Long-term Effect of Low Frequency 60Hz Stimulation on Aspiration, Freezing of Gait and Other Axial and Motor Symptoms in PD Patients With Bilateral STN DBS

Our recent study (Xie et al, Neurology 2015; 84: 415-420) found that bilateral STN DBS of 60Hz, compared to the traditional 130Hz, decreased the aspiration frequency and swallowing difficulty, freezing of gait (FOG), and other axial symptoms and parkinsonism in Parkinson patients with FOG refractory to 130Hz and medications. The benefit of 60Hz stimulation persisted during the 6-week study period, but with worsening tremor in one patient. However, it remains unknown whether the benefit of 60Hz would persist on prolonged stimulation period, and whether there is carry-over effect across different conditions. Hence, the investigators would like to test the hypothesis that the 60Hz stimulation, compared to 130Hz might have persistent benefit over an extended period in reducing the swallowing dysfunction, FOG, and other axial symptoms in these PD patients even after correcting the potential carry-over effect.