A new device for simultaneous measurement of pelvic floor muscle activity and vaginal blood flow: a test in a nonclinical sample.

Introduction: Dyspareunia in women, defined as persistent or recurrent genital pain associated with sexual intercourse, is hypothesized to be related to (fear associated) pelvic floor hyperactivity and to diminished sexual arousal. Psychophysiological research to support these hypotheses is scarce and concentrates mostly on the role of either pelvic floor activity or sexual arousal. To investigate both factors, a measurement device that enables simultaneous assessment of pelvic floor muscle activity and genital sexual arousal would be most optimal.

Aim: The aim of this study was to test a new vaginal device0-a vaginal photoplethysmograph with build-in surface electromyography (EMG)--that allows simultaneous assessment of pelvic floor muscle activity and vaginal blood flow.

Main Outcome Measures: Genital arousal measured as vaginal pulse amplitude (VPA) and vaginal surface EMG.

Methods: Thirty-six sexually functional women participated. To investigate the sensitivity of the device for changes in genital blood flow and involuntary changes in pelvic floor activity, VPA and vaginal surface EMG were monitored during exposure to sexual and anxiety-evoking film clips. In addition, vaginal surface EMG was monitored during voluntary flick and hold contractions.

Results: VPA increased in response to the sexual film, and EMG values were significantly higher in response to the anxiety-evoking film. Higher EMG values in response to the anxiety film were associated with lower VPA. EMG during the instructed 3-second hold pelvic floor contractions showed, as expected, higher values during pelvic floor contractions with support of surrounding muscle groups, compared with pelvic floor muscles alone.

Conclusion: The device is sensitive to changes in vaginal blood flow in response to sexual stimuli, and it is able to pick up small, involuntary changes in pelvic floor activity associated with anxiety. Also, the device is able to record changes in pelvic floor activity during voluntary pelvic floor contractions. This new device will be a valuable tool in further research on superficial dyspareunia.