Overactive Bladder Is Not Only Overactive but Also Hypersensitive

Objectives

To evaluate differences in bladder filling sensations and current perception threshold (CPT) values between patients with and without overactive bladder (OAB), and to further investigate the correlation between CPT values and voiding patterns in OAB patients.

Methods

Detrusor overactivity and bladder volumes at first sensation of bladder filling, first desire to void, and strong desire to void during filling cystometry were compared between 55 female patients with OAB and 42 with non-OAB. CPT measurements from the bladder mucosa taken after neuroselective electrostimulation at frequencies of 2000, 250, and 5 Hz were compared between the 2 groups. In OAB patients, the correlations between CPT values and voiding variables based on 3-day bladder diaries were investigated.

Results

OAB patients showed significantly more detrusor overactivity than non-OAB patients (P <.05). Bladder volumes at first sensation of bladder filling, first desire to void, and strong desire to void were significantly lower in OAB patients than in non-OAB patients (P <.05). CPT values at all 3 frequencies were also significantly lower in OAB patients (P <.05). The total number of urgency episodes correlated with CPT values at 250 (r = −0.274, P = .045) and 5 Hz (r = −0.293, P = .032). The total number of urge incontinence episodes also correlated with CPT values at 250 (r = −0.279, P = .041) and 5 Hz (r = −0.272, P = .046).

Conclusions

Bladder sensory profiles displayed a more sensitive bladder in OAB patients compared with non-OAB subjects. OAB patients may have bladders that are not only overactive, but also hypersensitive.