Short pulse width in subthalamic stimulation in Parkinson's disease: a randomized, double‐blind study

Abstract

width range, current steering, and other programmable features of the device. It is not possible to test all settings in a single programming visit, and more studies are needed to define the optimal parameter space for target signs.Another limitation was the lack of data on efficacy of chronic stimulation at a short pulse width. The participants were only exposed to each stimulation setting for a short time during a single programming visit; it is possible that long-term stimulation would have revealed differences between short and conventional pulse widths that were not apparent during the acute visit. However, the blinded assessment of motor signs (UPDRS III) during an acute stimulation challenge has previously been used as the primary efficacy endpoint in DBS studies [8][9][10] and reflected the chronic benefit of DBS.Despite these limitations, few controlled studies are aimed at achieving optimization of DBS programming, and this is the first double-blind assessment of the effect of a shorter pulse width and 1 of only a handful of DBS programming studies that have ever been conducted in a double-blind condition.In conclusion, stimulation using a shorter than currently recommended pulse width may be more efficient at achieving therapeutic efficacy and less likely to reach a side effect threshold. This may translate into a fundamentally new basic parameter setting for patients with DBS in PD. Supporting DataAdditional Supporting Information may be found in the online version of this article at the publisher's website. Short Pulse Width in AbstractBackground: We investigated the acute effect of short pulse widths on the therapeutic window in subthalamic nucleus deep brain stimulation in Parkinson's disease. Methods: We assessed 10 PD patients with STN-DBS at a 60-ms pulse width. We randomly and doubleblindedly applied 10-to 50-ms pulse widths. The principal outcome was the therapeutic window (difference --

Short Versus Conventional Pulse‐Width Deep Brain Stimulation in Parkinson's Disease: A Randomized Crossover Comparison

“…We also did not note any differences in motor assessments, nonmotor symptoms, or quality‐of‐life measures after 4 weeks of treatment using short PW stimulation. The therapeutic window during the monopolar review was significantly greater at 30‐μs compared with 60‐μs, consistent with the findings of previous studies …”

“…A consistent finding across multiple studies and one of the proposed mechanisms by which the therapeutic window is increased by using short PW stimulation is that a lower charge is required to achieve the therapeutic effect when compared with standard PW . Given that stimulation settings tend to be increased over time in chronic patients, it is possible that the reduction in charge at thresholds for therapeutic effect at short PW in these patients is not sufficient to alleviate side effects because of the higher absolute electrical charge delivered.…”

“…The therapeutic window during the monopolar review was significantly greater at 30-μs compared with 60-μs, consistent with the findings of previous studies. [16][17][18][19] Although the acute effect of short PW on the therapeutic window has been well documented, our trial is the first to examine short PW stimulation in STN-DBS beyond the setting of an acute challenge. The study was not designed to assess efficacy; however, our data suggest that using a PW of 30-μs has a sustained therapeutic effect similar to 60-μs PW at 4 weeks' duration.…”

“…Although 60‐μs has been the recommended PW for STN stimulation based on the finding of having the widest therapeutic window in the conventional parameter range, some newer devices have expanded the available range by enabling the use of shorter PWs. Multiple recent studies have confirmed the expected increase in therapeutic window (measured in terms of current amplitude) by the use of shorter than conventional PW in the acute setting . A proposed mechanism by which altering PW may reduce side effects is the notion of fiber selectivity and avoiding the stimulation of neural elements that mediate unwanted effects.…”

“…Multiple recent studies have confirmed the expected increase in therapeutic window (measured in terms of current amplitude) by the use of shorter than conventional PW in the acute setting. [16][17][18][19] A proposed mechanism by which altering PW may reduce side effects is the notion of fiber selectivity and avoiding the stimulation of neural elements that mediate unwanted effects. There is growing evidence for the utility of short PW stimulation of thalamic targets in patients with tremor who experience stimulation induced ataxia.…”