Exploration of motor cortex excitability in a diabetic patient with hemiballism-hemichorea.

Hemiballism-hemichorea in older patients with hyperglycemia, associated with high signal intensity in the contralateral striatum on T1-weighted magnetic resonance scans, is now an accepted clinical entity. We present an additional patient with this disorder. Using transcranial magnetic stimulation, we show that intracortical inhibition in the motor cortex contralateral to hemiballism-hemichorea is increased. This finding is discussed in the context of current models of basal ganglia-thalamo-cortical connectivity.