Condition category
Urological and Genital Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Urinary leakage is a common and often distressing problem for women. There is good evidence that pelvic floor muscle exercises can cure or reduce leakage but it is unclear as to how intensely these exercises need to be undertaken. Sometimes a technique called 'electromyography' (EMG) biofeedback is used to help a woman perform the exercises. However, it is uncertain whether using this technique makes the exercises more effective. This study aims to find out whether doing pelvic floor muscle exercises with biofeedback is any more effective than doing exercises without biofeedback.

Who can participate?
Women 18 years of age or above, presenting with a new episode of stress or mixed urinary incontinence (UI).

What does the study involve?
All participants will be asked to attend 6 appointments over 16 weeks with a continence physiotherapist or nurse. At the first scheduled appointment the continence physiotherapist or nurse will ask some questions, look at the participant's bladder diary (which will have been sent to them in advance), and a routine vaginal assessment will be undertaken. If they are eligible and interested in the study then a Researcher will give them information about the study and answer any questions they may have. Providing the woman is still interested they will be given a consent form and a questionnaire to complete, after which they will be randomly allocated to one of two groups. Participants in one group will be taught how to do pelvic floor muscle exercises and will be given a home exercise programme. Participants in the other group will, in addition, receive EMG biofeedback at clinic and will be provided with a small handheld EMG biofeedback unit to help with undertaking the exercises at home. The EMG biofeedback uses a vaginal device called a Periform which in the clinic is connected to a computer screen that displays the contraction of the muscles as a line graph. At the next and subsequent appointments the continence physiotherapist or nurse will assess their condition and discuss their treatment goals and exercise plan. They will educate the participant on how to do pelvic floor muscle exercises. The continence physiotherapist or nurse will discuss possible reasons for their urinary leakage and lifestyle changes they may be able to make which could also help. During these appointments their progress will be monitored and exercise plan adjusted accordingly. Some treatment appointments may be audio recorded to find out if the treatment is being delivered as intended. A small number of women will also be interviewed. A separate Information Leaflet will be given to those selected for Interview. Questionnaires will be sent to the participant for completion at 6, 12 and 24 months into the study. They will also be asked to attend for a follow-up vaginal assessment at 6 months. They will be asked to complete a bladder diary over 3 days at the start and end of the study. This will involve keeping a record of liquids they drink, the number of times they go to the toilet or have an accident and how much urine they pass.

What are the possible benefits and risks of participating?
We do not anticipate any risks from being involved in the study. All the materials and techniques are already being used in the NHS. Participation in the study is therefore only to help us evaluate these procedures and should not involve any additional risk. Some people may feel uncomfortable with vaginal examinations but these would be undertaken as part of routine care. Should the participant decide that this is something they do not wish to have, this will be respected, although they will not be able to take part in the study. This will also not affect the treatment they will receive. Some of the questions may seem invasive but the information is important to us.

Where is the study run from?
The research is being carried out by a group of experienced doctors, nurses, physiotherapists and
researchers from a number of different organisations:
1. Nursing, Midwifery and Allied Health Professions Research Unit, Glasgow Caledonian
University (lead organisation)
2. The University of Stirling
3. Health Services Research Unit, University of Aberdeen
4. Centre for Healthcare Randomised Trials, University of Aberdeen
5. The University of Exeter
6. The University of Otago, New Zealand
7. NHS Greater Glasgow & Clyde
8. NHS Grampian
9. NHS Ayrshire and Arran
The Trial Office is located in the NMAHP Research Unit, Glasgow Caledonian University. The Clinical Trials Unit involved with the trial (CHaRT) is based at the University of Aberdeen. The qualitative researchers are based at University of Stirling.

When is the study starting and how long is it expected to run for?
The study started in September 2013 and will run until May 2018. Participant recruitment is due to start in February 2014.

Who is funding the study?
The study is funded by the National Institute for Health Research, UK.

