Epilepsy affects just 1.2 percent of the US population, according to the Centers for Disease Control and Prevention (CDC), however the unpredictable seizures it causes are serious and must be managed using antiepileptic drugs. Now, research teams in the UK and France have developed an electronic device capable of detecting seizure activity and releasing a drug in response, which can be implanted into the brain.
The device could help stop seizures before they start and even help to prevent them in the future. The research team published the details of their device in the journal Science Advances.
According to the researchers, what makes this device different is the advanced soft and flexible electronics used in its design.
“These thin, organic films do minimal damage in the brain, and their electrical properties are well-suited for these types of applications,” said Professor George Malliaras, the Prince Philip Professor of Technology in Cambridge’s Department of Engineering, who led the research.
Seizure type and severity differ between patients, however most seizures occur when misfiring neurons start off a chain reaction in the brain which often results in loss of motor control and consciousness. Long-term antiepileptic drugs can help patients manage this disease, however it’s estimated that 30 percent of patients don’t respond to this treatment.
The device designed by Malliaras and his colleagues consists of a neural probe made up of an ion pump and electrodes to detect changes in neural activity. When the device detects seizure activity, it releases a neurotransmitter from the ion pump using electrophoresis. The amount of neurotransmitter released into the brain tissue can be customized based on the strength of the electric signal.
“In addition to be being able to control exactly when and how much drug is delivered, what is special about this approach is that the drugs come out of the device without any solvent,” said lead author Dr. Christopher Proctor, a postdoctoral researcher in the Department of Engineering. “This prevents damage to the surrounding tissue and allows the drugs to interact with the cells immediately outside the device.”
After implanting this device into the brains of mice, the research team found that the device could prevent seizures from happening using very small doses of the neurotransmitter. This is important because it means the device may not need to be refilled very often. And since the neurotransmitter eluted by the device is endogenous, side effects of the treatment are likely to be minimal and the neurons are capable of rapidly absorbing the drug.
Before the neural drug delivery device can be tested in human patients with epilepsy, the researchers must first study the long-term effects of implanting the device in animal models. The researchers are also establishing a prototyping facility at the University of Cambridge designed to build variants of the device which could be used to treat other neurological disorders such as Parkinson’s disease.