Clinical features of corticobasal degeneration

Corticobasal degeneration was described in 1968 by Rebeiz, Kolodny and Richardson, who characterized the disease as a syndrome of asymmetric akinesis and rigidity, dystonia of the upper limb, apraxia, myoclonus and dementia. Atrophy of the frontal and parietal lobe, neuronal loss, gliosis and achromatic neurones (and nowadays astrocytic plaques) are the characteristic pathological features of the disease. Corticobasal degeneration is a rare or a rarely recognized disease and it is frequently misdiagnosed as Parkinson's disease. According to the Lang's criteria, corticobasal degeneration can be diagnosed in the presence of rigidity and one cortical symptom (apraxia, cortical sensory loss, alien hand) or in a patient with rigidity, dystonia and focal reflex myoclonus. Exclusion criteria are early dementia (as in primary degenerative dementias), early vertical gaze problems (as in progressive supranuclear palsy), resting tremor and good, sustained therapeutic response to levodopa (as in Parkinson's disease), severe autonomic problems (as in multiple system atrophy) and any pathology on imaging studies which might explain the clinical symptoms. It should be mentioned, that recently early dementia is recognized as an initial symptom of corticobasal degeneration. The authors present a case and review the literature to call attention to this disorder.