Neural Substrate Responsible for Crossed Aphasia

Crossed aphasia (CA) refers to language impairment secondary to right hemisphere lesion. Imaging analysis on the lesion location of CA has not yet been reported in the literature. This study was proposed to analyze the most prevalent lesion site related to CA. Brain MRI of 7 stroke patients satisfying the criteria for CA were used to define Region of interest (ROIs) before overlaying the images to visualize the most overlapped area. Talairach coordinates for the most overlapped areas were converted to corresponding anatomical regions. Anatomical lesions where more than 3 patients' images were overlapped were considered significant. The overlayed ROIs of 7 patients revealed the lentiform nucleus as the most frequently involved area, overlapping in 6 patients. Our study first demonstrates the areas involved in CA by lesion mapping using brain MRI, and lentiform nucleus is the responsible neural substrate for crossed aphasia.