Pediatric frontal lobe epilepsy: white matter abnormalities and cognitive impairment

• Published in: Acta neurologica Scandinavica Vol. 129; no. 4; pp. 252 - 262
• Main Authors: Braakman, H. M. H., Vaessen, M. J., Jansen, J. F. A., Debeij-van Hall, M. H. J. A., de Louw, A., Hofman, P. A. M., Vles, J. S. H., Aldenkamp, A. P., Backes, W. H.
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01-04-2014; Hindawi Limited
• Subjects: Adolescent; Analysis of Variance; Anisotropy; Brain - pathology; Case-Control Studies; Child; Cognition Disorders - complications; Cognition Disorders - diagnosis; Cognition Disorders - etiology; Diffusion Magnetic Resonance Imaging; epilepsy; Epilepsy, Frontal Lobe - complications; Female; Humans; Leukoencephalopathies - complications; Male; Nerve Fibers, Myelinated - pathology; neuroimaging; Neuropsychological Tests; neuropsychology; pediatric neurology; Pediatrics; epilepsy; neuropsychology; pediatric neurology; neuroimaging
• ISSN: 0001-6314; 1600-0404
• DOI: 10.1111/ane.12183

Objectives
Cognitive impairment is frequent in children with frontal lobe epilepsy (FLE). Its etiology remains unknown. With diffusion tensor imaging, we have studied cerebral white matter properties and associations with cognitive functioning in children with FLE and healthy controls.
Methods
Thirty children aged 8–13 years with FLE of unknown cause and 39 healthy age‐matched controls underwent neuropsychological assessment, structural and diffusion‐weighted brain MRI. Patients were grouped as cognitively impaired or unimpaired, and their white matter diffusion properties were compared with the controls.
Results
Children with FLE had reduced apparent diffusion coefficients in various posteriorly located tract bundles, a reduced fractional anisotropy (FA) of the white matter tract between the right frontal and right occipital lobe, and smaller volumes of several collections of interlobar bundle tracts, compared with controls. The cognitively impaired patient group demonstrated significant increases in FA of the white matter of both occipital lobes, a reduced FA of white matter tract bundles between the right frontal and both left occipital lobe and subcortical white matter area, and smaller volumes of two collections of tract bundles connecting the frontal lobe with the temporal and parietal lobes, compared with controls.
Conclusions
Children with FLE had white matter abnormalities mainly in posterior brain regions, not confined to the area of the seizure focus. Cognitively impaired children with FLE showed the most pronounced white matter abnormalities. These possibly reflect disturbed maturation and might be part of the etiology of the cognitive impairment.