Cerebral and Cerebellar Volume Reduction in Children with Intractable Epilepsy

Abstract

Summary:Purpme: Adult epilepsy studies have demonstrated cerebral and cerebellar volume reduction beyond the epileptogenic zone, correlating this with an inferior surgical outcome. We determined whether brain volumes were reduced in childhood epilepsy and the significance of this.Methods: Cerebral, cerebellar, and hippocampal volumes were measured by quantitative magnetic resonance imaging on 112 children (ages 4-18) with epilepsy syndrome determined by video-EEG telemetry. Eighty-seven had partial epilepsy and 25 had generalized epilepsy or indeterminate syndrome. Normative volumes were obtained from 44 child controls from the community.Results: A significant reduction in cerebral (12.6%) and cerebellar (7.9%) volume was present in the epilepsy group compared with controls. Analysis of subgroups revealed that cerebral volume was significantly decreased in frontal lobe and nonlocalized partial epilepsies. The mean hippocampal ratio of 0.73 for mesial temporal lobe epilepsy was significantly less than for all other syndromes and controls. There was no difference in the rate of hippocampal volume reduction between syndromes. There was a significant correlation between IQ and cerebral and cerebellar volume, but not duration or age of onset of epilepsy.Conclusions: Cerebral and cerebellar volume reduction is common in intractable epilepsy syndromes of childhood. These cross-sectional data suggest that brain volume reduction is present at epilepsy onset and is not a result of intractable seizures. Hippocampal asymmetry is more sensitive than volume reduction as a marker for mesial temporal lobe epilepsy, but neither measure is specific. Key Words: Cerebral-CerebellarEpilepsy-Reduction-Magnetic resonance imaging.Recent magnetic resonance imaging (MRI) studies have provided new insights into the question of loss of cerebral and cerebellar volume in patients with epilepsy. Quantitative MRI studies in adults with epilepsy have found loss of cerebral volume beyond the epileptogenic zone (1-3). Sisodiya et al. (1) demonstrated extrahippocampal volume loss in mesial temporal lobe epilepsy (MTLE) and correlated this with an inferior surgical outcome. Cerebellar atrophy is common in intractable epilepsy; the cause is still debated (4), but it has been correlated with a poorer surgical prognosis ( 5 ) and a lower threshold to drug side effects (6). Pediatric MRI studies have not addressed these issues. We aimed to determine whether cerebral and cerebellar volume reduction was evident in intractable childhood epilepsy syndromes, with potential significance for pathophysiology and treatment.

MR-based in vivo hippocampal volumetrics: 2. Findings in neuropsychiatric disorders

“…[36][37][38][39][40][41] Patients with mesial temporal lobe epilepsy exhibit smaller hippocampal volumes. 16,[42][43][44][45][46][47] This hippocampal volume reduction is highly concordant with the side of the epileptogenic focus, and hippocampal deficits are most pronounced ipsilateral to the epileptic focus. [48][49][50][51][52] If amygdala volume reductions are also documented, an additional gain in specificity of seizure lateralization is achieved.…”

“…109 Hippocampal volumetry data in temporal lobe epilepsy should be corrected for total brain volume, as this is the largest predictor of hippocampal volume. 110 112,113 showed that TBI patients had bilaterally smaller hippocampi compared to normal controls. In three cases of TBI acquired at birth, at age 4, and at age 9, 3D volumetric MRI revealed bilateral hippocampal volume reduction 13-15 years after the occurrence of TBI.…”

Morphologic and neurochemical alterations in the superior colliculus of the genetically epilepsy-prone hamster (GPG/Vall)

“…In particular, a reduction in the volume of the SC of the epileptic hamster has been observed compared to control animals. Decreases in volume have been associated with structural damage not only in animal models of AGS (Fuentes-Santamaria et al, 2005a), but also in different brain regions of patients having different types of epilepsies (Barr et al, 1997;Lawson et al, 2000;Bernasconi et al, 2001). The present findings also report a significant increase in the mean cross-sectional area of neurons located in the deep layers of the SC of the epileptic hamster compared to control animals which is consistent with alterations in presumptive output neurons projecting to Values expressed as nmol/mg wwt, are means and standard error.…”

Cognitive and Magnetic Resonance Volumetric Abnormalities in New-Onset Pediatric Epilepsy

“…In contrast, there are very few volumetric studies of children with epilepsy. Most studies to date have involved children with chronic epilepsy and the findings reveal abnormalities in cerebrum, cerebellum and hippocampus [70][71][72][73]74 . A recent voxel based morphometric investigation of children with chronic temporal lobe epilepsy reported a distributed pattern of abnormality in temporal and extratemporal lobe gray matter 75 , similar to that reported in the adults with temporal lobe epilepsy 76-81 .…”