Cerebral, cerebellar, and hippocampal volumes were measured by quantitative magnetic resonance imaging on 112 children, ages 4-18 years, with epilepsy syndromes, determined by video-EEG telemetry, at Sydney Children’s Hospital, Randwick; St Vincent’s Hospital, Victoria; and New Children’s Hospital, Westmead, New South Wales, Australia. A significant reduction in cerebral (13%) and cerebellar (8%) volume was present in the epilepsy group compared with 44 controls. This included partial epilepsies such as frontal lobe epilepsy. Hippocampal asymmetry was more sensitive than volume reduction as a marker for mesial temporal lobe epilepsy. Volume reduction was independent of age of onset and duration of epilepsy, suggesting that brain volume reduction is present at the onset of epilepsy and is not the result of intractable seizures. IQ, was significantly correlated with cerebral and cerebellar volume, but not with duration or age of onset of epilepsy. 
COMMENT. While MRI data may not be reliable in localizing an epileptogenic area, measurements of brain volume reduction in partial epilepsies may prove of value in prognosis, especially in potential surgical cases. The correlation of IQ, with brain volume in the above MRI study of children with epilepsy corroborates similar findings in normal children and adolescents at Johns Hopkins University  and (Progress in Pediatric Neurology III. 1997;p294).
Mitochondrial complex I deficiency is reported in the hippocampal epileptic focus of patients with temporal lobe epilepsy . Mitochondrial dysfunction is a possible mechanism involved in the neuronal excitability in temporal lobe epilepsy.