Clinically indicated electrical stimulation strategies to treat patients with medically refractory epilepsy

• Published in: Epilepsia open Vol. 3; no. Suppl Suppl 2; pp. 198 - 209
• Main Authors: Izadi, Ali, Ondek, Katelynn, Schedlbauer, Amber, Keselman, Inna, Shahlaie, Kiarash, Gurkoff, Gene
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01-12-2018; John Wiley and Sons Inc
• Subjects: Convulsions & seizures; Critical Review; Deep brain stimulation; Drugs; Electrical stimulation; Epilepsy; FDA approval; Medial septal nucleus; Mortality; Nervous system; Quality of life; Supplement; Theta oscillations; United States > US; Electrical stimulation; Theta oscillations; Deep brain stimulation; Epilepsy; Medial septal nucleus
• ISSN: 2470-9239; 2470-9239
• DOI: 10.1002/epi4.12276

Summary
Focal epilepsies represent approximately half of all diagnoses, and more than one‐third of these patients are refractory to pharmacologic treatment. Although resection can result in seizure freedom, many patients do not meet surgical criteria, as seizures may be multifocal in origin or have a focus in an eloquent region of the brain. For these individuals, several U.S. Food and Drug Administration (FDA)–approved electrical stimulation paradigms serve as alternative options, including vagus nerve stimulation, responsive neurostimulation, and stimulation of the anterior nucleus of the thalamus. All of these are safe, flexible, and lead to progressive seizure control over time when used as an adjunctive therapy to antiepileptic drugs. Focal epilepsies frequently involve significant comorbidities such as cognitive decline. Similar to antiepilepsy medications and surgical resection, current stimulation targets and parameters have yet to address cognitive impairments directly, with patients reporting persistent comorbidities associated with focal epilepsy despite a significant reduction in the number of their seizures. Although low‐frequency theta oscillations of the septohippocampal network are critical for modulating cellular activity and, in turn, cognitive processing, the coordination of neural excitability is also imperative for preventing seizures. In this review, we summarize current FDA‐approved electrical stimulation paradigms and propose that theta oscillations of the medial septal nucleus represent a novel neuromodulation target for concurrent seizure reduction and cognitive improvement in epilepsy. Ultimately, further advancements in clinical neurostimulation strategies will allow for the efficient treatment of both seizures and comorbidities, thereby improving overall quality of life for patients with epilepsy.