Effect of alarm therapy on conditioning of central reflex control in nocturnal enuresis: pilot study on changes in prepulse inhibition (PPI)

Abstract

Alarm therapy is a long-established first-line therapy for nocturnal enuresis (NE). Desamino-arginine vasopressin (dDAVP) as alternative first-line therapy was shown to increase the prepulse inhibition (PPI) of startle reflexes, thus supporting the hypothesis of a maturational delay of reflex inhibition in NE. Effects of alarm therapy on PPI have not yet been investigated. The PPI of startle reflexes was measured in 20 children with NE (13 boys, 7 girls, median age 8.5 years, range 5-13) before and after at least 6 weeks of alarm treatment and compared with repeated PPI measurements in 11 healthy controls (7 boys, 4 girls, median age 8 years, range 6-13). In the NE patients, PPI increased from a median baseline of 20-46% under alarm therapy (p = 0.005), with a reduction from a median of 7 to 2 wet nights per week (p = 0.002). The controls showed no difference in PPI (52% median at first, 40% at second measurement, p = 0.966). The increase of PPI trough alarm therapy was comparable with that under dDAVP, suggesting an analogous method of action and explaining the alternative or synergistic effect of both therapies. In addition, it further substantiates the hypothesis of a maturational delay of reflex control in NE.