medwireNews: Deep-brain stimulation (DBS) targeting the subthalamic nucleus with a multiple-source constant-current device effectively suppresses motor symptoms in patients with advanced Parkinson’s disease (PD), report researchers.
The 16-output, multiple-channel, constant-current device used in the study allows shaping of the electrical field, which the researchers hoped would minimise spread of the current to non-target tissue, thus reducing adverse effects and maximising therapeutic efficacy.
In a commentary accompanying the study in The Lancet Neurology, Michele Tagliati (Cedars Sinai Medical Center, Los Angeles, California, USA) praises the research, noting that “today’s neurostimulators are not fundamentally different from those initially used more than two decades ago.”
The results, he says, are “remarkable”, with the 38 patients achieving an average 62% improvement in their Unified Parkinson’s Disease Rating Scale part III (UPDRS III) score.
The patients’ devices were switched on 8–14 days after implantation and the settings were adjusted with the aim of obtaining the optimal clinical effect by week 26. By this point, the patients’ average UPDRS III score was 13.5, down from a baseline of 37.4. And this improvement was maintained through to week 52 of the study, when the patients’ average score was 13.7.
Furthermore, patients were able to reduce their average levodopa equivalent dose, from 1399.1 mg at baseline to 562.7 and 503.0 mg at weeks 26 and 52, respectively. Their diaries of on time showed that this increased by about 3 hours per day, and their quality of life also improved.
Adverse events were in line with those expected for DBS, with three adverse events attributed to the surgical operation (respiratory depression, device migration, implant-site infection) and none to stimulation. One patient died of pneumonia considered to be unrelated to implantation or stimulation.
Researcher Lars Timmermann (University Hospital Cologne, Germany) and team also tested the patients’ willingness to recharge their devices’ batteries, finding that this was “well tolerated”, with all patients doing it at least once during follow-up.
Although praising the novel DBS device, Tagliati stresses that it still “does not fulfill completely the needs and expectations of this area of research.”
He hopes for advanced electrode designs and new stimulation models, because “the future of DBS as a clinical and translational science will depend on our ability to unravel its mechanisms of action.”
Tagliati concludes: “Only when we better understand and control – versus empirically guess – the effects of DBS on the [central nervous system] will the revolutionary power of this technology fully exert its therapeutic promise.”
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