Simultaneous measurement of pelvic floor muscle activity and vaginal blood flow: a pilot study

Dyspareunia, defined as persistent or recurrent genital pain associated with sexual intercourse, is hypothesized to be related to pelvic floor hyperactivity and to diminished sexual arousal. Empirical research to support these hypotheses is scarce and concentrates mostly on the role of either pelvic floor activity or genital arousal in female dyspareunia. Currently, however, there is no measurement device to assess pelvic floor activity and genital response simultaneously.

The aim of this study was to investigate the validity of a new device that enables simultaneous measurement of pelvic floor activity and genital response in women.

Genital arousal measured as vaginal pulse amplitude, and vaginal surface electromyogram (EMG).

Thirty sexually functional women participated. To investigate the accuracy of genital response measurement with the adapted photoplethysmograph, and the sensitivity of the device for involuntary changes in pelvic floor activity, vaginal pulse amplitude and vaginal surface EMG were monitored during exposure to emotional, including erotic, films. In addition, vaginal surface EMG was monitored during instructed pelvic floor contractions.

The genital data obtained during emotional films proved accurate measurement of genital response. EMG values during the emotional films indicated limited sensitivity of the device for small, involuntary changes in pelvic floor activity due to emotional state. The EMG measurements during the instructed pelvic floor contractions proved sensitivity of the new probe to voluntary pelvic floor activity.

It is concluded that following improvement of the sensitivity of the EMG measurement for small, involuntary changes in pelvic floor activity, the device will be a valuable tool in research on superficial dyspareunia.