Effects of jaw muscle pain on jaw muscle activity and jaw movement in humans

慢性面部肌肉疼痛是一个重大的社区健康问题，人们对此知之甚少。目前的治疗方法是基于这样一种观点，即结构性或与压力相关的因素会导致下颌肌肉活动增加，然后产生疼痛，进而导致更多的肌肉活动--所谓的恶性循环理论。因此，治疗的目的是通过专注于减少肌肉活动来打破这种循环，从而减轻疼痛。然而，目前几乎没有科学证据支持这一理论。最近在疼痛适应模型中提出了另一种理论。这个模型说，肌肉活动和运动的变化是为了防止进一步的疼痛，而不是疼痛的原因。然而，支持这一模式的证据是有限的，而且相互矛盾。目前对面部肌肉疼痛缺乏了解，限制了其管理的进步。我们的长期目标是改善面部疼痛患者的管理。本应用旨在确定肌肉疼痛是否会改变下颌肌肉活动和下颌运动。我们的初步临床数据为疼痛适应模型提供了令人信服的证据。我们有信心更好地了解慢性面部疼痛时下颌肌肉的问题，这将对身体其他部位的肌肉疼痛产生影响。这一结果可能有助于驳斥恶性循环理论，并有助于将重点从与颌部肌肉相关的体征和症状转移，并将重点重新定向到减轻疼痛作为首要管理目标。所获得的信息还应该提供坚实的基础，可以在此基础上测试治疗以最佳地解决症状，并为面部疼痛的管理提供循证方法。

Chronic facial muscle pain is a significant community health problem that is poorly understood. Current treatments are based on the idea that structural or stress-related factors result in increased jaw muscle activity which then generates pain that in turn leads to more muscle activity - the so-called Vicious Cycle Theory. Treatments therefore aim to break the cycle by focussing on reducing muscle activity and thereby alleviate the pain. There is currently, however, little scientific evidence for this Theory. Another theory has been recently proposed in the Pain Adaptation Model. This model says that changes in muscle activity and movement are protective against further pain rather than the cause of the pain. The evidence, however, for this model is limited and conflicting. The current lack of understanding of facial muscle pain limits advancement in its management. Our long-term goal is to improve the management of patients with facial pain. The present application aims to determine whether muscle pain alters jaw muscle activity and jaw movement. Our preliminary clinical data provide compelling evidence for the Pain Adaptation Model. We are confident of a better understanding of what goes wrong in the jaw muscles in chronic facial pain and this will have implications for muscle pains elsewhere in the body. The outcome may help to refute the Vicious Cycle Theory, and help shift the focus away from signs and symptoms associated with the jaw muscles, and re-direct the focus to the alleviation of pain as the primary management goal. The information obtained should also provide a solid basis on which treatments can be tested for optimal resolution of symptoms, and an evidence-based approach in the management of facial pain.