Ictal cerebral haemodynamics of childhood epilepsy measured with near-infrared spectrophotometry

Near-infrared spectrophotometry (NIRS) is a new technique that allows continuous non-invasive monitoring of tissue oxygenation and haemodynamics in the brain. We used NIRS in various types of paediatric epileptic seizures in order to understand the pathophysiology of epileptic seizures in childhood epilepsy. This study examined 15 children ranging in age from 1.5 months to 16 years (nine males and six females), with different types of epilepsy. Six series of tonic spasms and 67 isolated seizures were recorded. The results demonstrated that several pathophysiological processes exist during epileptic seizures in childhood. (i) Convulsive seizures were associated with a remarkable increase in cerebral blood volume (CBV), while absence seizures were associated with a mild decrease or no change in CBV of the frontal cortex. (ii) An initial transient decrease in CBV was observed in some types of convulsive seizures. (iii) An ictal increase in CBV changed to an ictal decrease in the course of tonic status epilepticus. (iv) There was definite heterogeneity in the CBV changes during tonic spasms in patients with West syndrome. NIRS is easily applicable to paediatric patients with epilepsy and may provide new insights into the pathophysiology of various types of epileptic seizure.