Study Rationale:
Dysphagia -- difficulty swallowing -- is common in people with advanced Parkinson's disease (PD). Dysphagia often leads to aspiration -- inhaling of food -- which can result in pneumonia, a leading cause of death in people with advanced PD. These complications substantially worsen health-related quality of life, aggravate the disease and lead to death. Standard treatments, such as medications for motor symptoms and deep brain stimulation, often fall short of improving dysphagia. A likely reason for the failure of the standard deep brain stimulation is that it targets the part of the brain that does not control swallowing. For this reason, stimulating this brain region, called the subthalamic nucleus (STN), is unlikely to resolve swallowing problems. However, stimulation of another brain region -- the substantia nigra pars reticulata (SNr) -- has a therapeutic potential in resistant swallowing disorders because SNr is involved in swallowing control.
Hypothesis:
In this study, we hypothesize that simultaneous deep brain stimulation of STN and SNr is more effective in preventing food inhalation in PD dysphagia than standard deep brain stimulation of STN at eight weeks of treatment.
Study Design:
SNr can be stimulated using a device for STN stimulation, and the two regions can be stimulated simultaneously. In the beginning of the study, we will evaluate swallowing in the absence of brain stimulation, during STN stimulation and during SNr stimulation. Then, swallowing will be evaluated in people receiving medication and in those receiving standard STN stimulation. After the assessment, study participants will be randomly assigned to receive either standard STN stimulation or simultaneous STN and SNr stimulation. In addition, all participants will receive swallowing therapy as a standard of care. Improvement in swallowing will be assessed after eight weeks of active treatment.
Impact on Diagnosis/Treatment of Parkinson's disease:
This study can provide the first insight into the effectiveness and safety of SNr stimulation for resistant dysphagia in advanced Parkinson's disease.
Next Steps for Development:
The study will reveal whether SNr stimulation is effective in improving PD-related swallowing impairment or otherwise resistant to treatment.