神經調節術在疼痛治療的新進展

Recent Progress of Neuromodulation in Pain Treatment

近年非侵襲性腦刺激術（non-invasive brain stimulation, NIBS）有很大的進展，幾乎所有神經科領域疾病都可能應用此項技術，相關研究並已擴及精神科的疾病。原則上，所有的物理能量形式，例如：電流、磁場、超音波和光，皆可做為NIBS的刺激源。目前最常用的能量形式為電流和磁場，聚焦超音波則是最近新增之利器。運用電流做為刺激源時，電流的形式可以是直流電（穿顱直流電刺激）或是交流電（穿顱交流電刺激）。磁場刺激可以是脈衝式單發（穿顱磁刺激）或是連續性的（重複性穿顱磁刺激）。以NIBS來治療疼痛，需要考慮施予刺激的位置。疼痛傳導至腦部的主要路徑有兩條，一為傳導至感覺皮質，讓我們感受到痛的位置和性質，另一則為傳導至邊緣系統，讓我們感受到痛的不舒服感和引起情緒反應。雖然有許多研究依照疼痛路徑來設計刺激位置，然而目前有療效證據的研究結果，其有效刺激位置並不在這些疼痛路徑上。本文除了針對上述NIBS的原理和疼痛在腦部的解剖位置做簡述之外，對於NIBS各項技術在具有實證的特定疾病所造成疼痛之運用，再做較為深入的介紹。

Recently, there has been a great progress in non-invasive brain stimulation, (NIBS), covering almost all diseases in Neurology and Psychiatry. In principle, all common physical forms of energy, such as electricity, magnetism, ultrasound and light, can be adopted as the stimulating source of NIBS. Currently most widely used sources are electricity and magnetism, while focused ultrasound is rising up very quickly. When electricity is used as the source, the transcranial stimulation can be direct current (tDCS) or alternating current (tACS). On the other hand, the transcranial magnetic stimulation (TMS) can be pulsatic singlet or doublet, or repetitive (rTMS). When using NIBS to treat pain, the stimulation location needs to be considered first. There are two main afferent pathways conducting pain information to the brain, including one projecting to the primary sensory cortex that transmits the objective information about the location and type of pain, and the other projecting to the limbic system that provokes uncomfortableness and emotional reaction. Though many studies designed the stimulation location according to the pain pathway, the study results did not support their hypotheses. In this article, the principle of NIBS and the pain anatomy in the brain are briefly reviewed and the current status and evidences supporting the effectiveness of NIBS in treating pain from specific diseases are described.