Integration of electrical encephalography (EEG) and brain near-infrared spectroscopy (NIRS) to measure electrical activity, oxygenation and haemodynamic changes in human epilepsy
Epilepsy is the most common serious chronic neurological condition in children and is characterised by recurrent uncontrolled brain activity that is manifested by seizures. In up to 70% of patients seizures are controlled by medication, however for the remainder treatment options such as surgery or electrical stimulation may be an option. In this context, a better understanding of the spatial and temporal characteristics of epileptic events (i.e. where and when will they occur) is vital knowledge to developing strategies aiming to control seizures. Epileptic events are known to have complex relationships between neuronal electrical activity and the brain’s haemodynamic, oxygenation and metabolic changes; seizures can cause changes to metabolism and metabolic changes can underlie seizures. To achieve this aim there is a need for better real time in-vivo multimodal measurements of the brains electrical activity, oxygenation and haemodynamics, in humans having seizures. This is currently limited by instrumentation limitations, probe performance and availability of analysis methods.
The aim of this PhD project is to address this need through development of combined EEG and Near-Infrared Spectroscopy (EEG-NIRS) instrumentation, probes and analysis methods for data fusion; hence providing complementary information on brain activity and function. EEG allows the recording of the brains electrical activity with exquisite sensitivity by directly measuring local field potentials. NIRS is an optical measurement technique that uses low light levels; by estimating the degree of light attenuation at many wavelengths, one can estimate the concentration of the oxy- and deoxy- genated haemoglobin (HbO2, HHb).
This PhD project will be part of a collaboration between UCL Institute of Child Health and its partner Great Ormond Street Hospital (Life Sciences, Dr Carmichael, Prof. Cross) with UCL medical physics and biomedical engineering (Engineering, Dr Tachtsidis).
Clinical Neuroimaging: The combination of EEG and NIRS would allow us to monitor quantitatively the local haemodynamic, oxygenation and metabolic changes related to epileptic (and other electrical) events detected on EEG. In addition, will allow us to investigate how spontaneous oxygenation and haemodynamic changes are related to the EEG. The fusion of these two techniques will allow to monitor non-invasively and real-time neurovascular coupling and how is affected in epilepsy.
Image Analysis\ Acquisition\Reconstruction: New software tools are needed to allow us to integrate data from EEG-NIRS hence allowing enhanced interpretation of the relationships between oxygenation/haemodynamic changes and epileptic discharges to be determined. Understanding the relationship between brain electrical activity and brain tissue haemodynamics and oxygenation in both the temporal (time and frequency) and spatial domain (anatomical cortical registration), will allow better insights to neurovascular coupling in epilepsy.
Environment: This project involves scientists that between them are experts in EEG, optics and epilepsy, a multidisciplinary team of physicists, engineers and clinicians forming a new close collaboration between clinical and academic departments.