A closed-loop stimulation technique developed by University of Freiburg researchers promises fewer side effects for patients with neurological disorders such as Parkinson's disease.

Open-loop stimulation, a therapy method currently used to treat Parkinson's disease, requires the implanting of an electrode in the patient’s brain; the electrode provides a continuous train of stimulation pulses.

The closed-loop approach developed at Bernstein Center Freiburg and BrainLinks-BrainTools cluster of excellence of Freiburg University uses an electrode stimulus that adjusts to momentary symptoms. Because the neuroprosthetic device records brain activity and constantly adapts its stimulation to current requirements, side effects such as gait imbalance or speech impairment may be avoided.

The controller continuously monitors the brain activity that reflects the severity of the Parkinson's disease symptoms. The nature of the recorded activity determines the stimulation signal. If stronger stimulation is required, the control input strengthens; if the activity becomes weaker, the stimulation decreases. If there is no pathological activity, the device will not provide any stimulation.

The same approach could also be used for the treatment of other brain diseases such as epilepsy or schizophrenia.