Many diseases, including neurological ones, cannot be cured as yet, and sometimes medication doesn’t help. Fortunately, there is good news with other treatments, like stimulating cranial nerves. Professor Kristl Vonck explains how it’s possible to treat epilepsy, depression and perhaps even corona using neurostimulation.
The wandering nerve
Professor Vonck and her colleagues (Faculty of Medicine and Health Sciences) are researching the stimulation of the so-called ‘wandering’ nerve, or the vagus nerve. Every human has twelve pairs of cranial nerves, or cranial nerves, that transmit both motor and sensory information between the brain, neck and body. The wandering nerve is the tenth pair of these.
The fact that the wandering nerve is suitable for treating certain conditions has to do with where it is located in the body. Kristl: “Due to its branched, cable-like structure, the wandering nerve connects many things. They are a very special pair, as they also relate to complex functions such as flavour detection. In addition, the nerve runs very deep inside the body and also goes to the heart and other organs. On top of that, the nerve can help the body relax after periods of stress.”
With neurological disorders, chemical intervention using drugs often does not help the patient. Our brains are very complex. They not only work with chemical structures, but also with complex nerve pathways. The treatment of stimulating the wandering nerve with electricity is so effective that it was recognized years ago for diseases such as epilepsy. Yet there are still a lot of uncertainties. Kristl: “There is a lot of activity running through that wandering nerve. In some neurological diseases this activity is disturbed. Using electricity we can deliver artificial stimuli and thus influence this disruption. We do this with a kind of pacemaker that we place surgically in the neck. We can make people better with this treatment, but not bring about a cure. The electrical stimuli in our brains are much more complex than the stimuli that we can imitate. There are still a great number of open questions that need to be answered through our research.”
Everyone is unique
Moreover, everybody is different. This means that no brain network is the same. That’s why everyone reacts differently to the stimulation. Many different combinations are possible to stimulate the brain. It’s why we vary the strength, frequency and pulse width of the stimuli. Kristl: “We want to find out what the optimal neurostimulation is, and that varies widely from patient to patient. Together with a company, we have developed devices that we don’t need to put in the body, but that can stimulate the nerve externally in a non-invasive way. We also need to investigate that further: can we achieve the same as with an implant?”
Nipping depression in the bud
The stimulation of the wandering nerve has proven effective not only as a treatment for epilepsy, but also for depression. This makes more sense than you would think, as there is a clear link between the two diseases. Just as for patients with other neurological conditions, epilepsy patients also sometimes suffer from depression. During the treatment of their epilepsy, their depression appears to improve in certain cases. How does that work? Well it’s because both diseases manifest themselves in the same brain network, and the wandering nerve is connected to certain parts of that network. This treatment has now been recognized, but still requires a lot of additional research. “This research is more important today than ever,” says Kristl. “All over the world, pharmaceutical companies and academics are looking for a vaccine to nip Covid-19 in the bud. But the seeds for depression have already been sown. A tsunami of depression awaits us. We have to prepare for that too. This research can be another tool to treat the problem, no matter how small.”
Fighting inflammatory diseases?
But there’s more. It seems that this nerve stimulation is not only able to treat neurological diseases, but also inflammatory diseases such as rheumatoid arthritis. In a healthy body, the wandering nerve detects inflammatory responses very quickly, thus telling the brain to initiate action to resolve the inflammation. Kristl: “If that response is disturbed, as is the case with inflammatory diseases, you can initiate a similar effect through stimulation. We are seeing quite good results with this sort of treatment. A number of studies are also currently underway among corona patients with inflammatory reactions. Because we have these external devices available, this is easily achievable. But the scientific question is very difficult to solve. These people also receive other treatments at the same time, so we don’t know exactly what it is that is making them better.”