Unusual clinical presentations of cortical-basal ganglionic degeneration.

Cortical-basal ganglionic degeneration classically presents predominantly as a motor disorder with a unique constellation of histological alterations characterized by the presence of neuronal loss and gliosis in a selective distribution, swollen achromasic neurons, and extensive deposition of abnormal tau in neurons and glia. We now report 3 patients with this distinctive pathology who presented with cognitive changes and only mild or delayed motor symptoms. In 2 patients with severe dementia, pathological changes were extensive in the anterior frontal lobe, amygdala, and hippocampus. In a third patient who had an isolated speech disturbance for 5 years before developing the more typical motor features of cortical-basal ganglionic degeneration, the most severe changes were observed in the left motor cortex and adjacent Broca's area. It is therefore apparent that the histological changes of cortical-basal ganglionic degeneration result in a variety of clinical presentations depending on the topography of the lesions. On this basis we conclude that cortical-basal ganglionic degeneration should be considered in the differential diagnosis of language disturbances and dementia, particularly when the latter is accompanied by frontal lobe symptomatology, early speech alterations, or parkinsonism.