Bilateral STN stimulation does not slow progression of Parkinson's disease

For the first time, researchers have demonstrated a continuous decline of dopaminergic function in patients with advanced Parkinson's disease despite clinically effective bilateral subthalamic nucleus (STN) stimulation.Deep brain stimulation (DBS) of the STN is a highly effective treatment used for patients with advanced Parkinson's disease, and recent reports have demonstrated the long-term motor benefits of STN DBS in this patient group. It has been postulated that the reduction of STN neuronal hyperactivity by inhibition of high-frequent stimulation might slow or halt the progression of neurodegeneration in Parkinson's disease.Hilker et al. carried out a prospective study on the progression of Parkinson's disease in 30 patients following successful STN DBS measured with 18F-fluorodopa (F-dopa) positron emission tomography (PET).At the time of the 16-month follow-up PET scan, a significant clinical improvement caused by STN DBS was observed. The annual progression rates relative to baseline were found to be 9.5-12.4% in the caudate and 10.7-12.9% in the putamen. "From a clinical point of view, our PET data may help in maintaining realistic expectations about STN stimulation - that is, there is strong symptomatic relief but not a slowing of disease progression or even a cure of the disorder," the authors noted.The results of this study are the first to demonstrate that decline of dopaminergic function in advanced Parkinson's disease continues despite clinically effective bilateral STN stimulation. Therefore, neuroprotective properties of DBS in the STN target could not be confirmed.Reference...