Center for Neuroplasticity and Pain (CNAP), Aalborg University, Denmark.
Center for Neuroplasticity and Pain (CNAP), Aalborg University, Denmark.
J Pain. 2021 Aug;22(8):952-967. doi: 10.1016/j.jpain.2021.02.012. Epub 2021 Mar 4.
Chronic low back pain (CLBP) is highly disabling, but often without identifiable source. Focus has been on impaired anti-nociceptive mechanisms contributing to pain maintenance, though methods of targeting this impairment remain limited. This randomised-controlled cross-over pilot trial used active versus sham medial prefrontal cortex (mPFC) high-definition transcranial direct current stimulation (HD-tDCS) for 3-consecutive days to improve descending pain inhibitory function. Twelve CLBP patients were included with an average visual analogue scale (VAS) pain intensity of 3.0 ± 1.5 and pain duration of 5.3 ± 2.6 years. Pressure pain thresholds (PPTs), conditioned pain modulation (CPM), and temporal summation of pain (TSP) assessed by cuff algometry, as well as pain symptomatology (intensity, unpleasantness, quality, disability) and related psychological features (pain catastrophizing, anxiety, affect), were assessed on Day1 before 3 consecutive days of HD-tDCS sessions (each 20 minutes), at 24-hours (Day 4) and 2-weeks (Day 21) following final HD-tDCS. Blinding was successful. No significant differences in psychophysical (PPT, CPM, TSP), symptomatology or psychological outcomes were observed between active and sham HD-tDCS on Day4 and Day21. CPM-effects at Day 1 negatively correlated with change in CPM-effect at Day4 following active HD-tDCS (P = .002). Lack of efficacy was attributed to several factors, not least that patients did not display impaired CPM at baseline. TRIAL REGISTRATION: : ClinicalTrials.gov (NCT03864822). PERSPECTIVE: Medial prefrontal HD-tDCS did not alter pain, psychological nor psychophysical outcomes, though correlational analysis suggested response may depend on baseline pain inhibitory efficacy, with best potential effects in patients with severe impairments in descending pain inhibitory mechanisms. Future work should focus on appropriate patient selection and optimising stimulation targeting.
慢性下背痛（CLBP）高度致残，但通常没有明确的病因。研究重点一直放在受损的抗伤害机制上，这些机制导致疼痛持续存在，尽管针对这种损伤的方法仍然有限。本项随机对照交叉先导试验使用经颅直流电刺激（HD-tDCS）对内侧前额叶皮层（mPFC）进行 3 天的主动刺激与假刺激，以改善下行性疼痛抑制功能。共纳入 12 名 CLBP 患者，平均视觉模拟评分（VAS）疼痛强度为 3.0 ± 1.5，疼痛持续时间为 5.3 ± 2.6 年。使用袖带测痛法评估压力疼痛阈值（PPT）、条件性疼痛调制（CPM）和疼痛时间总和（TSP），以及疼痛症状（强度、不适、质量、残疾）和相关心理特征（疼痛灾难化、焦虑、情绪），在 Day1 进行评估，包括 3 天的 HD-tDCS 治疗（每天 20 分钟），在 24 小时（Day 4）和最后一次 HD-tDCS 后 2 周（Day 21）。结果显示，盲法成功。在 Day4 和 Day21 时，主动和假刺激 HD-tDCS 之间在心理物理学（PPT、CPM、TSP）、症状或心理结果方面没有显著差异。Day1 的 CPM 效应与主动 HD-tDCS 后 Day4 的 CPM 效应变化呈负相关（P =.002）。缺乏疗效归因于几个因素，尤其是患者在基线时没有表现出受损的 CPM。试验注册：ClinicalTrials.gov（NCT03864822）。观点：内侧前额叶皮层的 HD-tDCS 并没有改变疼痛、心理或心理物理结果，尽管相关性分析表明反应可能取决于基线疼痛抑制效果，对于严重受损的下行性疼痛抑制机制的患者可能具有最佳的潜在效果。未来的工作应侧重于适当的患者选择和优化刺激靶向。
