Development of simultaneous electroencephalography and near-infrared optical topography for applications to neurovascular coupling and neonatal seizures

• Main Author: Cooper, R. J.
• Published: University College London (University of London) 2010
• Subjects: 610
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.565120

This thesis describes the development and preliminary application of methods for performing simultaneous electroencephalography (EEG) and near-infrared (NIR) imaging of the brain. The simultaneous application of EEG and NIR imaging has many benefits because of the complementary nature of the two modalities, and has significant potential in the study of the relationship between neuronal activity and cerebral haemodynamics. This work goes beyond previous experiments which have combined EEG and limited-channel near-infrared spectroscopy by designing and implementing an arrangement which allows dense near-infrared optical topography and EEG to be performed over the same cortical area, with as simple an application method as possible. These application methods are described in detail, as is their extensive testing using novel dual-modality phantoms and an in-vivo EEG-NIR imaging experiment in a healthy adult. These methods are subsequently applied to the study of neonates in the clinical environment. An intricate EEG-NIR imaging experiment is designed and implemented in an investigation of functional activation in the healthy neonatal visual cortex. This series of experiments also acts as a further test of the suitability of our EEG-NIR imaging methods for clinical application. The results of these experiments are presented. The EEG-NIR imaging arrangement is then applied to four neurologically damaged infants in the neonatal intensive care unit, each of whom had been diagnosed with seizures. The results of these studies are presented, and a potentially significant haemodynamic feature, which is not present in agematched controls, is identified. The importance and physiological implications of our findings are discussed, as is the suitability of a combined EEG and NIR imaging approach to the study and monitoring of neonatal brain injury.