A switched system for modeling the +-inal dilation exercises

Genito-pelvic pain/penetration disorders, i.e., painful experiences during penetrative sexual intercourse, affect an estimated 30-40% of people with vaginas at some point in their lives. Treatments for Genito-pelvic pain/penetration disorders vary depending on the main cause of the condition but may include the use of vaginal trainers/dilators which are used to stretch the vaginal duct and relax the Pelvic floor muscles. As a step towards understanding how patients respond to vaginal trainers, we investigate the interaction of pain and pleasure characteristics during treatments. In this paper, we adapt an existing qualitative model into a switched system where switches are determined by a patient's subjective level of pleasure. A qualitative model of the pain and fear characteristics is derived for each switched state. Due to sparsity in the experimental data, we adopt a weighted least squares approach for parameter identification using online (constant sampling period) and offline data (sparse and inconsistent sampling). The results indicate that it is a promising method compared to the grey-box model without considering pleasure levels but there is an obvious and variable delay in the reporting of a patient's pleasure levels which affects the overall performance of the switched system.