Functional MRI of Motor Speech Area Combined with Motor Stimulation during Resting Period

Lim, Yeong Su; Park, Hark Hoon; Chung, Gyung Ho; Lee, Sang Yong; Chon, Su Bin; Kang, Shin Hwa

Abstract

PURPOSE: To evaluate functional MR imaging of the motor speech area with and without motor stimulation duringthe rest period.
MATERIALS AND METHODS
Nine healthy, right-handed volunteers(M:F=7:2, age:21-40years) wereincluded in this study. Brain activity was mapped using a multislice, gradient echo single shot EPI on a 1.5T MRscanner. The paradigm consisted on a series of alternating rest and activation tasks, performed six times. Each volunteer in the first study(group A) was given examples of motor stimulation during the rest period, while eachin the second study(group B) was not given examples of a rest period. Motor stimulation in group A was achieved bycontinuously flexing five fingers of the right hand. In both groups, maximum internal word generation was achievedduring the activation period. Using fMRI analysis software(Stimulate 5.0) and a cross-correlationmethod(background threshold, 200; correlation threshold, 0.3; ceiling, 1.0; floor, 0.3; minimal count, 3),functional images were analysed. After correlating the activated foci and a time-signal intensity curve, theactivated brain cortex and number of pixels were analysed and compared between the two tasks. The t-test was usedfor statistical analysis. RESULT: In all nine subjects in group A and B, activation was observed in and adjacentto the left Broca's area. The mean number of activated pixels was 31.6 in group A and 27.8 in group B, adifference which was not statistically significant(P>0.1). Activities in and adjacent to the right Broca 's areawere seen in seven of group A and four of group B. The mean number of activated pixels was 14.9 in group A and 18in group B. Eight of nine volunteers in group A showed activity in the left primary motor area with negativecorrelation to the time-signal intensity curve. The mean number of activated pixels for this group was 17.5. Inthree volonteers, activation in the right primary motor area was also observed, the mean number of activatedpixels in these cases was 10.0.
CONCLUSION
During the rest period, functional MR imaging of the motor speechcenter combined with motor stimulation was more effective than that without stimulation, and simultaneouslyprovided mapping of the primary motor area.