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Corticobasal degeneration (CBD) is one of the manifests as dementia plus parkinsonism. Symptoms or signs, CBD can be classified into cortical (cortical sensory loss, apraxia, alien limb, frontal release signs, dysphasia, and dementia), movement symptoms (akinetic-rigid syndrome, dysequilibrium, postural-action tremor, limb dystonia, myoclonus, other dyskinesias), and others (hyperreflexia, Babinski signs, supranuclear gaze palsy, levator inhibition, and dysarthria). Of these, essential signs for the diagnosis of CBD especially in its early stage include unilateral limb rigidity, bradykinesia, ideomotor apraxia, postural imbalance, unilateral limb dystonia, and cortical dementia. CT or MRI in patients with CBD usually shows asymmetric atrophy in the parietal and frontal area, which is rather nonspecific. SPECT or PET, in contrast, shows more widespread functional changes involving cortical regions (prefrontal, anterior cingulate, medial premotor, sensorimotor, posterior parietal, and superior temporal) as well as putamen or caudate nucleus. It has been reported that clinically diagnosed CDB patients may disclose histopathologic findings compatible with Alzheimer’s disease, frontotempral dementia, progressive supranuclear palsy, or Creutzfeldt-Jacob disease. Recent achievements in molecular genetic studies in CBD, however, are expected to compliment clinical and neuroimaging findings in enhancing the diagnostic accuracy of CBD.
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