Epileptic seizures have mystified people for thousands of years, striking their victims at random times and without any warning. Yet, the brain doesn’t simply enter this violent state without a moment’s notice, but actually brews the electrical storm until it manifests itself outwardly. Knowing about oncoming seizures by monitoring this developing brain activity would help epileptic people take preemptive action and hopefully lessen the impact of any seizures.
A company called NeuroVista (Seattle, WA) has been working on an implant that is proving itself capable of monitoring the brain and helping to predict oncoming seizures with impressive accuracy. The implant itself is not new, having been developed a few years ago to be able to collect long term EEG data directly from the surface of the brain. The latest development is the coupling of the NeuroVista implant with another implant placed like a cardiac pacemaker under the chest, that transmits data from the brain implant to a hand-held device that displays warnings about oncoming seizures. A two year study following 15 people implanted with the system in Australia has shown that with proper programming of the devices to analyze brain activity data, effective seizure prediction can be made practical and quiite precise.
From the study abstract:
We implanted 15 patients with the advisory system. 11 device-related adverse events were noted within four months of implantation, two of which were serious (device migration, seroma); an additional two serious adverse events occurred during the first year after implantation (device-related infection, device site reaction), but were resolved without further complication. The device met enabling criteria in 11 patients upon completion of the data collection phase, with high likelihood performance estimate sensitivities ranging from 65% to 100%. Three patients’ algorithms did not meet performance criteria and one patient required device removal because of an adverse event before sufficient training data were acquired. We detected no significant changes in clinical effectiveness measures between baseline and 4 months after implantation.
This study showed that intracranial electroencephalographic monitoring is feasible in ambulatory patients with drug-resistant epilepsy. If these findings are replicated in larger, longer studies, accurate definition of preictal electrical activity might improve understanding of seizure generation and eventually lead to new management strategies.