['Standard urodynamic investigations showed no correlation between the efficacy of sacral neuromodulation (SNS) and urodynamic data. Ambulant urodynamic investigations (ACM) are presented as more sensitive and reliable in detecting and quantifying bladder overactivity. In this study we looked at the correlation and results of ambulant urodynamic data and the clinical effects of SNS.', 'Data of patients with bladder overactivity, who underwent an ACM before and during SNS were investigated. Blind analyses of the ACM were performed and the detrusor activity index (DAI) was calculated as the degree of bladder overactivity of the detrusor. The ACM parameters, before and during SNS, were analyzed and correlated to the clinical effect of SNS.', 'In 22 of the 34 patients a DAI before and during stimulation could be calculated because of quality aspects. In all other patients, the other ambulatory urodynamic parameters could be analyzed and a significant reduction was found in bladder overactivity. A significant correlation (p = 0.03) was found in DAI reduction of the ACM before and during SNS as compared to the clinical improvement in overactive bladder symptoms.'] Do urodynamic results of sacral neuromodulation correlate with subjective improvement in patients with an overactive bladder?