Objectives. To evaluate the usefulness of electrical stimulation for urinary incontinence due to detrusor overactivity in a randomized, double-blind manner.

Methods. Sixty-eight patients (29 men, 39 women, 70.0 ± 11.2 years) were studied. Detrusor overactivity was urodynamically defined as involuntary detrusor contractions of more than 15 cm H₂O during the filling phase. Ten-hertz square waves of 1-ms pulse duration were used. A vaginal electrode was used in the women and an anal or surface electrode in the men. The stimulation was given for 15 minutes twice daily for 4 weeks. The efficacy was evaluated on the basis of a frequency/volume chart and urodynamic study before and after treatment.

Results. Thirty-two patients in the active group and 28 in the sham group completed the study. The patient impressions were very good or good in 59% and 39% of the active and the sham group, respectively (P = 0.0354). On the cystometrogram, the bladder capacity at the first desire to void and the maximum desire to void increased significantly (P = 0.0104 and P = 0.0046, respectively) in the active group, but not in the sham group. Seven patients in the active group and 1 patient in the sham group were cured (P = 0.0324); 26 patients (81.3%) in the active group and 9 (32.1%) in the sham group improved (P = 0.0001). Of 17 patients in the active group, 13 remained cured or improved for an average of 8.4 months after completion of the 4-week treatment; in the sham group, 3 of 6 patients were cured or improved for an average of 4.7 months after completion of the 4-week treatment.

Conclusions. Electrical stimulation was useful in treating urinary incontinence due to detrusor overactivity.