A widening range of neurological conditions can now be treated using electrical stimulation of targeted areas of the brain. However, even if the idea of having someone drill through your skull to implant the electrodes doesn't put you off, the not-inconsiderable risk of infection might. So the announcement of a technology that avoids such invasive processes could be great news for people with conditions as diverse as Parkinson's disease, epilepsy, and depression.
Stentrodes are electrodes made from thin platinum wires that form an open cylinder 4 millimeters (0.16 inches) across. Inserted into blood vessels, they allow the blood to flow through them, but can deliver electrical pulses that pass through the vessel walls and affect nearby organs.
Dr Nick Opie of the University of Melbourne hopes that by inserting them into blood vessels in the neck and pushing them along the vein to the desired brain region it will be possible to get the benefits of deep brain stimulation without most of the risks and pain.
In Nature Biomedical Engineering, Opie describes the success of trials of the technology on eight sheep. Using a telemetry unit connected to an external source of power, Opie was able to trigger responses in the sheep's brains that caused visible movements of the limbs and facial muscles.
Changing the facial expressions of sheep may be a niche currently restricted to Aardman Animations, but Opie and colleagues are planning human trials. The next stage, which Opie told IFLScience his team are hoping to begin next year, will be to insert stentrodes to record brain signals, something they have previously demonstrated in animal models. These recordings can alert people with epilepsy prior to seizures, giving them a chance to get themselves to a safe location. “Stimulation will be a few years after that,” Opie said.
Having stentrodes available for use outside clinical trials is an even longer-term prospect, but Opie is hopeful that once approval is received adoption will be rapid. The use of stents to keep blood vessels open is widespread, and doctors are practiced in inserting them into easily accessible parts of the body and controlling their movements to reach the required location. “We wanted a procedure clinicians are already familiar with,” Opie told IFLScience.
Meanwhile, Deep Brain Stimulation has become sufficiently widespread that doctors have learned a lot about the optimum signals to control the symptoms of neurodegenerative diseases.
Opie hopes the combination of capacities to read the brain's signals and provide stimulation could be used to send countering pulses that interrupt incipient epileptic seizures. Likewise, it may become possible to ensure that messages from one part of the brain reach the place they need to go when disease or damage interrupts natural transmission.