Visual rehabilitation training alters attentional networks in hemianopia: An fMRI study.

OBJECTIVE:Hemianopia is a visual field defect following post-chiasmatic damage. We now applied functional magnetic resonance imaging (fMRI) in hemianopic patients before and after visual rehabilitation training (VRT) to examine the impact of VRT on attentional function networks. METHODS:Seven chronic hemianopic patients with post- chiasmatic lesions carried out a VRT for five weeks under fixation control. Before vs. after intervention, we assessed the area of residual vision (ARV), contrast sensitivity function (CSF) and functional MRI data and correlated them with each other. RESULTS:VRT significantly improved the visual function of grating detection at the training location. Using fMRI, we found that the training led to a strengthening of connectivity between the right temporoparietal junction (rTPJ) to the insula and the anterior cingulate cortex (ACC), all of which belong to the cortical attentional network. However, no significant correlation between alterations of brain activity and improvements of either CSF or ARV was found. CONCLUSION:Visual rehabilitation training partially restored the deficient visual field sectors and could improve attentional network function in hemianopia. SIGNIFICANCE:Our MRI results highlight the role of attention and the rTPJ activation as one, but not the only, component of VRT in hemianopia.