Neurourology and Urodynamics Intra-Rater Reliability and Diagnostic Accuracy of a New Vaginal Dynamometer to Measure Pelvic Floor Muscle Strength in Women With Urinary Incontinence Georgia Romero-Culler es, 1 * Esteban Pe ~ na-Pitarch, 2 Celia Jan e-Feixas, 1 Anna Arnau, 3 Jesus Montesinos, 3 and Montserrat Abenoza-Guardiola 1 1 Physical Medicine and Rehabilitation, Althaia Xarxa Assistencial Universit aria de Manresa, Manresa, Barcelona, Spain 2 Escola Polit ecnica Superior d’Enginyeria de Manresa (EPSEM), Universitat Polit ecnica de Catalunya, Manresa, Barcelona, Spain 3 Clinical Research Unit, Althaia Xarxa Assistencial Universit aria de Manresa, Manresa, Barcelona, Spain Aims: The first choice treatment in urinary incontinence (UI) is rehabilitation of the pelvic floor in order to improve muscle strength. However, no entirely reliable instruments for quantifying pelvic floor muscle (PFM) strength are currently available. Our aim was to test the intra-rater reliability and diagnostic accuracy of a new vaginal dynamometer for measuring PFM strength. Methods: Test-retest reliability study. One hundred and four women with stress urinary incontinence (SUI) were recruited. Patients were excluded if they had a history consistent with urge urinary incontinence or pelvic organ prolapse, pregnancy, previous urogynecological surgery, severe vaginal atrophy, or neurological conditions. The examination comprised digital palpation quantified by the modified Oxford scale and by two consecutive dynamometry measurements obtained using a new prototype dynamometer. This instrument comprises a speculum in which an inductive displacement sensor (LVDTSM210.10.2.KTmodel, Schreiber) is attached to a spring of known stiffness constant (k). The intraclass correlation coefficient (ICC) was calculated to assess intra-rater reliability. Diagnostic accuracy was assessed using Receiver Operating Characteristics (ROC) curves analysis. Results: Of the 104 subjects included, 59.6% presented scores between 0–2 on the Oxford scale. Intra-rater reliability was 0.98 (95%CI: 0.97– 0.99). In the Bland & Altman plot, the distribution of disagreements was similar in the lowest and the highest strength values. The diagnostic accuracy of the dynamometer with regard to digital palpation showed an area under the curve of 0.85 (95%CI: 0.77–0.93). Conclusions: Our results suggest that this new vaginal dynamometer is a reliable and valid instrument for quantifying PFM strength. Neurourol. Urodynam. # 2015 Wiley Periodicals, Inc. Key words: dynamometer; pelvic floor muscle strength; rehabilitation; urinary incontinence INTRODUCTION The International Continence Society (ICS) defines urinary incontinence (UI) as any involuntary urine leakage. 1 Stress urinary incontinence (SUI) is the most frequent type of UI, defined as involuntary leakage on effort or physical exertion, or upon sneezing or coughing. 2 The prevalence of UI ranges from 14% to 69% and increases with age. More than 50% of patients attending geriatric clinics are incontinent. 3 UI is far more prevalent than other pathologies such as hypertension, depression or diabetes mellitus, and may have a highly negative impact on quality of life, 4 reducing social, personal and sexual relations, 5 and physical activity. 6 Stress urinary incontinence (SUI) appears to result from multiple failures in the continence mechanism, where defects in sphincteric function, 1 pelvic floor muscle (PFM), 2,3 connective tissues, 4 or neural structures 5 may all play a role. Physical therapy, mainly involving strength training of the PFM and training motor control strategies to prevent urine loss, 6–8 has shown positive results in women with SUI. As such, physical therapy has been recommended by the International Conti- nence Society as the first-line treatment for women whose primary complaint is SUI. 8,9 This treatment helps support pelvic organs (urethra, uterus, and bladder), thus avoiding genital prolapse and other dysfunctions of the pelvic floor such as incontinence. 10 At present, the standard instruments for evaluating pelvic floor muscle strength are vaginal palpation and manometry. Vaginal palpation using the modified Oxford grading scale 11 is currently the gold standard, although it is a totally subjective method with low test-retest and inter-rater reliability. 12 Vaginal manometry 13 is not an efficient method for measuring intravaginal pressure, as it must always be performed at the same anatomical level, and taken into account that measure- ments of abdominal pressures can alter the PFM response. 14 The ideal location appears to be the urethra rather than the vagina, with the same baseline pressures, the same units of measurement and the same size and shape of instrument, but these requirements are difficult to achieve. 15 In addition, vaginal manometry evaluates pressure, and is mistakenly identified as an instrument for measuring strength. Some authors suggest assessing PFM strength using prototype vaginal dynamometers, but none are commercially available. Other techniques used to evaluate PFM function include electromyography (EMG), ultrasound, and dynamic magnetic Dr. Fred Milani led the peer-review process as the Associate Editor responsible for the paper. Potential conflicts of interest: Dr. Pe~ na and Dr. Romero report a European patent application number 12765883.9 licensed to OIARSO S. COOP. Grant sponsor: Spanish Government; Grant number: DPI2013-40882-P Correspondence to: Dr. Georgia Romero-Culleres, Physical Medicine and Rehabilitation, Althaia Xarxa Assistencial Universit aria de Manresa, Avinguda Bases de Manresa, 6-8, 08242 Manresa, Barcelona, Spain. E-mail: gromero@althaia.cat Received 23 June 2015; Accepted 16 October 2015 Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/nau.22924 # 2015 Wiley Periodicals, Inc. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by UPCommons. Portal del coneixement obert de la UPC