This study sought to provide a preliminary assessment of whether spinally mediated afferent hyperactivity (i.e., central sensitization) might contribute to manifestations of overactive bladder syndrome (OAB) in women as indexed by elevated temporal summation of evoked heat pain stimuli.
We recruited 20 adult women with OAB who were planning to undergo interventional therapy for OAB with either onabotulinumtoxinA injection or sacral neuromodulation and 23 healthy controls without OAB symptoms to undergo quantitative sensory testing with cutaneous thermal pain temporal summation. The primary study outcome was the degree of temporal summation, as reflected in the magnitude of positive slope of the line fitted to the series of 10 stimuli at the 49°C target temperatures. Linear regression and analysis of covariance were utilized to compare the degree of temporal summation between study groups.
The standardized slope of temporal summation trials for women with OAB was significantly higher than for controls (β = 3.43, 95% confidence interval = 0.6-6.2, P = 0.017). The adjusted means ±SE of the standardized temporal summation slopes for the full OAB and control groups were 3.0 ± 0.5 (95% confidence interval = 2.0, 4.1) and 1.7 ± 0.5 (95% confidence interval = 0.7, 2.7), respectively.
In this preliminary study, we demonstrated that women with OAB refractory to primary and secondary therapies exhibited greater thermal cutaneous temporal summation than women without OAB symptoms. This suggests that central sensitization, indexed by temporal summation, may be an underlying factor contributing to OAB in some women. Neurourol. Urodynam. © 2016 Wiley Periodicals, Inc.
Neurourology and urodynamics. 2016 Jul 19 [Epub ahead of print]
William Stuart Reynolds, Elizabeth Timbrook Brown, Jill Danford, Melissa Kaufman, Alan Wein, Roger Dmochowski, Stephen Bruehl
Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee., Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee., Department of Obstetrics and Gynecology, Vanderbilt University Medical Center, Nashville, Tennessee., Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee., Division of Urology, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania., Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee., Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.