Purpose: To investigate the brain areas related with the deficit in visuospatial attention in patients with traumatic brain injury (TBI) using functional MRI (fMRI).
Method: Twenty TBI and fifteen normal subjects were enrolled. The endogenous visuospatial attention task was used as an activation paradigm during fMRI. FMRI was performed on a 3T ISOL Forte scanner. Thirty slices were acquired using a single-shot EPI sequences (TR/TE=3000/ 30 ms, Flip angle 70 degrees, FOV=220 mm, 64x64 matrix, slice thickness 4 mm). The accuracy and reaction time to the attention task were measured during fMRI. Imaging data were analyzed using SPM-99 software.
Results: The ratio of accurate responses was lower (p<0.01) and the average reaction time was slower (p<0.01) in the TBI group than the normal group. The fMRI analysis showed more activation in the bilateral prefrontal cortices (the middle and inferior frontal gyri) and less activation in the cingulate gyrus, medial frontal lobe, bilateral temporo- occipital areas, and cerebellum in the TBI group compared with the normal group.
Conclusion: In TBI patients, impaired visuospatial attention might be resulted from the decreased activity of the cingulate, medial frontal, and temporo-occipital regions accompanied with compensatory hyperactivation of the prefrontal cortex.
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