THE RELATIONSHIP BETWEEN PSYCHOSOCIAL FUNCTIONING AND DIFFUSE NOXIOUS INHIBITORY CONTROL FUNCTION IN WOMEN WITH PROVOKED VESTIBULODYNIA AND PAIN FREE CONTROLS
Sutton, Katherine Stella
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Provoked Vestibulodynia (PVD) is the most common form of chronic vulvar pain, affecting 12% of women in the general population. PVD is characterized by a severe burning pain in response to pressure localized to the vaginal entrance. Research examining the pain component of PVD indicates that it has much in common with other chronic pain conditions. Increased pain sensitivity has been demonstrated in other chronic pain conditions to be due in part to impairment in centrally acting endogenous pain modulation systems, such as Diffuse Noxious Inhibitory Control (DNIC). DNIC is triggered by the simultaneous application of two painful stimuli, with pain at one body site inhibiting pain at another body site. Because DNIC consists of a feedback loop that involves the spinal cord and the brain, it is thought to be dependent upon both sensory and affective pain components. In the current study, 20 women with PVD and 24 controls underwent sensory testing to determine the integrity of DNIC function. Unexpectedly, women with PVD displayed a DNIC response of greater magnitude than controls. Participants also completed measures to assess the interplay between group, DNIC, and psychosocial functioning. Women with PVD experienced decreases in psychosocial functioning; however, this reduction was not found to mediate the relationship between group and DNIC function. Findings of intact DNIC function in women with PVD do not imply that PVD is not a chronic pain condition. DNIC is a complex and dynamic process and warrants further study using different stimuli and paradigms. This study supports previous literature, while adding to the development of a greater understanding of the interaction between psychophysical and psychosocial components of chronic pain, which will allow for the creation of better assessment and treatment strategies.