In this study, the conditions of human seizures are recreated in an animal model of temporal lobe epilepsy. The rodents used in this study are chemically induced to become chronically epileptic. Their Electroencephalogram (EEG) data is then recorded and analyzed to detect and predict seizures; with the ultimate goal being the control and complete suppression of seizures.
Two methods, the maximum Lyapunov exponent and the Generalized Partial Directed Coherence (GPDC), are applied on EEG data to extract meaningful information. Their effectiveness have been reported in the literature for the purpose of prediction of seizures and seizure focus localization. This study integrates these measures, through some modifications, to robustly detect seizures and separately find precursors to them and in consequence provide stimulation to the epileptic brain of rats in order to suppress seizures. Additionally open-loop stimulation with biphasic currents of various pairs of sites in differing lengths of time have helped us create control efficacy maps. While GPDC tells us about the possible location of the focus, control efficacy maps tells us how effective stimulating a certain pair of sites will be.
The results from computations performed on the data are presented and the feasibility of the control problem is discussed. The results show a new reliable means of seizure detection even in the presence of artifacts in the data. The seizure precursors provide a means of prediction, in the order of tens of minutes, prior to seizures. Closed loop stimulation experiments based on these precursors and control efficacy maps on the epileptic animals show a maximum reduction of seizure frequency by 24.26\% in one animal and reduction of length of seizures by 51.77\% in another. Thus, through this study it was shown that the implementation of the methods can ameliorate seizures in an epileptic patient. It is expected that the new knowledge and experimental techniques will provide a guide for future research in an effort to ultimately eliminate seizures in epileptic patients.
The neuromodulatory capabilities of ultrasound in tandem with electrical stimulation has a significant potential for development of neural interfaces to peripheral nerve.
The emerging field of neuroprosthetics is focused on the development of new therapeutic interventions that will be able to restore some lost neural function by selective electrical stimulation or by harnessing activity recorded from populations of neurons. As more and more patients benefit from these approaches, the interest in neural interfaces has grown significantly and a new generation of penetrating microelectrode arrays are providing unprecedented access to the neurons of the central nervous system (CNS). These microelectrodes have active tip dimensions that are similar in size to neurons and because they penetrate the nervous system, they provide selective access to these cells (within a few microns). However, the very long-term viability of chronically implanted microelectrodes and the capability of recording the same spiking activity over long time periods still remain to be established and confirmed in human studies. Here we review the main responses to acute implantation of microelectrode arrays, and emphasize that it will become essential to control the neural tissue damage induced by these intracortical microelectrodes in order to achieve the high clinical potentials accompanying this technology.
Intrauterine devices, or IUDs, are long-lasting forms of birth control that have effectiveness comparable to sterilization, while they can be removed at any time. However, the insertion process can be very painful, especially for individuals who have never given vaginal birth. The most common form of pain management for this procedure is having the patient take an ibuprofen an hour or so before the procedure, but this only helps with cramping afterwards, not the acute pain caused by insertion. Pain, and anxiety and fear regarding potential pain, serve as a barrier between users and this highly effective form of birth control. This report uses COMSOL to model lidocaine diffusion from 4% topical hydrogel into the cervix (the main site of acute pain during IUD insertion) over 180 minutes. The cervix was modeled axisymmetrically, using average experimental values for cervix size. Concentration at four specific probe points were measured over time and compared at different concentrations. A sensitivity analysis was performed by adjusting the diffusion coefficient of the epithelial layer. This model was developed to serve as a predictor for future drug applications across the cervix, to determine in advance whether a novel formulation of drug would be effective to significantly reduce pain. This model may be refined further with experimental values for the constants, and with further testing of different lidocaine concentrations.