Corticobasal degeneration

Abstract

Corticobasal degeneration (CBD) is a slowly progressive neurodegenerative process, which begins in adulthood and typically presents with asymmetrical parkinsonism and cognitive dysfunction. It is currently classified as a tauopathy. Neuropathological findings show an important loss of cortical neurons that is predominantly asymmetrical and multifocal until very advanced phases of the disease, more often in the frontal-parietal regions. It is a syndrome with a wide clinical diversity and a progression that will be marked by the asymmetry of the main symptoms. Cognitive disorder may be a common presenting symptom and a range of clinical phenomena have been identified, depending on the topography of the degenerative area. It is typically characterised by a marked rigidity and hypokinesia, dystonia with predominance in one extremity, cortical reflex myoclonus, pyramidal signs and postural or action coarse tremor. Also prominent are apraxic deficits, cortical sensory deficit and the so-called alien limb phenomenon, which, although less frequent, is considered characteristic when it does appear. Diagnosis is fundamentally clinical and based on the diagnostic criteria of corticobasal syndrome put forward in the year 2003 and with the support of complementary tests. Differential diagnosis should be considered with Parkinson-Plus as well as with the primary degenerative dementias with predominance of frontal and/or temporal symptoms, more especially with PSP and fronto-temporal dementia. CBD progresses in 3-15 years towards the death of the individual, normally as a consequence of complications deriving from immobility.