Hippocampal Stimulation in the Treatment of Epilepsy
Section snippets
The problem of mesial temporal lobe epilepsy
Despite an armamentarium of at least 20 different antiepileptic drugs (AEDs), approximately 30% of patients with epilepsy remain refractory to all forms of pharmacotherapy. One of the commonest forms of medically intractable epilepsy is mesial temporal lobe epilepsy (MTLE). Based on a randomized controlled trial by Wiebe and colleagues,12 clinical practice guidelines were generated that recommend that these patients undergo evaluation for brain surgery, usually anteromesial temporal lobe
Mechanisms of EBS in epilepsy
The exact mechanism of action of EBS in epilepsy is not known. However, current evidence supports a neuromodulatory effect on cortical excitability that disrupts seizure generation either directly, or indirectly through subcortical neuronal circuits.17 At a mechanistic level, the antiseizure effect of EBS is supported by at least 19 in vitro and in vivo studies in epilepsy models using direct current (DC) or single pulse stimulation,18, 19, 20, 21, 22, 23, 24, 25 low-frequency stimulation,26, 27
Discussion
Like other forms of electrical neuromodulation, HS for mesial MTLE holds the promise of an intervention that is nonresective, minimally invasive, dose adjustable, largely reversible, and presumably safe. However, closer analysis of electrical stimulation of the brain for epilepsy reveals how little is known about this intervention, and how tenuous are the bases for this promise. For example, although the intervention is not evidently resective and it is clearly less invasive than standard
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This work was supported by the Hopewell Professorship of Clinical Neurosciences Research, Hotchkiss Brain Institute, University of Calgary.
The authors have nothing to disclose.