TY - JOUR
T1 - Sex differences in temporal summation of pain and aftersensations following repetitive noxious mechanical stimulation
AU - Sarlani, Eleni
AU - Grace, Edward G.
AU - Reynolds, Mark A.
AU - Greenspan, Joel D.
N1 - Funding Information:
This study was supported by NIH grants RO1-NS39337 and P50-AR49555. This work constituted part of a PhD dissertation submitted to University of Maryland, Baltimore.
PY - 2004/5
Y1 - 2004/5
N2 - Several studies demonstrate that women are more sensitive to experimental pain than men. In addition, women exhibit greater temporal summation of heat and mechanically evoked pain. Since temporal summation of pain is centrally mediated, its greater expression in women suggests a central nociceptive hyperexcitability relative to men. The purpose of this study was to pursue this theory, by further assessing sex differences in (1) temporal summation of mechanically evoked pain, and (2) aftersensations following repetitive noxious stimulation. Sixteen series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 25 women and 25 age-matched men. The subjects rated the pain intensity and unpleasantness caused by the first, fifth and tenth stimulus in the series, as well as their aftersensations 15 s and 1 min following the end of stimulation. Data were analyzed by three-way repeated-measures analysis of variance. Pain and unpleasantness ratings increased with repetition of stimulation (P<0.0001). Temporal summation of pain intensity and unpleasantness ratings were more pronounced in women than men (P<0.0001). In addition, significant temporal summation occurred only with 2 s interstimulus interval for men (P<0.0005), but with 2 and 5 s interstimulus interval for women (P<0.0001). Moreover, women provided greater ratings for the intensity and the unpleasantness of aftersensations (P<0.0005), and reported painful aftersensations at greater frequency (P<0.05). Greater temporal summation of pain and aftersensations in women suggests that their central processing of nociceptive input may be more easily upregulated into pathological hyperexcitability, possibly accounting for the higher prevalence of various chronic pain conditions among women.
AB - Several studies demonstrate that women are more sensitive to experimental pain than men. In addition, women exhibit greater temporal summation of heat and mechanically evoked pain. Since temporal summation of pain is centrally mediated, its greater expression in women suggests a central nociceptive hyperexcitability relative to men. The purpose of this study was to pursue this theory, by further assessing sex differences in (1) temporal summation of mechanically evoked pain, and (2) aftersensations following repetitive noxious stimulation. Sixteen series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 25 women and 25 age-matched men. The subjects rated the pain intensity and unpleasantness caused by the first, fifth and tenth stimulus in the series, as well as their aftersensations 15 s and 1 min following the end of stimulation. Data were analyzed by three-way repeated-measures analysis of variance. Pain and unpleasantness ratings increased with repetition of stimulation (P<0.0001). Temporal summation of pain intensity and unpleasantness ratings were more pronounced in women than men (P<0.0001). In addition, significant temporal summation occurred only with 2 s interstimulus interval for men (P<0.0005), but with 2 and 5 s interstimulus interval for women (P<0.0001). Moreover, women provided greater ratings for the intensity and the unpleasantness of aftersensations (P<0.0005), and reported painful aftersensations at greater frequency (P<0.05). Greater temporal summation of pain and aftersensations in women suggests that their central processing of nociceptive input may be more easily upregulated into pathological hyperexcitability, possibly accounting for the higher prevalence of various chronic pain conditions among women.
KW - Aftersensations
KW - Gender differences
KW - Mechanical nociception
KW - Temporal summation
KW - Wind-up
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U2 - 10.1016/j.pain.2004.01.019
DO - 10.1016/j.pain.2004.01.019
M3 - Article
C2 - 15082133
AN - SCOPUS:1842786075
SN - 0304-3959
VL - 109
SP - 115
EP - 123
JO - Pain
JF - Pain
IS - 1-2
ER -