Vascular steal model of human temporal lobe epileptogenicity: the relationship between electrocorticographic interhemispheric propagation time and cerebral blood flow

Human temporal lobe epileptogenicity (i.e. seizure frequency) depends on epileptic and non-epileptic cerebral blood flow (CBF). Increasing non-epileptic cortical CBF is associated with reduction in epileptic cortical CBF. Seizure frequency increases logarithmically with non-epileptic cortical CBF increase and epileptic cortical CBF reduction. A model of human temporal robe epileptogenicity is derived from the mathematical equivalence to the logarithmic function of seizure frequency of (a) epileptic and non-epileptic CBF differential and (b) electrocorticographic (ECoG) interhemispheric propagation time (IHPT). The vascular steal model of human temporal lobe epileptogenicity suggests that a small CBF redistribution from non-epileptic to epileptic cortex should produce substantial reduction in temporal lobe seizure frequency in association with prolongation of IHPT. The equivalence of these CBF and ECoG parameters to the logarithmic function of seizure frequency suggests that the interhemispheric temporal lobe perfusion gradient and ECoG propagation time may be involved in the fundamental perturbation responsible for human temporal robe epileptogenicity. (C) 2000 Harcourt Publishers Ltd.