Structural and functional imaging in children with partial epilepsy

Imaging plays an increasingly important role in the evaluation of children with complex partial seizures. Most partial epilepsy, especially of tempora l lobe origin, begins during childhood. Structural imaging with high-resolu tion MRI can help identify the etiology of partial seizure disorders in man y children. MRI studies also show the more widespread effect of seizures on brain structure. Progressive volume loss of the hippocampal formation in s ome patients with temporal lobe epilepsy provides evidence that continued s eizures may be associated with progressive neuronal injury. FDC-PET studies show regional decreases in glucose consumption in the cortical zone from w hich seizures arise. Functional abnormalities often are more extensive than the seizure focus. Studies in children with recent-onset epilepsy show tha t metabolic abnormalities are considerably less common than in adults with partial epilepsy, supporting the notion that in some patients there may be progressive metabolic changes that occur with continued seizures. Functiona l MRI may be used to identify language areas in children with partial epile psy. fMRI language tasks reliably identify the dominant hemisphere for lang uage dominance when compared to the intracarotid amytal procedure. Tests of verbal fluency and semantic decision identify frontal lobe language areas, while reading text paradigms and auditory passage paradigms are better for identifying temporal language areas. A panel of paradigms is best used to identify language areas in children being considered for epilepsy surgery. fMRI is a valuable tool for elucidating the impact of chronic neurologic di sease stales on the functional organization of language networks during dev elopment. Published 2000 Wiley-Liss, Inc.(dagger)