Structural connectivity of the frontal lobe in children with drug-resistant partial epilepsy

The superior longitudinal fasciculus (SLF) II and cingulum are two white matter tracts important for attention and other frontal lobe functions. These functions are often disturbed in children with drug-resistant (DR) partial epilepsy, even when no abnormalities are seen on conventional MRI. We set out to determine whether abnormalities in these structures might be depicted on diffusion tensor imaging (DTI) studies in the absence of abnormalities on conventional MRI. We compared the DTI findings of 12 children with DR partial epilepsy with those of 12 age- and gender-matched controls. We found that the SLF II fractional anisotropy (FA) values of the patients were significantly lower than those of the controls (means: 0.398 ± 0.057 and 0.443 ± 0.059, respectively, P = 0.002). Similarly, apparent diffusion coefficient (ADC) and parallel diffusivity values for SLF II were also significantly lower in the patients. There were no differences in the FA and ADC values of the cingulum. Our findings are consistent with abnormal structural connectivity of the frontal lobe in children with DR partial epilepsy and provide a possible explanation for the previously reported functional abnormalities related to the SLF II in these patients.

Research Highlights
► Studied 12 drug-resistant partial epilepsy children (normal frontal lobe 3 T MRIs).
► They were compared with 12 matched healthy controls.
► Patients had significantly lower SLFII FA, ADC and parallel diffusivity.
► No differences were found in cingulum FA and ADC.
► First study to report SLFII DTI abnormalities in pediatric partial epilepsy.