Supplementary Material for: Confined Thalamic Deep Brain Stimulation in Refractory Essential Tremor

Background: Thalamic ventral intermediate nucleus (VIM) deep brain stimulation (DBS) is an effective therapy for medication-refractory essential tremor (ET). However, 13–40% of patients with an initially robust tremor efficacy lose this benefit over time despite reprogramming attempts. At our institution, a cohort of ET patients with VIM DBS underwent implantation of a second anterior (ventralis oralis anterior; VOA) DBS lead to permit “confined stimulation.” We sought to assess whether confined stimulation conferred additional tremor capture compared to VIM or VOA stimulation alone. Methods: Seven patients participated in a protocol-based programming session during which a video-recorded Fahn-Tolosa-Marin Part A (FTM-A) tremor rating scale was used in the following 4 DBS states: off stimulation, VIM stimulation alone, VOA stimulation alone, and dual lead (confined) stimulation. Results: The average (SD) baseline FTM-A off score was 17.6 (4.0). VIM stimulation alone lowered the average FTM-A total score to 6.9 (4.0). Confined stimulation further attenuated the tremor, reducing the total score to 5.7 (2.8). Conclusions: Confined thalamic DBS can provide additional symptomatic benefits in patients with unsatisfactory tremor control from VIM or VOA stimulation alone.

背景：丘脑腹中间核（Thalamic ventral intermediate nucleus, VIM）深部脑刺激（Deep Brain Stimulation, DBS）是治疗药物难治性原发性震颤（Essential Tremor, ET）的有效疗法。然而，尽管尝试了刺激参数重编程，仍有13%~40%初始震颤控制效果显著的患者随时间推移逐渐丧失该治疗获益。在本研究所属机构中，一批接受VIM DBS治疗的ET患者植入了第二根前丘脑（腹前核前区, VOA）DBS电极，以实现"局限化刺激"。本研究旨在评估相较于单独VIM或VOA刺激，局限化刺激能否为患者带来额外的震颤控制获益。
方法：共有7名患者参与了标准化程控测试，测试期间通过视频记录的方式采用Fahn-Tolosa-Marin震颤评定量表A部分（FTM-A）对以下4种DBS状态进行评分：无刺激状态、单独VIM刺激状态、单独VOA刺激状态以及双电极（局限化）刺激状态。
结果：无刺激状态下的基线平均FTM-A总分为17.6（标准差4.0）。单独VIM刺激可将平均FTM-A总分降至6.9（标准差4.0）。局限化刺激可进一步减轻震颤，将平均总分降至5.7（标准差2.8）。
结论：相较于单独VIM或VOA刺激，局限化丘脑DBS可为单独使用该两种刺激方式仍无法获得满意震颤控制的患者提供额外的症状改善获益。