A Comparative Study of Single and Multiple Hand Tasks Using

ABSTRACT

PURPOSE: To assess, using functional MRI and by comparing activated motor sensory areas, the independence ofbrain activation during single and alternative multiple hand tasks. MATERIALS AND METHODS: The subjects were sixhealthy volunteers. Using at 1.5T Siemens system and single shot FID-EPI sequencing(T2* weighted image;TR/TE0.96msec/61msec, flip angle 90 degrees, matrix size 96X128, slice thickness/gap 5mm/0/8mm, FOV 200mm) and T1-weightedanatomic images, functional MRI was performed. The paradigm of motor tasks consisted of appositional fingermovements; the first involved the separate use of the right, left, and both hands, while an alternative taskinvolved the use of the right, left, and both hands in sequence. Using cross-correlation method(threshold0.6) andfMRI analysis software (Stimulate 5.0), functional images were obtained. The activated area of brain cortex, thenumber of pixel, the aberage percentage change in signal intensity, and correlation of the time-signal intensitycurve in the activated motor area were analysed and compared between the two task groups. Statistical analysisinvolved the use of Wilcoxon signed-rank test. RESULTS: It was seen on fMRI that durina both single andalternative motor tasks, the same areas were consistently activated; in four volunteers, most activation occurredin the contralateral primary motor area. Between the two task methods, the average change in the number ofactivated pixels was 12.3+/-5%, but the difference was not statistically significant(P>0.1). Increased signalintensity in the alternative task group(7.48+/-1.22%) was more statistically significant than in the single taskgroup(5.77+/-0.9%)(p<.001). With regard to the time-intensity curve, there was significant correlation between thetwo groups(0.87+/-0.07). CONCLUSION: Brain activation did not differ according to whether the motor task wassingle or alternative. We therefore suggest that during multiple stimuli, the relevant functional areas andneuronal column are activated independently.