부산대학교 도서관

Background; During neurosurgical treatment, it is extremely important to localize of cerebral function to preserve cerebral function and maintain the quality of life of the patients. Recently, hemispheric dominance for language has been assessed using the Wada test in which amobarbital is injected into the carotid artery. However, this is an invasive technique with considerable risk of complications. Herein, we attempted optical topography (OT) along with the findings of the Wada test.Methods; Eleven patients who underwent craniotomy in this hospital were tested with optical topography during a word generation task. These patients included 3 patients with cerebral aneurysms, 6 with brain tumor, 1 with epilepsy, 1 with cerebral arteriovenous malformation, who were from 13 year to 81 years of age, and comprised of 7 men and 4 women.Word generation task: Each subject was given 15 seconds to write down as many words as possible, beginning with a randomly presented letter on a computer monitor. In between presentation of letters, subjects were instructed to focus on copying a picture for 30 seconds during which the NIRS baseline was established.NIRS measurements: We measured the relative changes in oxygenated (Oxy-Hb) deoxygenated hemoglobin (deoxy-Hb) and total hemoglobin, which were calculated by combining the two parameters following collection of NIRS data (ETG-7100; Hitachi Medical Corporation, Tokyo, Japan) during performance of the Word generation task. We subsequently used a region of interest (ROI) and laterality index (LI). Six ROIs were set to determine the useful ROI, and the agreement rate with the Wada test was calculated. The LI, for Oxy-Hb was calculated from L and R, the sum of the concentrations for the activated ROIs over the left and right inferior frontal regions bilaterally, according to the following formula: LI= (L−R)/(L+R). The LI ranged from −1 to 1, where a positive value (0.26 to 1) indicated left language lateralization and a negative value (−1 to −0.26) indicated right language lateralization. A value between −0.25 and 0.25 inclusively was considered to reflect bilateral language dominance.Results; The results indicated a high agreement ratio in ROI 3, 5, and 6, of which 5 and 6 were included in ROI 3. We subsequently determined the language dominant hemisphere from the foregoing ROI and LI. The results based upon the optical topography were eight left-sided predominance, right predominance in two, and one case of bilateral predominance. Meanwhile, the results of Wada test were eight left-sided predominance, one case each of right and bilateral predominance, and inability to determine in one. The agreement between the techniques was 90% (9/10 case). One evaluation that was impossible by determination using Wada test was possible.Conclusions; Therefore, this study demonstrates that OT is a feasible clinical application for the identification of the language dominant hemisphere.