Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg Øst, Denmark.
Pain. 2015 Mar;156(3):555-564. doi: 10.1097/01.j.pain.0000460332.41009.4a.
The nociceptive withdrawal reflex (NWR) is a polysynaptic spinal reflex correlated with pain perception. Assessment of this objective physiological measure constitutes the core of existing methods for quantification of reflex receptive fields (RRFs), which however still suffer from a certain degree of subjective involvement. This article proposes a strictly objective methodology for RRF quantification based on automated identification of NWR thresholds (NWR-Ts). Nociceptive withdrawal reflex thresholds were determined for 10 individual stimulation sites using an interleaved up-down staircase method. Reflexes were detected from electromyography by evaluation of interval peak z scores and application of conduction velocity analysis. Reflex receptive field areas were quantified from interpolated mappings of NWR-Ts and compared with existing RRF quantifications. A total of 3 repeated measures were performed in 2 different sessions to evaluate the test-retest reliability of the various quantifications, using coefficients of repeatability (CRs) and hypothetical sample sizes. The novel quantifications based on identification of NWR-Ts showed a similar level of reliability within and between sessions, whereas existing quantifications all demonstrated worse between-session than within-session reliability. The NWR-T-based quantifications required a smaller sample size than any of the existing RRF measures to detect a clinically relevant effect in a crossover study design involving more than 1 session. Of all measures, quantification from mapping of inversed NWR-Ts demonstrated superior reliability both within (CR, 0.25) and between sessions (CR, 0.28). The study presents a more reliable and robust quantification of the RRF to be used as biomarker of pain hypersensitivity in clinical and experimental research.
伤害性退缩反射（NWR）是一种与疼痛感知相关的多突触脊髓反射。评估这种客观的生理测量构成了现有反射感受野（RRF）量化方法的核心，然而这些方法仍然存在一定程度的主观参与。本文提出了一种基于自动识别伤害性退缩反射阈值（NWR-T）的严格客观的 RRF 量化方法。使用交错上下楼梯法，对 10 个个体刺激部位的伤害性退缩反射阈值进行了确定。通过评估间隔峰值 z 分数和应用传导速度分析，从肌电图中检测到反射。通过对 NWR-T 的插值映射来量化反射感受野区域，并与现有的 RRF 量化方法进行比较。在 2 个不同的会话中进行了 3 次重复测量，以使用可重复性系数（CR）和假设样本量来评估各种量化方法的测试-再测试可靠性。基于识别 NWR-T 的新量化方法在内部和外部会话中显示出相似的可靠性水平，而现有的量化方法则都显示出比内部会话更差的外部会话可靠性。与任何现有的 RRF 测量相比，基于 NWR-T 的量化方法在涉及多个会话的交叉研究设计中检测到临床相关效果所需的样本量更小。在所有测量中，从反转 NWR-T 的映射中进行量化在内部（CR，0.25）和外部会话（CR，0.28）中都显示出更好的可靠性。该研究提出了一种更可靠和更稳健的 RRF 量化方法，可作为临床和实验研究中疼痛超敏的生物标志物。
