Lateralization of cerebral blood flow in juvenile absence seizures

Abstract

Cerebrovascular blood flow in absence seizures and flow patterns during the ictal period have not been thoroughly investigated. We aimed to evaluate cerebral blood flow changes in typical juvenile absence seizures during the ictal and postictal phases. Seizures were recorded in three patients (mean age: 21 +/- 1 years) with multiple daily typical absence seizures. Simultaneous video electroencephalography and bilateral middle cerebral artery transcranial Doppler ultrasonography recordings were conducted during seizures. Basal, ictal, and postictal blood flow velocities were recorded bilaterally, and offline analyses were performed in relation with generalized spike and wave discharges. Total of 43 seizures were recorded. Ictal increase and postictal decrease of cerebral blood flow velocities were significant for both sides (P < 0.001). The interhemispheric asymmetry in the ictal velocity increase was significant (P < 0.05). The interhemispheric asymmetry in the postictal velocity decrease was not significant (P > 0.05). The blood flow velocity increase after seizure onset indicates a vascular coupling mechanism. A sudden and then a gradual decrease in blood flow velocity, which lasted even after the seizure ceased, might suggest a preventive mechanism to avoid excessive seizure duration or even an absence status epilepticus. Significant asymmetries in increase and a symmetrical decrease may support the cortical focus theory.

Vascular topology and blood flow are acutely impacted by experimental febrile status epilepticus

“…While no studies exist on vascular lateralization there is some support for lateralization of blood flow in seizures, with increases during ictal discharges and decreased blood flow after seizure cessation that was asymmetric between hemispheres. 37 We recently reported similar asymmetric differences in MRI T2 signal and CBF in a preliminary study of FSE patients that underwent MRI evaluations within 6 hrs of SE onset. 38 CBF has been also shown to lateralize with pathology in newborns with focal seizures.…”

Vascular topology is acutely impacted by experimental febrile status epilepticus

“…When lateralization was performed FSE pups had a 2% reduction in vessel density (high vs. low) that was significant whilst controls had a 1.6% change that was trending. While no studies exist on vascular lateralization there is some support for lateralization of blood flow in seizures, with increases during ictal discharges and decreased blood flow after seizure cessation that was asymmetric between hemispheres 33 . We recently reported similar asymmetric differences in MRI T2 signal and cerebral blood flow in a preliminary study of FSE patients that underwent MRI evaluations within 6 hrs of SE onset 34 .…”

Patterns of postictal cerebral perfusion in idiopathic generalized epilepsy: a multi-delay multi-parametric arterial spin labelling perfusion MRI study

“…In addition to the global increase, a focal increase in thalamic blood flow of 3.9 to 7.8% following hyperventilation-induced typical absences with GSW discharges was noted 21 . Measurements of CBF using transcranial Doppler ultrasonography in absence seizures 26 and SPECT in IGE 22 and childhood absence epilepsy 23 24 revealed ictal increase and postictal decrease. Conversely, a SPECT study reported that CBF is diffusely reduced throughout the brain during the occurrence of typical absence seizure, whereas CBF increases during the postictal phase 27 .…”