Neurophysiological evaluation in detrusor instability.

Different and complex neuronal systems are involved in the control of continence. Detrusor overactivity has been divided by the International Continence Society into two functional subgroups: a) detrusor instability and b) detrusor hypereflexia. Only in the latter group has neurological damage been shown, but pathophysiological mechanisms are still unknown. In order to complete a full investigation of sensory and motor pathways 12 female patients affected by idiopathic detrusor instability (mean age 60.2 years; range 49-73) and 13 age-matched healthy women were studied. All patients were submitted to a subtracted cistometrogram (CMG), anal sphincter electromyography (EMG) with a bipolar coaxial needle, sacral reflex analysis after stimulation of the dorsal nerve of the clitoris, tibial and pudendal somatosensory evoked potentials, motor evoked potentials after magnetic cortical coil stimulation, and recording from anal sphincter and abductor brevis hallucis muscles. All patients had normal neurophysiological tests, and no significant differences between patients and controls could be seen. Our data confirms the absence of both clinical and subclinical damage of central sensory or motor pathways in detrusor instability; an alteration of suprasegmental mechanisms cannot be excluded.