TY - JOUR
T1 - Spatial summation of pain in humans investigated using transcutaneous electrical stimulation
AU - Reid, Emily
AU - Harvie, Daniel
AU - Miegel, Rohan
AU - Spence, Charles
AU - Moseley, G Lorimer
N1 - Funding Information:
The authors declare that they have no competing interests that are directly related to the content of this manuscript. D.H. is supported by a postgraduate award from the Australian Government , and the Vice Chancellor's award from the University of South Australia . G.L.M. is supported by a research fellowship from the National Health & Medical Research Council of Australia (ID 1061279 ). This study was supported by NHMRC Grant ID 1008017 .
Publisher Copyright:
© 2015 American Pain Society.
PY - 2015/1
Y1 - 2015/1
N2 - Spatial summation of pain is well accepted but surprisingly understudied. Area-based summation refers to the increase in pain evoked by increasing the area of stimulation. Distance-based summation refers to the increase in pain evoked by increasing the distance between multiple stimuli. Although transcutaneous electrical stimulation has several advantages over other experimental pain paradigms, whether or not this modality evokes spatial summation remains unknown. We aimed to answer this question in order to lay the foundation for critical studies of spatial summation. Twenty-five healthy participants received stimuli on their forearm, and the primary outcome, pain intensity, was compared across 5 spatial configurations-1 with a single stimulus and 4 paired configurations at 0-, 5-, 10-, and 20-cm separations. Importantly, the potential confounder of a proximal-distal gradient in nociceptive sensitivity was removed in this study. Pain intensity was higher in response to the paired stimuli than in response to the single stimulus (P < .001), and the paired stimuli separated by 5, 10 and 20 cm, evoked greater pain than stimuli at a separation of 0 cm (P < .001), thus confirming both area- and distance-based summation, respectively. We conclude that transcutaneous electrical stimulation is appropriate for future investigations of spatial summation.PERSPECTIVE: Distance-based summation is likely implicated in some clinical pain. However, current understanding for spatial summation is limited. This study demonstrates that transcutaneous electrical stimulation is safe, feasible, and valid for future investigations of spatial summation and will allow critical questions to be answered.
AB - Spatial summation of pain is well accepted but surprisingly understudied. Area-based summation refers to the increase in pain evoked by increasing the area of stimulation. Distance-based summation refers to the increase in pain evoked by increasing the distance between multiple stimuli. Although transcutaneous electrical stimulation has several advantages over other experimental pain paradigms, whether or not this modality evokes spatial summation remains unknown. We aimed to answer this question in order to lay the foundation for critical studies of spatial summation. Twenty-five healthy participants received stimuli on their forearm, and the primary outcome, pain intensity, was compared across 5 spatial configurations-1 with a single stimulus and 4 paired configurations at 0-, 5-, 10-, and 20-cm separations. Importantly, the potential confounder of a proximal-distal gradient in nociceptive sensitivity was removed in this study. Pain intensity was higher in response to the paired stimuli than in response to the single stimulus (P < .001), and the paired stimuli separated by 5, 10 and 20 cm, evoked greater pain than stimuli at a separation of 0 cm (P < .001), thus confirming both area- and distance-based summation, respectively. We conclude that transcutaneous electrical stimulation is appropriate for future investigations of spatial summation.PERSPECTIVE: Distance-based summation is likely implicated in some clinical pain. However, current understanding for spatial summation is limited. This study demonstrates that transcutaneous electrical stimulation is safe, feasible, and valid for future investigations of spatial summation and will allow critical questions to be answered.
UR - http://www.scopus.com/inward/record.url?scp=84919360762&partnerID=8YFLogxK
U2 - 10.1016/j.jpain.2014.10.001
DO - 10.1016/j.jpain.2014.10.001
M3 - Article
C2 - 25463249
SN - 1528-8447
VL - 16
SP - 11
EP - 18
JO - Journal of Pain
JF - Journal of Pain
IS - 1
ER -