Pain
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Comparative Study
Sex differences in perceived pain are affected by an anxious brain.
Decades of research confirm that women have greater pain sensitivity than men. Women also show greater overall anxiety sensitivity than men. Given these differences, we hypothesized that sex differences in anxiety would explain sex differences in experienced pain and physiological responses to pain (at both spinal and cortical levels). ⋯ This means that stable predispositions to respond with heightened apprehension contribute to baseline pain sensitivity differences between the sexes. These results indicate that the modulatory effect of affect on pain-related brain processes may explain why men and women experience painful shocks so differently. In our study, the mediating role of anxiety on sex differences in pain was tested and confirmed using path analysis.
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Randomized Controlled Trial Comparative Study
The effects of total and REM sleep deprivation on laser-evoked potential threshold and pain perception.
We investigated the effects of total and rapid eye movement (REM) sleep deprivation on the thermal nociceptive threshold and pain perception using the objective laser-evoked potential (LEP) and the subjective visual analogue scale (VAS). Twenty-eight male adult volunteers were assigned into Control (CTRL), Total (T-SD), and REM (REM-SD) Sleep Deprivation groups. The T-SD and REM-SD volunteers were totally or selectively deprived of sleep for 2 and 4 consecutive nights, respectively. ⋯ No significant variations were observed in the REM-SD group, suggesting a predominant role for slow wave sleep rather than selective REM-SD in pain perception. Also, for both sleep-deprived groups, the mean values of the LEP threshold and VAS ratings showed a gradual increase that was proportional to the SD deprivation time, followed by a decrease after 1 night of sleep restoration. These findings demonstrate a hyperalgesic modification to pain perception (as reflected by the augmented VAS) and a concomitant increase in the LEP threshold following T-SD, an apparently contradictory effect that can be explained by differences in the ways that attention affects these pain measurements.