Abstracts

Speed of propagation of seizures in temporal lobe epilepsy to the contra lateral temporal lobe is predictive of seizure outcomes. In humans direct seizure propogation from ipsilateral hippocampus to contra lateral hippocampus is believed to occur through neocortical parenchymal spread. Fast propagating seizures are associated with worse outcomes following temporal lobectomy.
The relationship between seizure propagation times in temporal lobe epilepsy and MRI volumetrics and neuropsychological function, however has not been examined. Propagation times from the ipsilateral to the contra lateral temporal lobe were measured using presurgical video telemetry. Propagation times were correlated with a comprehensive array of neuropsychological measures and quantitative MRI total brain grey and white matter volumes. Normalized Z-score measures were used for both neuropyschological testing and for MRI volumetrics. Analysis was performed on second seizure propagations by dividing groups into fast ([lt]5 seconds) and slow ([gt]5 seconds) propagators based on the median propagation times. 20 patients had 2nd seizure propagation times that could be analyzed. 9 had fast propagation times (2.3[underline]+[/underline]1.8 seconds) and 11 had slow propagation time (10.3[underline]+[/underline]5.4 seconds). Slow propagators had significantly better immediate (105.45[underline]+[/underline]14.4 vs. 89.44[underline]+[/underline]22) and delayed auditory memory (103.18[underline]+[/underline]12.3 vs. 89.22[underline] +[/underline]19.3). Similarly memory scores were also better for slow propagators (100.09[underline]+[/underline]16.6 vs. 86.56[underline]+[/underline]16.4). Fast propagators had greater total cerebral volumes compared to slow propagators. Segmentation by grey and white matter volumes were also larger for fast propagators compared to slow propagators These findings suggest that faster propagation of seizures to the contra lateral hemisphere is associated with worse neurophysilogical function and larger grey, white and total brain volumes.