Recommended Citation
Babbs, Charles F., "Feasibility of EEG based detection of ischemic stroke: studies in a simple computational model" (2024). Weldon School of Biomedical Engineering Faculty Working Papers. Paper 35.
https://docs.lib.purdue.edu/bmewp/35
Date of this Version
6-25-2024
Keywords
Action potential, Ambulances, Diagnosis, Dipole, Early intervention, Electroencephalography, Hypoxia, Morbidity, Neuron, Paramedic, Point-of-care systems, Pre-hospital diagnosis, Rapid, Reperfusion, Thrombolysis, Time to treatment, TPA, Telemedicine
Abstract
Objective: To explore quantitatively, using streamlined mathematics, how transmembrane potential differences across cell bodies of individual cortical neurons could act to produce the skin surface potentials of the electroencephalogram (EEG), and how ischemic stroke might be detected using EEGs in prehospital settings. Methods: From fundamental principles of electrostatics, anatomy, and physiology, one can characterize the strength of apparent dipoles created during activation of the cell bodies of individual cortical neurons. The transient dipole strength in a cortical neuron depends upon the size and surface area of its cell body, its capacitance, and the difference in transmembrane electrical potentials appearing across the cell body. The aggregate potentials of the EEG are a function of the many individual dipole strengths, directions, and distances from the electrode. Reduced activity and firing rates of cortical neurons model the effects of acute ischemia in tissue underlying one or both EEG electrodes. Results: Clinically realistic EEG records can be simulated if 25 cell bodies are randomly active in the 1 cm3 volumes of gray matter closest to skin surface electrodes at any instant in time. Complete cessation of neural activity under just one EEG electrode causes a modest decrease in aggregate EEG signal amplitude and frequency. However, reduction in neural activity to between 5 and 50 percent of normal under both EEG electrodes causes detectable 30% to 70% decreases in EEG amplitude, compared to normal. Conclusions: Such changes in electrical activity could be used in scenarios for rapid early detection of acute ischemic stroke, possibly expediting thrombolytic or reperfusion therapy, provided that both electrodes are located over the ischemic area and that the signals are compared to normal signals from the opposite side of the head.