The study aims to emphasize that the overactive bladder syndrome (OAB) as we know it, needs refinement to select adequate individualized treatments and to improve the treatment outcome. Additionally, to introduce a new assessment method, the experience sampling method (ESM), a digital tool, which is capable of measuring OAB complaints in a real life context, in order to gain insight in the multifactorial character of OAB (1).

Current assessment tools used to assess the OAB symptom complex were evaluated. A search on OAB guidelines and assessment tools was conducted in Pubmed and Google. The collected assessment tools were evaluated with respect to potential biases and restrictions, using the Cochrane handbook collaboration’s ‘Risk of bias’ tool. Then, the new ESM assessment tool (a smartphone app), was compared with the currently used assessment methods.

Biases in assessment tools
An overview of the different types of biases related to current assessment methods in OAB is presented in table 1. The most common biases in the questionnaires were: ecological bias, information bias, confirmation bias, wording bias and social desirability bias. 

Symptom assessment
Not all symptoms of OAB are assessed in the different evaluated diagnostic tools, as schematized in table 2. All symptoms of OAB: urgency, frequency, incontinence and nocturia are measured in 7 of the 12 (58%) evaluated questionnaires. OAB complaints are bothersome urological complaints, but only 33% of the tools measure symptom bother.  Non urological complaints, such as psychiatric complaints, sexuality and the presence of other somatic complaints are evaluated by 3 of the 12 (25%), 6 of the 12 (50%) and 2 of the 12 (<20%) questionnaires, respectively. 

Experience Sampling Method
The ESM has a high risk for selection bias and attrition bias, but little risk for information, confirmation, social desirability or ecological bias. There is a moderate risk for wording bias compared to the retrospective questionnaires and bladder diaries. A urological ESM has the potential to momentarily assess all OAB symptoms included in the ICS definition (2) in context with the occurrence of other symptoms, such as psychological, psychiatric, gastro-intestinal, gynaecological and muscular complaints. Moreover, the individual complaint pattern is assessed in the context of everyday life, including patient’s location, occupation and social contacts at the time of the assessment. Additionally, quality of life, possible limitations in activities and symptom bother are assessed. Satisfaction of therapy is not assessed with the ESM specifically, but ESM can certainly be used to evaluate treatment response.

Numerous assessment tools have been developed to help assess OAB symptoms. The difficulty about most of the currently available assessment tools is that each different tool measures only a small part of OAB (i.e. one symptom), even though recently, there is growing evidence on the multifactorial character (3), including triggers of symptoms and comorbidities.

Today’s retrospective assessment methods are biased, indicating a need for momentary assessment in OAB, that is able to capture the multifactorial character of OAB and pleiotropic presentation of a potential broader but undetected hypersensitivity syndrome. The digital ESM may fulfill this need, and might guide the way to an aetiologically driven classification of OAB.

Leue C, Kruimel J, Vrijens D, Masclee A, van Os J, van Koeveringe G. Functional urological disorders: a sensitized defence response in the bladder-gut-brain axis. Nature Reviews Urology. 2016.
Abrams P, Cardozo L, Fall M, et al. The standardisation of terminology of lower urinary tract function: report from the Standardisation Sub-committee of the International Continence Society. Neurourology and urodynamics. 2002;21(2):167-178.
Altman D, Iliadou AN, Lundholm C, Milsom I, Pedersen NL. Somatic comorbidity in women with overactive bladder syndrome. The Journal of urology. 2016;196(2):473-477.