A COMPARISON OF FUNCTIONAL MR ACTIVATION PATTERNS DURING SILENT AND AUDIBLE LANGUAGE TASKS

PURPOSE: To compare word generation tasks performed silently and aloud as paradigms for functional MR. METHODS: Images were obtained at 1.5 T, with echoplanar acquisition in nine subjects performing word genera tion aloud or silently. Functional images created from the echoplanar images by means of cross-correlation techniques were superimposed on a natomic reference images, The location of activation from the two task s was tabulated; the number of activated pixels in each region from th e two tasks was compared. RESULTS: Both silent and aloud word generati on produced activation in the inferior frontal lobes, sensorimotor cor tex regions, supplementary motor areas, and anterior cingulate gyri, p redominantly in the dominant hemisphere. Significantly more activated pixels and fewer artifacts were detected with silent word generation t han with word generation aloud. CONCLUSION: Word generation silently o r aloud produce activation in the brain. Greater activation can be det ected in the left frontal lobe with silent word generation, although t he subject's performance of the task cannot be monitored independently during silent word generation.