Vagus Nerve Stimulation: A Bioengineering Approach to Assess its Effects on Resetting the Epileptic Brain Dynamics

Project: Research project

Description

Epilepsy is the second most common neurological disorder to stroke and affects 1 % to 2% of the population worldwide. The Vagus Nerve Stimulation (VNS) is a recent, FDA approved, therapy for epilepsy. Although VNS is a form of neuromodulation, and a promising therapy for epilepsy and other neurological disorders (e.g. depression, bipolar disorder, anxiety), its mechanism of action on reducing the seizure frequency and severity in patients with refractory epilepsy remains unknown. Our research on the dynamical analysis of the scalp and depth EEG, in both animal models and human subjects with epilepsy, has shown that a) seizures are preceded by a pathological, progressive synchronization of nonfocal ("normal") brain sites with the epileptogenic focus long (average of 70 minutes) prior to a seizure onset, and b) this preictal synchronization is reversed postictally via what we have called resetting of the brain dynamics. In 2003, this line of research led to the development of the first prospective on-line real-time seizure prediction algorithm (Iasemidis and colleagues). Prediction paves the way to control. Seizure control experiments were initiated, first in biologically plausible computer models that exhibit "seizures", and subsequently in rodent models of epilepsy. These experiments pointed out to the same direction: pathological seizure precursors similar to the ones in human EEG were found in both the computer and animal models, intervention via timely electrical stimuli reset these precursors and reduced the probability of occurrence of seizures. Encouraged by these results, we herein propose a proof-of-concept study on seizure control in humans. We will seek to relate the successes and failures of the VNS treatment of patients to the VN S capability of resetting or not resetting the pathology in epileptic brain dynamics respectively. Our central hypothesis is that VNS would be a successful therapeutic modality for a patient if it resets the existing pathology of brain dynamics. We expect that a longitudinal dynamical analysis of the scalp EEG recorded from patients with implanted VNS devices will shed light on the investigation of this hypothesis. The EEG from patients at Barrow Neurological Institute will be monitored at regular visits over a period of 2 years after implantation of their VNS devices, that is the period over which successful VNS treatment achieves its most dramatic effect, slowly saturating thereafter. The participating physicians will be blinded to the results of the dynamical EEG analysis, thus avoiding any crossovers between this study and the medical care of the patients. This exploratory research is designed to provide preliminary data about the mechanism of VNS action on the basis of brain dynamics, the plasticity of VNS and brain's macroscopic electrical dynamics, and insights into improving VNS efficacy (e.g. by selection of electrical stimulation parameters that most effectively reset the pathological brain dynamics). The proposed research is an interdisciplinary investigation within the disciplines of bioengineering, neuroscience, neurology and neurosurgery towards the development of intelligent brain stimulators for epilepsy and other neurological disorders.
StatusFinished
Effective start/end date3/1/092/28/12

Funding

  • HHS: National Institutes of Health (NIH): $398,098.00

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Vagus Nerve Stimulation
Bioengineering
Seizures
Epilepsy
Brain
Electroencephalography
Nervous System Diseases
Scalp
Research
Computer Simulation
Animal Models
Pathology
Therapeutics
Equipment and Supplies
Neurosurgery
Neurology
Neurosciences
Bipolar Disorder
Cross-Over Studies
Electric Stimulation