Is progressive upper-body apraxia a corticobasal syndrome?

Corticobasal degeneration (CBD) is characterized by various clinical manifestations including corticobasal syndrome, progressive supranuclear palsy-like syndrome and frontotemporal dementia. Focal cortical atrophy syndrome as the initial manifestation rarely occurs in CBD. Here, we present a 62-year-old man and a 70-year-old man who were admitted due to clumsiness in the arms. On initial neurological examination, they showed asymmetric limb apraxia without parkinsonism or global cognitive dysfunction. Brain MRI showed focal atrophy in the frontal and prefrontal cortices, and brain positron emission tomography scan revealed decreased metabolism in these same brain locations. Although these patients developed parkinsonism and dystonia within several years, the neurological signs were limited to the arms for a long period. "Progressive upper-body apraxia" may be a rare clinical manifestation of CBD which shows a benign clinical outcome. The patients described may enhance our understanding of the clinical heterogeneity of this disease.