Abstract Aim: Monosymptomatic enuresis (ME) is a common disorder in children with serious social and psychological consequences. Treatment is usually initiated with desamino‐arginine vasopressin (dDAVP) and/or alarm therapy
as first‐line treatment and imipramine as second‐line. All treatments have proven efficacy, but are not successful with all patients. Therefore, a differentiation into subgroups according to treatment efficacy would be beneficial. Methods: A group of patients
resistant to first‐line treatment was treated with imipramine and compared with matched controls successfully treated with dDAVP and/or alarm therapy. Prepulse inhibition (PPI) to acoustic startle reflexes was measured in all patients. Results: In a group of 23 nonresponders,
the median PPI was 72% (range 43–94%) compared with the matched dDAVP/alarm – responders with a median PPI of 26% (range 0–61%) (p < 0.0001). The response rate to imipramine was 87%. Conclusion: The presented data provide evidence that PPI allows
to identify two subgroups of ME. The results offer further insight into (at least) two different pathomechanisms involved in ME: (i) a maturational delay of reflex inhibition with reduced PPI and (ii) a normal PPI, possibly with abnormal sleep patterns, that can be influenced by imipramine.