Mucosal sensory threshold of urinary bladder and urethra measured electrically.

Urodynamic investigation consists of evaluation of detrusor stretch responses, muscle strength and motor activities. The electrosensitivity test is the only method to evaluate mucosal sensory threshold of exteroceptive receptors in urinary bladder and posterior urethra thus checking integrity of sensory reflex arcs. A constant current square wave pulse of 0.5 msec duration and 10 msec interval is used with increasing amplitude from 0 to 25 mA until the patient registers sensation. Skin electrosensitivity is tested to start with, then perception threshold of urinary bladder and posterior urethra is recorded. Sensory deficits after segmental sacral nerve lesions or after peripheral nerve injuries postoperatively can be quantitated in terms of milliamperes. The urgency syndrome in adult women is characterized by a low perception threshold in the posterior urethra (below 1 mA) while the bladder electrosensitivity is within normal range (3--10 mA).