The purpose of this study is to perform a randomized controlled investigation of the effect of surface nerve stimulation on functional daytime incontinence in children with OAB.

Daytime urinary incontinence is common in children. At the age of 7 a prevalence of 2-9 % has been reported. Daytime urinary incontinence is a heterogenic multifactorial illness where the the symptoms has several degrees of severity and can be caused by different mechanisms. Daytime urinary incontinence can be etiologically classified in the rare neurogenic and structural forms and the common functional or idiopathic form (where no neurological or structural cause of the bladder dysfunction can be identified.

The symptom based diagnosis OAB (overactive bladder) is most often used to describe daytime urinary incontinence in children. OAB is defined as a symptom syndrome including urgency with or without urge incontinence in combination with frequency.

When urinary tract infection and neurogenic and structural causes has been excluded the nonpharmacological bladder rehabilitation is first line treatment of OAB. It is expected that approximately 50 % of the children can be relieved of symptoms by this treatment. In the non-responding cases behavioural modifying regimes can be coupled with anticholinergic medication. However, poor compliance of the child or parents, or dose limiting side effects often influences the efficacy of this intervention. Also a considerable number of children experience no or only limited effect from the treatment even though all instructions are complied with. This has let to research into new treatment modalities and the use of low frequency electrical current to inhibit detrusor overactivity in adults has become common. Pilot studies have indicated a significant effect of TENS on urinary incontinence in children with OAB.

Hypothesis:

• Sacral TENS is an effective treatment of urinary incontinence in children with OAB refractory to anticholinergic medication coupled with bladder training and voiding reeducation.

• The acute effect of sacral TENS can be identified by urodynamics

• It is possible to predict the outcome of sacral TENS treatment in these children.

  30 children (age 5-14 years) with functional daytime incontinence refractory to anticholinergic medication coupled with bladder training. The study protocol consists of 1 week of basic home registrations and a 4 day in-patient phase succeeded by a 4 week home training period. The participants will be randomized to treatment with either active or inactive TENS.

Inclusion Criteria:

• Daytime urinary incontinence with at least 1 episode of at least 1 ml per week
• Incontinence refractory to treatment
• Informed consent

Exclusion Criteria:

• Severe diseases of the kidneys or urinary tract besides OAB