Photo Credit: Artemis Diana
Deep brain stimulation offers advantages such as adjustability, reversibility, and the potential for rapid and long-term improvement in tardive dyskinesia.
Recent research supports the use of deep brain stimulation (DBS) as an established treatment option when pharmacological therapy alone does not provide sufficient relief for patients with tardive dyskinesia (TD). The Journal of Clinical Medicine published these findings online.
“DBS has been successfully used to treat several movement disorders, including Parkinson’s disease and dystonia,” wrote study authors. “More recently, DBS has also been used to treat patients with TD and OCD, especially in drug-resistant forms.”
According to the study, TD can occur during and after the use of neuroleptics. The prevalence of TD is estimated at 0.4% to 9% in patients receiving antipsychotics; however, some studies indicate a more frequent occurrence (20%–50%). Interestingly, when antipsychotic-induced TD follows exposure to neuroleptics for at least three months—one month among individuals aged 60 years and older—and persists for at least one month after the last dose of the drug, then TD can be diagnosed.
“Aside from pharmacological interventions (changing the dose or the drug) or implementing TD-targeted treatment, there is a promising method that may offer new opportunities for this group of patients—[DBS],” the authors wrote. “This method enables rapid and, more importantly, long-term improvement in motor function and quality of life (QOL) in patients with TD.”
Currently, the Abnormal Involuntary Movement Scale is commonly used to assess TD. The Burke-Fahn-Marsden Dystonia Rating Scale, which consists of movement and disability subscales, is also used to measure TD.
“The pharmacological treatment of TD is challenging; conventionally administered pharmacotherapies are only beneficial at the initial stage, and the available data point to a lack of satisfactory outcomes in long-term use,” the authors stressed.
The study authors explained that DBS offers advantages such as adjustability, reversibility, the potential for rapid and long-term improvement, and the ability to perform bilateral stimulation in a single surgical session.
Studies suggest that DBS is safe and minimally invasive, with few severe complications during follow-up. However, it necessitates continuous follow-up for parameter optimization and carries the risk of hardware complications like electrode displacement and battery depletion.
“The primary criterion for inclusion in DBS is a high severity of symptoms that significantly impede function and have lasted for more than a year, with no satisfactory response to pharmacological treatment with clozapine or tetrabenazine for at least four weeks at the highest doses tolerated by the patient,” they wrote.
Patient selection for DBS is crucial, considering factors like symptom severity, duration, and response to pharmacological treatments. Proper electrode placement and programming are essential for optimizing clinical outcomes. Although surgical techniques evolved to minimize inaccuracies, adjustments in programming often are necessary to address suboptimal electrode placement or displacement. Understanding the temporal sequence of symptom responses to stimulation aids in effective programming.
Research primarily focuses on stimulating brain areas like the internal globus pallidus (GPi) and subthalamic nucleus, which are part of the motor circuits implicated in movement disorders. GPi DBS targets specific regions associated with motor, limbic, and prefrontal functions. Stereotactic techniques aid in precise electrode placement, typically within specific coordinates relative to anatomical landmarks.
Stimulation parameters, including voltage, frequency, and pulse width, are adjusted based on individual responses. While monopolar stimulation is common, some studies explore bipolar modes. Continuous research aims to refine DBS techniques and improve guidelines for optimal patient outcomes.
“The latest technical achievements in the field of construction of stimulators and electrodes—such as modeling the shape of the impact field—as well as the results of new studies focused on the paths connecting the gray matter of various brain regions allow us to expect discoveries in research using DBS, hopefully also in TD,” concluded the authors.
