Nie HongLing, Graven-Nielsen Thomas, Arendt-Nielsen Lars
Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
Eur J Pain. 2009 Jul;13(6):592-9. doi: 10.1016/j.ejpain.2008.07.013. Epub 2008 Oct 15.
Chronic pain patients often suffer from widespread and long lasting pain. The integrative effect of combined spatial and temporal summation on pain intensity has not been quantitatively tested. The present study was designed to investigate: (1) if the size of the stimulation area would facilitate the temporal summation of pain to repetitive pressure stimulation, and (2) if temporal summation is effective when stimulating separated sites, repetitively. Twenty healthy male subjects participated in this study. The test sites were located on the bilateral upper trapezius and tibialis anterior muscles. The ten stimuli (each with a duration of 1s) were applied to a single site at three inter-stimulus intervals (ISI: 1, 5, 30s) using five different probe sizes (0.5, 1, 2, 4 and 8cm(2)). The stimulation intensity was equal to the pressure pain threshold (PPT) determined for each probe size. Similar repetitive stimulations at two inter-stimulus intervals (5s and 30s) using two sizes of probes (0.5cm(2) and 2cm(2)) were applied to ten separate sites. The PPT at the trapezius muscle decreased significantly with the increase in stimulus area from 0.5cm(2) to 8cm(2) (P<0.001) due to spatial summation. Temporal summation of pain was evoked by repetitive pressure stimuli on the same site for all ISI and was more pronounced at 5s and 30s ISI with larger probe areas (2, 4, and 8cm(2)) compared to smaller probe areas. There was no temporal summation of pain to stimuli with ISI 5 and 30s when stimulating the separated sites. The current study indicated that spatial summation facilitated the temporal summation of pain for stimuli given at 5s and 30s ISI. The combination of temporal and spatial integration of nociceptive input facilitates the pain intensity, suggesting that temporal summation is clinically relevant in conditions with widespread pain.
慢性疼痛患者常常遭受广泛且持久的疼痛。空间和时间总和对疼痛强度的综合影响尚未进行定量测试。本研究旨在调查：（1）刺激区域的大小是否会促进对重复性压力刺激的疼痛时间总和，以及（2）当重复刺激分开的部位时，时间总和是否有效。20名健康男性受试者参与了本研究。测试部位位于双侧上斜方肌和胫骨前肌。使用五种不同的探头大小（0.5、1、2、4和8平方厘米），以三种刺激间隔（ISI：1、5、30秒）将十个刺激（每个持续1秒）施加到单个部位。刺激强度等于为每个探头大小确定的压力疼痛阈值（PPT）。使用两种探头大小（0.5平方厘米和2平方厘米），以两种刺激间隔（5秒和30秒）对十个分开的部位进行类似的重复刺激。由于空间总和，斜方肌处的PPT随着刺激面积从0.5平方厘米增加到8平方厘米而显著降低（P<0.001）。对于所有ISI，在同一部位的重复性压力刺激诱发了疼痛的时间总和，与较小的探头面积相比，在5秒和30秒ISI且探头面积较大（2、4和8平方厘米）时更为明显。当刺激分开的部位时，对于ISI为5秒和30秒的刺激没有疼痛的时间总和。当前研究表明，空间总和促进了在5秒和30秒ISI给予刺激时疼痛的时间总和。伤害性输入的时间和空间整合的组合促进了疼痛强度，表明时间总和在广泛疼痛的情况下具有临床相关性。
