Correlation of Evoked Potentials and Regional Cerebral Blood Flow in SAH Patients with Vasospasm

Lim, Young Jin; Kim, Tae Sung; Kim, Kwang Myung; Rhee, Bong Arm; Kim, Gook Ki; Leem, Won

Abstract

With 4 channel Nicolet-CA 1000 clinical averager and 133 Xenon inhalation method, somatosensory evoked potentials (SSEP), brainstem auditory evoked potentials (BAEP) and regional cerebral blood flow (r-CBF) were studied in 30 patients with ruptured cerebral aneurysms. 8 out of 30 patients had abnormal SSEP, 11 out of 30 patients had abnormal BAEP and 4 out of 14 patients had decreased r-CBF. The SSEP was abnormal in 6 out of 10 patients with severe vasospasm but in only 2 out of 20 patients without vasospasm or with mild and moderate spasm. The BAEP was abnormal in 5 out of 10 patients with severe vasospasm but 6 out of 20 patients without spasm or with mild and moderate spasm. Regional CBF was decreased in 3 out of 4 patients with severe vasospasm but only 1 out of 10 patients without spasm or with mild and moderate spasm. Abnormal SSEP, BAEP & decreased r-CBF in patients with severe vasospasm indicated a poor prognosis. We got the results as follows ; 1) Abnormal SSEP, BAEP and decreased r-CBF are correlated with severity of vasospasm in SAH patients. 2) Abnormal SSEP and BAEP correlated with the clinical status. 3) Brain stem transmission time (BTT) is less sensitive than central conduction time (CCT) as indicator of vasospasm.