Stimulating the brain

A small medical device may hold the future to improving the lives of people with neurological disorders such as Parkinson’s disease.

The device is the result of a joint collaboration between the NRC Institute for Integrated Manufacturing Technologies (NRC-IMTI), the Lawson Health Research Institute (part of the London Health Sciences Centre Research) and Medtrode.

It is designed to help support a relatively new procedure called Deep Brain Stimulation (DBS) which has emerged as one of the recommended treatments for advanced cases of movement disorders, associated with neurological diseases.

With DBS, an electrode is surgically implanted in the brain. The electrode is used to create an electrical impulse, which cancels out abnormal nerve signals that are responsible for symptoms such as tremors. A pacemaker-like device, implanted near the collarbone, is used to generate the electrical signal.

Use of DBS with patients suffering from Parkinson’s has proven to be effective in treating the debilitating symptoms of tremors, slowness of movement and rigidity.

Reduced size is one of the striking features of the new device, known as a neurological probe. For example, the size of the electrode has been reduced to the thickness of a push pin, 0.5 mm, down from an electrode closer in size to a piece of speaker wire. The smaller size reduces the impact of the procedure on the patient.

The new device is also unique in that it is capable of both stimulating the brain, but also recording electrical impulses created by the brain. Dr. Mandar Jog, co-inventor and neurologist at Lawson Health Research Institute, notes that the current procedure is very demanding on patients. For example, neurologists require time to first locate the appropriate area for the electrodes, must record signals present in this location and, only later, actually implant to electrode that will actually send the signals and control the symptoms.

“The traditional surgical approach is to identify the regions of the brain involved with the movement disorder on the basis of laborious physiological studies performed in the operating room over several hours,” he notes. Currently this surgical procedure is performed with the patient awake in a cumbersome head frame and lasts 6-8 hours. Dr. Jog also describes the process as “imprecise”. He notes that the designated recording period doesn’t always capture the full range and extent of signals.

The prototype device produced by the team integrates the recording and stimulating function with multiple channels available for each function, on a much smaller and less traumatic device. Recording could be used intra-operatively if desired, but the emphasis would be on allowing the stimulation field to be configured with chronic recordings to save operating room time, tailor the simulation fields and thereby reduce side effects.

The partnership has relied on expertise from NRC-IMTI in the field of miniaturization and the use of lasers for micromachining and processing of materials. The project has also entailed challenges finding materials that are both machinable but also biocompatible.

Dr. Suwas Nikumb, co-inventor and leader of the Precision Fabrication Processes Group at NRC-IMTI says, “through this partnership we can use the expertise in manufacturing science available at NRC-IMTI to build a device that has more channels and functions and yet is much smaller than current electrodes.”

Private-sector partner, Medtrode, is also involved to help ensure effective transfer of the technology from the lab to the marketplace. The current market for neurostimulation procedures is worth $25-$35 million and is estimated to rise to $100 million in the next five years.

The development of the neurosurgical electrode was funded in part by a Canadian Institutes of Health Research (CIHR) Proof of Principle (POP) Phase I grant which supports research designed to establish proof of principle of an invention or discovery. A CIHR POP Phase II grant fund, matched by funding by Medtrode, will help move the discovery to a further stage in the innovation cycle and build on the success of the Phase I grant.