Less Is More: Adaptation of Voltage after Battery Replacement in Deep Brain Stimulation for Dystonia

Abstract

Background: To maintain the efficacy of deep brain stimulation (DBS) on dystonic symptoms, slight incremental increase in voltage may be necessary over years after a steady state has been reached following the initial programming of optimal settings. So far however, no data are available regarding the adjustment of voltage after implantable pulse generator (IPG) replacement to achieve sustained optimal control of dystonia with the least side effects. Methods: We analyzed stimulation settings before and after IPG replacement for battery depletion (n = 61) in 18 patients with chronic DBS of the globus pallidus internus or the ventral intermediate nucleus of the thalamus for dystonia. Results: The stimulation intensity could be significantly reduced by 24.8% after IPG replacement. The amount of voltage reduction was equal between bipolar and monopolar stimulation modes (24.9 vs. 24.3%, p = 0.89) and significantly correlated with the magnitude of stimulation intensity before IPG replacement (ρ = 0.429, p = 0.001). Conclusions: After IPG replacement, in patients with DBS for segmental dystonia the voltage can be reduced by approximately 25%. This phenomenon might be explained by a gradual decrease in the electrical energy effectively delivered by the IPG in the course of the lifetime of the battery or neuroplastic processes in particular in the period around battery replacement.

Rechargeable Internal Neural Stimulators—Is There a Problem with Efficacy?

“…For the patient who had the same efficacy at the lower end of the previous voltage range, this has been reported previously in patients with dystonia undergoing INS replacement (8). This could be due to a gradual decrease in energy delivered by the INS in the course of the lifetime of the battery (8).…”

Clinical Efficacy of Bilateral Deep Brain Stimulation Does Not Change After Implantable Pulse Generator Replacement but the Impedances Do: A Prospective Study

“…In accordance with observations like these, some authors tend to broadly decrease stimulation settings after elective IPG replacement . Waln et Jimenez‐Shahed reported conversion parameters for 14 PD, ET, dystonia, and TS patients receiving Activa® RC following a depletion of Soletra® (Model 7426, Medtronic) IPGs.…”

“…Prolonged IPG longevity and, correspondingly, less frequent IPG replacements might diminish the complications following highly recurrent IPG replacements, such as increasing infection rates and decreasing IPG longevity . Independent of the IPG model, however, there still seems to be limited knowledge of these elective replacements and the resulting clinical efficacy . Various authors repeatedly reported reduced symptom control in some patients after IPG replacement and others tend to generally decrease stimulation settings after those surgeries .…”

“…Independent of the IPG model, however, there still seems to be limited knowledge of these elective replacements and the resulting clinical efficacy . Various authors repeatedly reported reduced symptom control in some patients after IPG replacement and others tend to generally decrease stimulation settings after those surgeries . However, none of those authors reported objective clinical proof of that concept.…”

Bilateral Pallidal Stimulation for “Sticking-Out Tongue” Feature in Patients With Primary Focal Tongue Protrusion Dystonia

“…However, we maintained a relatively a low level of parameters for about two years and finally achieved more than 92% improvement in both patients. In recently published study, low‐amplitude stimulation is appropriate to attain a sustained clinical and functional control of segmental dystonia . Our previous report also suggested that the initial setting as lower parameter after DBS surgery is most important to maintain other benefits in cervical dystonia .…”