held in a fixed dystonic posture and displaying the alien limb syndrome. The behavioral manifestations may also include language disturbances and frontal-lobe-type behavior. Symptoms and presentations are variable. Clinical symptoms are shared with other neurodegenerative disorders, especially progressive supranuclear palsy (PSP): resistance to L-dopa, myoclonus, action tremor, balance disturbances, pseudobulbar palsy, supranuclear gaze palsy and cognitive impairment. Neuropathological examination shows neurofibrillary tangles in subcortical and frontoparietal cortical areas. There is also a gliosis, a neuronal loss and a presence of achromatic ballooned neurons. At the biochemical level, the profile of neurofibrillary tangles is similar to PSP: it consists in an aggregation of tau proteins with an electrophoretic profile (doublet tau 64 and tau 69) exclusively composed of tau isoforms with exon 10 (tauopathy type 2). There is no treatment available to slow the course of corticobasal degeneration, and the symptoms of the disease are generally resistant to therapy. Occupational, physical, and speech therapy can help in managing disability. |