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Unlabelled: Fever-induced refractory epileptic encephalopathy in school-age children (FIRES) is a recently described epileptic entity whose etiology remains unknown. Brain abnormalities shown by MRI are usually limited to mesial-temporal structures and do not account for the catastrophic neuropsychologic findings., Methods: We conducted FIRES studies in 8 patients, aged 6-13 y, using 18F-FDG PET to disclose eventual neocortical dysfunction. Voxel-based analyses of cerebral glucose metabolism were performed using statistical parametric mapping and an age-matched control group., Results: Group analysis revealed a widespread interictal hypometabolic network including the temporoparietal and orbitofrontal cortices bilaterally. The individual analyses in patients identified hypometabolic areas corresponding to the predominant electroencephalograph foci and neuropsychologic deficits involving language, behavior, and memory., Conclusion: Despite clinical heterogeneity, 18F-FDG PET reveals a common network dysfunction in patients with sequelae due to fever-induced refractory epileptic encephalopathy.

The development of functional brain asymmetry during childhood is confirmed by changes in cerebral blood flow measured at rest using dynamic single photon emission computed tomography. Between 1 and 3 years of age, the blood flow shows a right hemispheric predominance, mainly due to the activity in the posterior associative area. Asymmetry shifts to the left after 3 years. The subsequent time course of changes appear to follow the emergence of functions localized initially on the right, but later on the left hemisphere (i.e. visuospatial and later language abilities). These findings support the hypothesis that, in man, the right hemisphere develops its functions earlier than the left.

Clinical and electroencephalogram (EEG) observations permit a hypothesis for the pathophysiology of infantile spasms. The triggering area(s) for spasms is probably cortical. Diffuse hyperexcitability of the immature cortex and/or diffusion of the epileptic process from a focal abnormality would allow development of hypsarrhythmia. Cortical maturation from posterior to anterior might account for the location of causative focal abnormalities. In cryptogenic West syndrome, the predominant pathophysiologic process may be diffuse cortical hyperexcitability, explaining the severe developmental deterioration at the onset of spasms. In symptomatic West syndrome with focal pathology, the initial deterioration is often less striking, suggesting that the predominant effect is diffusion of the epileptic process. The pattern of eventual cognitive deficits follows a similar pattern.

An 8 year-old patient with a frontal lobe syndrome associated with epilepsy is reported. The neuropsychological evaluation showed that the behavioural problems resulted from moderate but specific disorders of the executive system. Evolution was favorable with complete disappearance of the neuropsychological difficulties when the seizures were controlled. This dysfunction, similar to that observed in adults, may occur in the first decade and be functional in origin.

Among 100 infants with infantile spasms studied before treatment, 14 had idiopathic spasms with a favourable outcome. They had a normal development, including reaching for objects before the age of 5 months and moderate regression without loss of eye following. Although it was hysarhythmic, the EEG tracing showed identifiable basic activity and sleep spindles; there was no slow waves focus even after diazepam administration and the spasms were "independent" even during a cluster. This type of infantile spasms seems to be a particular type of non-lesional epilepsy. It contrasts with idiopathic spasms of unfavourable outcome that apparently result from a preexisting and overlooked focal lesion responsible of later cognitive troubles.