What is the Nature of Pelvic Floor Muscle Involvement in Dyspareunia?

Summary

Dyspareunia, or pain experienced by women during penetrative sexual activities, affects the psychological and sexual health of more than one in five Canadian women \[1\], yet its pathophysiology is poorly understood \[2-4\] and evidence for management approaches is limited.\[5\] It is thought that pelvic floor muscle (PFM) dysfunction is implicated in many forms of dyspareunia, while the nature and aetiology of this involvement remain largely unknown. The goal of this study is to understand if and how PFM dysfunction contributes to the pain experienced by women with provoked vestibulodynia (PVD), the most common cause of dyspareunia. This goal will be achieved through implementing an innovative and comprehensive approach to measuring the neuromuscular function of the PFMs. Understanding the pathophysiology of PVD is essential to the development of effective interventions to improve the health and quality of life of the many Canadian women who suffer from dyspareunia.

Conditions

• Dyspareunia

Interventions

DIAGNOSTIC_TEST

Corticomotor excitability to the pelvic floor muscles

Transcranial magenetic stimulation will be used to probe the excitability of cortical projections to the pelvic floor muscles. The outcomes of interest will include motor evoked potential amplitude and silent period.

DIAGNOSTIC_TEST

Pelvic floor muscle response to pressure applied at the vulvar vestibule

Electromyography will be used to determine whether the pelvic floor muscles (PFMs) respond to pressure applied to the vulvar vestibule as anticipatory (i.e. PFMs are active before the pressure is applied) and as behavioural (i.e. PFMs are active after the pressure is applied) responses. The amplitude of the EMG responses will also be recorded.

DIAGNOSTIC_TEST

Pressure pain threshold (PPS)

A custom vulvalgesiometer will be used to determine the mean pressure at which participants first report pain at the posterior vaginal fourchette.

DIAGNOSTIC_TEST

Temporal summation of pain

A custom vulvalgesiometer will be used to apply the same pressure (rated as 4/10 duiring PPS testing as described above) to the vulvar vestibule across 10 repetitions. The difference in pain rated on the tenth application and that rated on the first application will be the outcome.

DIAGNOSTIC_TEST

Tonic, phasic and reflex activation of the pelvic floor muscles (PFMs)

Electromyography will be used to measure the mean smoothed, rectified activation amplitude across 1 second of complete rest, across three maximal effort PFM contractions, and across three attempts at a bearing down maneuver.

Sponsors & Collaborators

• University of Ottawa

  lead OTHER

Principal Investigators

• Linda McLean · University of Ottawa

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-02-02

Primary Completion

2023-01-15

Completion

2023-03-20

Countries

• Canada

Study Locations