Aging and overactive bladder may be associated with loss of urethral sensation in women

Aims: To compare current perception thresholds (CPT) in the urethra and bladder of women with idiopathic overactive bladder to asymptomatic controls. Methods: Women with ≥1 urge urinary incontinence (UUI) episode per week on 7-day diary, seeking treatment for UUI underwent CPT testing using a Neurometer® CPT device (Neurotron, Inc., Baltimore, MD). Testing was done in the urethra and bladder at three frequencies 2,000, 250, and 5 Hz corresponding to A-β, A-δ, and C fibers, respectively. CPT values from the women with UUI were compared to CPT values from a group of control women without lower urinary tract symptoms. Results: Forty-eight controls without lower urinary tract symptoms and 13 women with UUI were included in the analysis. Women with UUI were significantly older (mean ± SD age 62 ± 14 and 44 ± 15, P < 0.0005) and more likely to be vaginally parous (P = 0.007) than control women. Urethral CPT at 2,000, 250, and 5 Hz were significantly higher in women with UUI than controls, while bladder CPT were not different between groups. Using logistic regression, to control for age and parity, urethral CPT at 5 Hz remained significantly higher in women with UUI than controls (P = 0.013). Conclusion: Urethral sensation is significantly higher in older women, suggesting sensory neuropathy in the lower urinary tract increases with age and may contribute to the increase in overactive bladder seen with aging. These data reinforce the role of the urethra in lower urinary tract function.