Neurostimulation to improve level of consciousness in patients with epilepsy

• Authors: Abhijeet Gummadavelli, Yale University; Adam J. Kundishora, Yale University; Jon T. Willie, Emory University; John P. Andrews, Yale University; Jason L. Gerrard, Yale University; Dennis D. Spencer, Yale University; Hal Blumenfeld, Yale University
• Journal Title: Neurosurgical focus
• Volume: Volume 38, Number 6
• Publisher: American Association of Neurological Surgeons | 2015-06-01, Pages E10-E10
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3171/2015.3.FOCUS1535
• Subjects: Biology, Neuroscience; Health Sciences, Medicine and Surgery
• Keywords: Science & Technology; Life Sciences & Biomedicine; Clinical Neurology; Surgery; Neurosciences & Neurology; level of consciousness; arousal; epilepsy; deep brain stimulation; DBS; DEEP BRAIN-STIMULATION; CENTROMEDIAN THALAMIC NUCLEUS; CHRONIC ELECTRICAL-STIMULATION; PEDUNCULOPONTINE TEGMENTAL NUCLEUS; VENTROLATERAL PREOPTIC NUCLEUS; CHILDHOOD ABSENCE SEIZURES; TEMPORAL-LOBE EPILEPSY; SLEEP-WAKE CONTROL; BASAL FOREBRAIN; PARKINSONS-DISEASE

Abstract

When drug-resistant epilepsy is poorly localized or surgical resection is contraindicated, current neurostimulation strategies such as deep brain stimulation and vagal nerve stimulation can palliate the frequency or severity of seizures. However, despite medical and neuromodulatory therapy, a significant proportion of patients continue to experience disabling seizures that impair awareness, causing disability and risking injury or sudden unexplained death. We propose a novel strategy in which neuromodulation is used not only to reduce seizures but also to ameliorate impaired consciousness when the patient is in the ictal and postictal states. Improving or preventing alterations in level of consciousness may have an effect on morbidity (e.g., accidents, drownings, falls), risk for death, and quality of life. Recent studies may have elucidated underlying networks and mechanisms of impaired consciousness and yield potential novel targets for neuromodulation. The feasibility, benefits, and pitfalls of potential deep brain stimulation targets are illustrated in human and animal studies involving minimally conscious/vegetative states, movement disorders, depth of anesthesia, sleep-wake regulation, and epilepsy. We review evidence that viable therapeutic targets for impaired consciousness associated with seizures may be provided by key nodes of the consciousness system in the brainstem reticular activating system, hypothalamus, basal ganglia, thalamus, and basal forebrain.