Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; ICORD, University of British Columbia, Vancouver, British Columbia, Canada; School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland.
J Neurosci Methods. 2019 Jun 1;321:20-27. doi: 10.1016/j.jneumeth.2019.04.003. Epub 2019 Apr 6.
Temporal changes of pain perception to prolonged tonic heat pain are conventionally assessed using a computerized visual analog scale. Such a rating-based approach is, however, prone to floor and ceiling effects, which limit the assessment of temporal changes in perception. Thus, alternative methods that overcome these shortcomings are warranted.
The aim of this study was to assess the feasibility and reliability of a psychophysical approach, i.e., participant-controlled temperature (PCT), to evaluate ongoing human perception of tonic heat pain. Fifty participants were presented with a 45 °C stimulus on the non-dominant hand, and were instructed to maintain their initial sensation for two minutes via a feedback controller in the dominant hand. A subset of participants (n = 17) performed PCT tonic heat protocols on two different days to determine the test-retest reliability. As participants controlled temperature to maintain a stable pain perception, any adjustments made reflected shifts in their perception of heat.
In 33 (71.7%) participants, we observed an initial adaptation (participant increased temperature) followed by temporal summation of pain (participant decreased temperature). Twelve participants (26.1%) showed only adaptation and one (2.2%) only temporal summation. No sex differences were observed, nor did the initial rating of pain have an effect on PCT outcomes. Temporal summation of pain showed moderate to substantial reliability upon retest.
PCT represents can be reliably performed using a contact heat stimulator to measure the temporal summation of pain. The standardized setup and overall good reliability of the outcome measures facilitate a sound implementation into the clinical work-up of patients with pain conditions.
传统上，使用计算机化视觉模拟量表评估长时间强直性热痛的疼痛感知的时间变化。然而，这种基于评分的方法容易出现地板效应和天花板效应，限制了对感知时间变化的评估。因此，需要有其他方法来克服这些缺点。
本研究的目的是评估一种心理物理方法，即参与者控制温度（PCT），评估持续强直性热痛的人类感知的可行性和可靠性。50 名参与者将在非优势手上接受 45°C 的刺激，并通过优势手上的反馈控制器指示他们将初始感觉维持两分钟。一部分参与者（n=17）在两天内进行了 PCT 强直性热痛方案，以确定测试-重测信度。由于参与者通过控制温度来保持稳定的疼痛感知，因此任何调整都反映了他们对热的感知变化。
在 33 名（71.7%）参与者中，我们观察到初始适应（参与者增加温度），随后是疼痛的时间总和（参与者降低温度）。12 名参与者（26.1%）仅显示适应，1 名参与者（2.2%）仅显示时间总和。未观察到性别差异，初始疼痛评分也对 PCT 结果没有影响。疼痛的时间总和在重测时具有中等至较大的可靠性。
PCT 可以使用接触热刺激器可靠地进行，以测量疼痛的时间总和。标准化的设置和整体良好的可靠性使该方法易于在疼痛患者的临床评估中实施。
