Researchers suggest that both symptom severity and the clinical outcomes achieved through deep brain stimulation could be linked to a specific pattern of brain activity, which is found in patients with isolated dystonia.

In these patients, oscillatory brain activity in enhanced in the “theta band”—rhythmic neural activity that occurs at a frequency of between 4 and 12 Hertz, according to the research team from the Movement Disorders Unit of Charité – Universitätsmedizin Berlin Department of Neurology, led by Prof Dr Andrea Kühn, of Charité’s Department of Neurology.

The study, published recently in the Annals of Neurology, included 27 patients. Using stereotactic brain mapping technology, these patients received bilateral DBS electrodes implanted into their globus pallidus internus (GPi), a region within the basal ganglia.

All of the patients studied exhibited the typical interplay between brain activity, previously determined symptom severity, proximity to the optimal stimulation target, and clinical outcomes, explains a media release from Charité – Universitätsmedizin Berlin.

Using “LEAD-DBS,” a type of software initially developed at Charité, the researchers used these data to reconstruct a 3D map of the oscillatory amplitudes within a virtual brain. This revealed a significant localized increase in the relevant activity pattern, which was found in the area of the brain associated with the best treatment outcomes in dystonia patients undergoing DBS.

“Our findings suggest that theta band oscillations may be responsible for dystonic symptoms, and may also explain the mechanism of action of DBS, as well as the location of the optimal stimulation target in affected patients,” explains Dr Wolf-Julian Neumann of the Movement Disorders Unit, in the release.

“We are also currently studying the long-term effects of DBS on neuronal activity. We are one of a few centers in the world to do so, and are currently running a separate study involving 15 patients with dystonia. Our research is made possible thanks to an innovative DBS system, which continues to record brain activity after implantation,” adds Kühn, Head of the Movement Disorders Unit and Member of the Board of Directors of the NeuroCure Cluster of Excellence.

[Source(s): Charité – Universitätsmedizin Berlin, Science Daily]