Cortical excitability and ischemia in patients with chronic unilateral internal carotid artery occlusion

Relationships between cortical excitability and regional cerebral blood flow (rCBF) were investigated in eight patients with chronic internal carotid artery occlusion using somatosensory evoked field recovery function (SEF-R). At interstimulus intervals (ISIs) of 120 and 160 ms, the SEF-R curve of the affected hemisphere demonstrated a significant overshoot above that of the non-affected hemisphere, suggesting cortical hyperexcitability. Furthermore, the rCBF at the hand area of the primary sensory area and the SEF-R at the ISI of 160 ms were inversely correlated. These results suggest that cortical hyperexcitability occurs at the primary sensory area in association with the severity of ischemia in the patients with chronic ICA occlusion.