A randomized crossover trial of short versus conventional pulse width DBS in Parkinsons Disease

Background: Subthalamic nucleus deep brain stimulation is a well-established treatment for patients with Parkinson`s disease. Previous acute challenge studies suggested that short pulse widths might increase the therapeutic window while maintaining motor symptom control. Objectives: To investigate in patients with Parkinson`s disease and nucleus subthalamicus deep brain stimulation (STN-DBS) whether short pulse width stimulation with 30μs maintains equal motor control as conventional 60μs stimulation over a period of 4 weeks. Methods: In this monocentric, double-blinded, randomized crossover trial, 30 patients with Parkinson`s disease and STN-DBS were enrolled and assigned to 4 weeks of stimulation with 30μs and 4 weeks of stimulation with 60μs in randomized order (German Clinical Trials Register No. DRKS00017528). The primary outcome was the difference in motor symptom control as assessed by a motor diary. Secondary outcomes included energy consumption measures, non-motor effects, side-effects, and quality of life. Results: A total of 24 patients were included in the final analysis. There was no difference in motor symptom control between the two treatment conditions. Concerning secondary outcomes there was no difference in energy consumption, non-motor symptoms, side-effects, or quality of life. On the individual level, patients preferring 30μs tended to be more dyskinetic in the 60μs setting, whereas patients preferring 60μs experienced more off-time in the 30μs setting. Conclusions: Short pulse width settings (30μs) provide equal motor symptom control as conventional (60μs) stimulation without significant differences in energy consumption. Future studies are warranted to evaluate a potential benefit of short pulse width settings in patients with pronounced dyskinesia.

Endurance of Short Pulse Width Thalamic Stimulation Efficacy in Intention Tremor

The benefit of short pulse width stimulation in patients suffering from essential tremor (ET) refractory to thalamic deep brain stimulation remains controversial. Here, we add to the minimal body of evidence available by reporting the effect of this type of stimulation in 3 patients with a persistent and severe intention tremor component despite iterative DBS setting adjustments. While a reduction in pulse width to 30 μs initially showed promise in these patients by improving tremor control and mitigating cerebellar side effects arguably by widening the therapeutic window, these benefits seemed to dissipate during early follow-up. Our experience supports the need for measuring longer-term outcomes when reporting the usefulness of this mode of stimulation in ET.

Effects of Cathode Voltage Pulse Width in High Power Impulse Magnetron Sputtering on the Deposited Chromium Thin Films

Environmentally-safe high-power impulse magnetron sputtering (HiPIMS) technology was utilized to deposit chromium films. This research focused on the influences of the HiPIMS pulse widths on the microstructure of films deposited at different deposition pressures and substrate bias voltages. Under the conditions of the same average HiPIMS power and duty cycle, the deposition rate of the Cr thin film at working pressure 0.8 Pa is slightly higher than at 1.2 Pa. Also, the difference between deposition rates under two pressures decreases with the discharge pulse width. The deposition rate of the short pulse width 60 μs is lowest, but those of 200 and 360 μs are approximately the same. With no or small direct current substrate biasing, the microstructure of films coated at short pulse width is similar to the typical magnetron sputtering deposited films. Elongating the pulse width enhances the ion flux toward the substrate and changes the film structure from individual prism-like columns into tangled 3-point/4-point star columns. Substantial synchronized substrate biasing and longer pulse width changes the preferred orientation of Cr films from Cr (110) to Cr (200) and Cr (211). The films deposited at longer pulse width exhibit a higher hardness due to the reducing of intercolumn voids.