“There are currently only two methods to treat this disease. Either you can administer drugs or, if this does not work, one has to resort to electrical stimulation, the so-called deep brain stimulation (DBS). In the latter approach, also known as open-loop stimulation, an electrode is implanted in the patient’s brain to provide a continuous train of stimulation pulses,” the researcher explains. “In principle, this resembles the approach of the cardiac pacemaker.” However, the symptoms of Parkinson’s disease are not constant, therefore constantly stimulating the brain with the same signal is not the most efficient treatment.
“Our method provides a stimulus that adjusts itself to the symptoms. This means that we may be able to avoid some side effects such as gait imbalance or speech impairment which occur in conventional DBS treatment”, Vlachos explains. In this new closed-loop approach, brain activity is recorded and fed to a neuroprosthetic device, which then adjusts the stimulation strength. “Our controller continuously monitors the brain activity that reflects the severity of the PD symptoms. The nature of the recorded activity determines the stimulation signal. If you need stronger stimulation, the control input gets stronger, if the activity becomes weaker, the stimulation is weakened, and if there is no pathological activity the device will not provide any stimulation. This saves battery life as well and, hence, increases recharging and maintenance intervals – clearly an advantage for the patient carrying the battery.”
The same approach could be used for the treatment of other brain diseases such as epilepsy or schizophrenia. Moreover, Vlachos' method could also be used to devise controllers for non-invasive stimulation. “We can imagine treatment via transcranial stimulation techniques. In that case we could stimulate the brain from the outside, without the need to drill a hole into the skull and implant an electrode into the brain.” The closed-loop stimulation method developed by Vlachos and colleagues can further be adapted to influence brain activity to address basic science questions. “For instance, when animals attend to an input there is often an increase in oscillations. Using our controller, we can modulate the strength of oscillations and test if and how our attention is affected by such network oscillations.” After promising results in computer simulations modeling the activity dynamics of large networks of neurons, the next step will be to verify the approach in animal models, before it can be tested in human patients.
Original Publication:
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A new approach in stimulation could increase the life quality of patients with neurological disorders substantially. Copyright Gunnar Grah / BrainLinks-BrainTools
