Deep Brain Stimulation: Neural Tissue Response and Analysis of Adverse Events

Abstract

Deep brain stimulation (DBS) is a common treatment for numerous neurological disorders, especially movement disorders, including, but not limited to, Parkinson's disease, essential tremor, and dystonia. Despite growing recognition, drastic shortcomings of DBS include infection, inflammation, hardware breaks, and extreme withdrawal syndrome. Brain-machine interfaces can be implemented only if the neural tissue response to electrodes and implants is understood and optimized. In this study, we analyzed adverse events resulting from DBS implantation. Through the past decade of DBS implant malfunctions, injuries, and deaths, it is apparent that high impedance and lead problems are major blockages. High impedance blocks the transmission of signals to the brain stimulator, deeming it useless. Leads are known to cause infection, especially along the incision site of implantable pulse generators (IPG). While the surgical technique depends on the skill of the surgeon, infections occur in a significant number of patients. Infection often means complete removal of the IPG, which could cause severe withdrawal syndrome; Parkinson's patients may experience severe motor symptoms such as akinesia or rigidity, dystonia patients can develop status dystonicus, epilepsy patients may experience an increase in seizures, and obsessivecompulsive disorder (OCD) patients may have worsening neuropsychiatric symptoms and suicidal ideation. In addition, studies have shown that quality-of-life scores after DBS are usually lower than preoperative scores, indicating that the long-term efficacy of DBS for treating these disorders may not be beneficial. However, recent studies on antimicrobial catheters may present an effective and inexpensive strategy against infection. As DBS is a relatively new technique, large, randomized clinical trials are still needed to provide necessary data to draw conclusions on long-term efficacy and safety, and device modifications may be needed to optimize the tissue response.