Who is the main contact?
Professor Suzanne Hagen (Chief Investigator)
Susan Stratton, OPAL Trial Manager

Trial website

Contact information



Primary contact

Prof Suzanne Hagen


Contact details

Dept of Psychology
Glasgow Caledonian University
City Campus
70 Cowcaddens Road
G4 0BA
United Kingdom

Additional identifiers

EudraCT number

N/A number


Protocol/serial number

HTA 11/71/03, 15841

Study information

Scientific title

OPAL: a multicentre randomised trial of the effectiveness and cost-effectiveness of basic versus biofeedback-mediated intensive pelvic floor muscle training for female stress or mixed urinary incontinence



Study hypothesis

The research objective is to compare two types of pelvic floor muscle training (PFMT), basic and intensive, and establish if intensive PFMT (PFMT with the addition of biofeedback) is more clinically effective and cost-effective after 24 months at reducing incontinence, improving quality of life, reducing need for surgery and other incontinence treatments, improving pelvic floor muscle function and increasing women's confidence and adherence to PFMT

More details can be found at: and
Study protocol can be found at:

Ethics approval

West of Scotland Research Ethics Service, 13/03/2013, ref: 13/WS/0048

Study design

Randomised; Interventional and Observational; Design type: Treatment, Qualitative

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Female stress or mixed urinary incontinence


1. PFMT intensified with use of electromyography biofeedback both at home and in clinic.
2. Basic PFMT.

Both groups will be seen for six appointments and intervention over a 16 week period. Follow up, with questionnaires at 6,12 & 24 months and interviews for a sub-group of approximately 40 women.

Assessors carrying out the 6-month pelvic floor muscle assessment will be blinded to which group the woman is in.

Intervention type



Not Applicable

Drug names

Primary outcome measure

International Consultation on Incontinence short form questionnaire (ICIQ-UI SF) measured at baseline, 6, 12 and 24 months

Secondary outcome measures

Urinary outcomes
1. Number of episodes of UI per day, recorded by women in a bladder diary [Locher et al 2001]
2. Impression of global improvement in UI (PGI-I) [Yalcin and Bump 2003]
3. Number of women with UI cured and number with UI improved, derived from the ICIQ-UI ShortForm (cured is a negative response to both 'how often do you leak urine?' and 'how much urine do you usually leak (whether you wear protection or not)?'
4. Uptake of surgery for UI
5. Uptake of other treatment for UI
6. Other urinary symptoms (ICIQ-FLUTS) [Brookes et al 2004]

Quality of life outcomes
1. UI-specific quality of life (Kings Health Questionnaire) [Kelleher et al 1997]
2. General health (EQ-5D-3L) [EuroQol Group]

Pelvic floor related outcomes
1. Prolapse symptoms (POP-SS - Hagen et al 2009)
2. Bowel symptoms (early version of ICIQ Bowel Short Form)
3. Pelvic floor muscle function (Oxford scale - Laycock 2008, ICS method - Messelink et al 2005)
4. Self-efficacy for PFMT (PFME self-efficacy scale) [Chen 2004]
5. Adherence to PFMT (exercise diary/follow-up questionnaire)

Economic outcomes
1. Cost and use of NHS services
2. Cost to the women and their families/carers
3. The incremental costs, QALYs and incremental cost per QALY derived by the economic model.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Women 18 years of age or above, presenting with a new episode of stress or mixed urinary incontinence (UI)
2. Who are willing and eligible to be randomised

Participant type


Age group




Target number of participants

Planned Sample Size: 600

Total final enrolment


Participant exclusion criteria

1. Women who have urge UI alone
2. Women who cannot contract their pelvic floor muscles
3. Women who had formal instruction in PFMT in the last three years
4. Women who are pregnant or less than one year postnatal
5. Women who have prolapse greater than stage II, who have pelvic cancer, cognitive impairment or neurological disease

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Glasgow Caledonian University
G4 0BA
United Kingdom

Sponsor information


Glasgow Caledonian University (UK)

Sponsor details

Dept of Psychology
City Campus
70 Cowcaddens Road
G4 0BA
United Kingdom

Sponsor type




Funder type


Funder name

NIHR Health Technology Assessment (HTA) (UK) 11/71/03

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

2019 results presented at the International Continence Society conference in August 2019 (added 11/05/2020)

Intention to publish date


Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2019 protocol in
2019 protocol in:
2020 results in (added 22/10/2020)
2020 results in (added 10/12/2020)

Publication citations

Additional files

Editorial Notes

10/12/2020: Publication reference added. 22/10/2020: Publication reference and total final enrolment number added. 11/05/2020: The following changes have been made: 1. The intention to publish date has been changed from 30/11/2019 to 30/06/2020. 2. A conference abstract reference has been added. 25/02/2020: Publication reference added. 06/11/2019: Internal review. 21/02/2019: Publication reference added. 13/07/2018: The following changes have been made to the trial record: 1. The trial end date was changed from 31/05/2018 to 30/11/2018 2. The intention to publish date was changed from 01/12/2018 to 30/11/2019