Localization of motor speech area by functional MRI during word generation

Jeong, Sang Wuk; Song, In Chan; Lee, Kyung Min; Lee, Sang Kun; Chang, Kee Hyun

Abstract

BACKGROUND: Until recently lateralization or localization of language area was possible only by electrical stimulation or Wada test. We describe here a convenient and noninvasive method of language localization with functional magnetic resonance image (MRI). METHOD: Twelve healthy right-handed Korean young volunteers (M:F=9:3, mean age: 24 years) were recruited for this study. We collected brain activation image of 6 slice using gradient echo EPI (Echo-planar imaging) during 8 sets of resting and activation periods. During resting periods, each of 10 Korean nouns composed of two to four syllables was shown continuously every 3 seconds and the subjects were required to simply read the words. The activation task was to generate words as many as possible beginning with the same initial syllable seen on screen without any movement. The data were analyzed using SPM (statistical parametric mapping) and the activated signals were overlayed on a T1-weighed image. RESULT: The activated areas were observed in the perisylvian areas including inferior frontal gyrus and middle superior temporal gyri in 9 subjects. (left in 7, right in 2) Another one subject showed nonsignificant activation in left pre-& postcentral gyrus. The remaining two subjects showed only motion artifacts. Therefore, except motion artifact we localized motor speech areas in 9 of 10 subjects.
CONCLUSION
Activation of motor speech area is observed by functional MRI using EPI technique efficiently, quickly and noninvasively. Such functional mapping may have value for the neurosurgical planning.