EFFECTS OF STROKE LESION ON LANGUAGE PERFORMANCE AND WHITE MATTER CONNECTIVITY IN INDIVIDUALS WITH POST-STROKE APHASIA

Abstract

Lesion studies provide important source of information about brain structure and function in neurology and neuroscience. Historically the lesion-behavior studies could only be conducted post-mortem. In the last thirty years, the emergence of magnetic resonance techniques and advanced mathematical modeling algorithm made it possible to study brain structure and function in vivo. In the present study we examined the relationship between the characteristics of brain lesions and the language deficits in individuals with stroke-related aphasia. We also quantified the relationship between lesion extent and white matter connectivity in the left and right hemispheres, in relationship to language deficits. The results suggested that the lesion distribution in the left hemisphere frontal, temporal and parietal regions was associated with performance on language tests. In addition, white matter connectivity was affected by the stroke lesion more in the left than in the right hemisphere. However, the relationship of white matter connectivity with language scores showed the opposite effect. The integrity of the white matter tracts in the right hemisphere was related to better language scores, suggesting a possible compensatory role of the preserved right hemisphere white matter connections. Overall, our results suggest that the effect of stroke damage extends beyond lesion boundaries and can affect functioning of white matter pathways that connect the damaged cortical regions.