BACKGROUND Deep Brain Stimulation (DBS) targeting the subthalamic nucleus (STN) and globus pallidus interna (GPi) is an effective treatment for cardinal motor symptoms and motor complications in Parkinson's Disease (PD). However, malpositioned DBS electrodes can result in suboptimal therapeutic response. OBJECTIVE We explored whether recovery of the H-reflex-an easily measured electrophysiological analogue of the stretch reflex, known to be altered in PD-could serve as an adjunct biomarker of suboptimal versus optimal electrode position during STN- or GPi-DBS implantation. METHODS Changes in soleus H-reflex recovery were investigated intraoperatively throughout awake DBS target refinement across 26 nuclei (14 STN). H-reflex recovery was evaluated during microelectrode recording (MER) and macrostimulation at multiple locations within and outside target nuclei, at varying stimulus intensities. RESULTS Following MER, H-reflex recovery normalized (i.e., became less Parkinsonian) in 21/26 nuclei, and correlated with on-table motor improvement consistent with an insertional effect. During macrostimulation, H-reflex recovery was maximally normalized in 23/26 nuclei when current was applied at the location within the nucleus producing optimal motor benefit. At these optimal sites, H-reflex normalization was greatest at stimulation intensities generating maximum motor benefit free of stimulation-induced side effects, with subthreshold or suprathreshold intensities generating less dramatic normalization. CONCLUSION H-reflex recovery is modulated by stimulation of the STN or GPi in patients with PD and varies depending on the location and intensity of stimulation within the target nucleus. H-reflex recovery shows potential as an easily-measured, objective, patient-specific, adjunct biomarker of suboptimal versus optimal electrode position during DBS surgery for PD.

中文翻译：

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帕金森病脑深部刺激手术期间 H 反射通路的术中变化：最佳电极放置的潜在生物标志物

背景针对丘脑底核（STN）和苍白球内部（GPi）的深部脑刺激（DBS）是治疗帕金森病（PD）的主要运动症状和运动并发症的有效方法。然而，错位的 DBS 电极会导致次优的治疗反应。目标我们探讨了 H 反射的恢复 - 一种易于测量的牵张反射的电生理类似物，已知在 PD 中发生改变 - 是否可以作为 STN 或 GPi-DBS 植入期间次优电极位置与最佳电极位置的辅助生物标志物。方法 在整个清醒 DBS 目标细化过程中，在 26 个细胞核 (14 STN) 中研究了比目鱼肌 H 反射恢复的变化。在微电极记录 (MER) 和宏观刺激期间，在不同刺激强度下，在靶核内外的多个位置评估 H 反射恢复。结果 MER 后，H 反射恢复在 21/26 细胞核中正常化（即，帕金森病减少），并且与与插入效应一致的桌上运动改善相关。在宏观刺激期间，当电流施加在细胞核内产生最佳运动益处的位置时，H 反射恢复在 23/26 细胞核中最大程度地正常化。在这些最佳部位，H 反射正常化在刺激强度下最大，产生最大的运动益处，没有刺激引起的副作用，阈下或阈上强度产生的正常化不太显着。结论 H 反射恢复受 PD 患者 STN 或 GPi 刺激的调节，并根据靶核内刺激的位置和强度而变化。H 反射恢复显示出作为一种易于测量的、客观的、患者特异性的、辅助生物标志物的潜力，用于 PD 的 DBS 手术期间次优与最佳电极位置。