The effect of vaginal and cervical self-stimulation on pain thresholds and intensity in women with chronic pain

The purpose of this study was to determine the effect of vaginal self-stimulation (VS-S) and cervical self-stimulation (CS-S) on: chronic pain intensity (CPI), pain detection threshold (PDT), and pain tolerance threshold (PTT); the time course of the induced analgesia; the duration of the effect; whether there was a difference between VS-S and CS-S on the dependent variables; and determine the relationship of other independent variables and the effect of VS-S and CS-S.;It was hypothesized that in women with chronic pelvic, abdominal, or low back pain: VS-S and CS-S would decrease CPI and increase PDT and PTT during stimulation; CS-S would have a significantly greater effect than VS-S; and the effect would outlast stimulation.;Subjects were screened for exclusion criteria prior to being randomly assigned to either VS-S or CS-S for the first experimental session; the alternate method was applied in a second experimental session within two weeks of the first session. The Multidimensional Pain Inventory (MPI), a background data sheet, the Pain-o-Meter (POM), and the Ugo Basile Analgesy meter were used to collect information about CPI, PDT, and PTT. A curved stimulator apparatus was used to self-stimulate the anterior vaginal wall and a straight stimulator was used to self-stimulate the cervix. Subjects continued to record their CPI following each experimental session.;There was no statistically significant CPI change during VS-S or CS-S. In women with visceral pain, CPI increased and PDT and PTT decreased during VS-S. There were significant changes in PDT and PTT during VS-S and CS-S two subjects with somatic pain. There were differences in the response to self-stimulation by the type of somatic pain, inflammatory or non-inflammatory. Although not statistically significant, the effect of VS-S was greater than CS-S on CPI, PDT, and PTT. The effect of both VS-S and CS-S outlasted stimulation.;Although the results must be viewed cautiously based on the small sample size, this study is the first human study to demonstrate a difference in the effect of neurostimulation on analgesia and pain thresholds based on the type of pain, visceral, somatic, inflammatory, or non-inflammatory. Additional research is needed to substantiate this finding.