[Corticobasal degeneration: symptomatological, brain-imaging and electrophysiological studies]

Eight cases of clinically diagnosed corticobasal degeneration (CBD) were studied with reference to their symptomatology, brain-imagings and electrophysiological findings. The diagnosis was based on the combination of limb-kinetic apraxia (cortical sign), akinetic-rigid sign (extrapyramidal) and their unilateral predominance. Magnetic resonance imaging (MRI) and 123I-IMP or 99mTc-HMPAO SPECT findings were used to reinforce the diagnosis. The age at onset of 8 cases (4 males, 4 females) was 61 to 80 years (mean 66). Other common symptoms on admission consisted of dysequilibrium (8 cases), dysarthria (8), grasp reflex (6), supranuclear gaze palsy (6), tremor (6), limb dystonia (6) and alien limbs (5). MRI revealed parietal (3 cases) or frontoparietal (3) atrophy. SPECT showed decrease in cerebral blood flow in frontoparietal (3 cases) or frontoparietotemporal lobes (5). SPECT surpassed MRI to detect unilateral predominance of the lesions. With magnetic stimulation of the head and neck central motor conduction time (CMCT) was normal, while motor inhibitory periods (IPs) were significantly shorter in CBD patients compared with those in normal controls and the patients with Parkinson's disease. In 3 patients with reflex myoclonus, giant SEPs were not evoked, though with positive C-reflex, suggesting an elevated excitability of cerebral cortex unrelated to the production of giant SEPs.