Relationship Between Ipsilesional Upper Extremity Motor Function and Corpus Callosum Integrity in Patients With Unilateral Stroke: A Diffusion Tensor Imaging Study

This study aims to investigate the relationship between ipsilesional upper extremity (UE) motor function and the integrity of the subregions of the corpus callosum in hemiparetic stroke patients with motor deficits of the dominant or non-dominant ipsilesional side. Twenty participants with unilateral UE deficits after stroke were included. Each of the 10 participants had lesions on the left and right sides. The ipsilesional UE function was assessed with the Jebsen-Taylor hand function test (JHFT), the 9-hole peg test (9HPT), and grip and pinch strength tests. Fractional anisotropy (FA) was calculated for the integrity of the 5 subregions of the corpus callosum. Pearson's correlation analysis was conducted to investigate the relationship between UE function and the integrity of the callosal subregions. The results of JHFT and 9HPT showed a significant correlation with the FA value of the corpus callosum I projecting to the frontal lobe in the left lesion group (p < 0.05). There was no correlation between the ipsilesional UE motor function and the FA value of the ulnar subregion in the right lesion group (p > 0.05). These results showed that the motor deficits of the ipsilesional UE correlated with the integrity of callosal fiber projection to the prefrontal area when the ipsilesional side was non-dominant.