Use of 80 HZ stimulation in subthalamic deep brain stimulation parkinson's disase patients may improve axial symptoms and speech with longstanding effect.

Objectives: Bilateral subthalamic nucleus deep brain stimulation (STN DBS) remains an effective and long-lasting therapy for patients with advanced Parkinson's disease (PD). Some patients develop stimulation resistant symptoms like freezing of gait and gait disturbances in on condition. These axial symptoms in contrary to limb tremor, rigidity and bradykinesia are not well controlled by high frequency STN DBS over longer follow-up periods. Interestingly, we observed that unilateral single-channel internal pulse generator (IPG) depletion may improve paradoxically axial symptoms and gait. After replacement of IPG and changing the stimulation frequency from high (130m Hz) to low (80 Hz) the axial and limb PD symptoms were well controlled. The aim of the study was to evaluate 80 Hz stimulation in advanced PD patients after unilateral IPG depletion. Methods: We report on our experience in using low frequency 80 Hz bilateral STN DBS in 7 patients with longstanding PD. All patients experienced depletion of one IPG which paradoxically improved some axial symptoms. After replacement surgery and reinstitution of 130 Hz stimulation axial symptoms deteriorated. Subsequent lowering stimulation frequency to 80 Hz improved axial symptoms. The objective assessments included the UPDRS part II and III, Stand-Walk-Sit (SWS) test during 130 Hz and 80 Hz stimulation in medication off and on condition. Results: We observed significant improvement of axial scores and gait after switching from 130 Hz to 80 Hz stimulation frequency. The gait (SWS) test and gait disorder scores of UPDRS part III improvements were clearly demonstrated in stimulation on 80 Hz condition. Interestingly, speech also improved under bilateral 80 Hz stimulation. In some patients the voltage had to be increased to better control segmental PD symptoms. Conclusion: Rapid depletion of single channel IPG programmed with high frequency stimulation 130 Hz results in simultaneous improvement of axial symptoms like freezing of gait in on condition reported by the patients themselves. It can be concluded that bilateral 130 Hz in STN DBS may not be the preferred frequency for continuous stimulation and may impair some gait and balance problem seen in PD patients. Lowering the frequency to 80 Hz solved these problems in reported patients. [ABSTRACT FROM AUTHOR]