Smart implants may alleviate neurological conditions

SMART implants in the brains of people with neurological disorders could eventually help develop treatments for people with Parkinson's disease, depression and obsessive compulsive disorder.

Last week, a team from Medtronic of Minneapolis, Minnesota, reported on their design for a neurostimulator at the Engineering in Medicine and Biology Society meeting in Minneapolis. The devices use electrodes to deliver deep stimulation to specific parts of the brain.

Neurostimulators are already approved to treat conditions such as Parkinson's disease, essential tremor, and dystonia, as well as obsessive compulsive disorder. But existing devices deliver stimulation on a set schedule, not in response to abnormal brain activity. The Medtronic researchers think a device that reacts to brain signals could be more effective, plus the battery would last longer, an important consideration for implantable devices.

Tim Denison, a Medtronic engineer working on the device, says that the neurostimulator will initially be useful for studying brain signals as patients go about their day. Eventually, the data collected will show whether the sensors would be useful for detecting and preventing attacks.

Human trials are years away, but elsewhere, NeuroPace a start-up firm in Mountain View, California, is finishing clinical trials using its RNS smart implant device in 240 people with epilepsy, the results of which will be available in December, says Martha Morrell, chief medical officer at NeuroPace. An earlier feasibility study on 65 patients provided preliminary evidence that the devices did reduce seizures.

The NeuroPace device is implanted within the skull where it monitors electrical activity via electrodes implanted deep in the brain. If it spots the "signature" of a seizure, it will deliver brief and mild electrical stimulation to suppress it. Mark George, a neurologist at the Medical University of South Carolina in Charleston, says heart pacemakers developed in a similar way, as researchers learned to make them detect and react to signals from the heart. "I think it's absolutely inevitable that we'll develop a smarter, more intelligent way to figure out how and when to stimulate," George says.