[Ictal SPECT and paired stimulation SEP recovery curve in a patient with paroxysmal kinesigenic choreoathetosis].

Paroxysmal kinesigenic choreoathetosis (PKC) is a rare and benign disorder with its onset in childhood. PKC generally improves with age, and its pathophysiology has not been revealed. We recorded both ictal and interictal SPECT in a 14-year-old girl with PKC. Ictal SPECT showed a significant decrease in blood flow in the caudate nucleus contralateral to the limb showing an involuntary movement. We also examined paired-pulse stimuli somatosensory evoked potential (SEP) of the same patient. Recovery pattern of P25 and N33 components was normal and comparable to 5 healthy volunteers, suggesting the absence of cortical hyperexcitability. These results suggest dysfunction or immaturity of the indirect pathway of basal ganglia in PKC, as well as the hyperexcitability of the descending pathway.