Clinical neurophysiology

Lower urinary tract function relies on neural control, the integrity of whi ch is tested by clinical examination and several diagnostic methods, among them clinical neurophysiological tests. These comprise electrophysiologic m ethods of testing conduction through motor and sensory pathways (both perip heral and central), electromyographic methods, and quantitative sensory tes ting. The latter include tests of sensory thresholds for mechanical stimula tion, vibration, temperature, and electrical current; none of the tests las applied to the urogenital area) have as yet proved of definite usefulness in the diagnosis of patients with incontinence. The text also reviews metho ds and findings of electrophysiological tests including EMG, sacral reflexe s, responses recorded from muscle on stimulation of motor pathways (pudenda l nerve, sacral roots, motor cortex), and potentials recorded from sensory pathways (from nerve, roots, and cerebral cortex) after stimulation in the urogenital area. It is stressed that all electrophysiologic tests of conduc tion (terminal latency, motor evoked potentials, sensory evoked potentials, and sacral reflexes) correlate with patency of the respective neural pathw ay, but are not sensitive to partial neural system lesions of axonal type. The EMG signal can be used as an indicator of muscle activity patterns (kin esiological EMG), or can be analysed to reveal signs of muscle denervation by concentric reedle EMG (CNEMG) or signs of motor unit changes after reinn ervation (CNEMG and single fibre EMG [SFEMG]). Clinical neurophysiological testing should be considered only in very selected groups of incontinent pa tients, particularly those with suspected or known involvement of the neuro muscular system. In these, a documentation of and further characterisation of a lesion may be-in selected cases-relevant for therapeutic decisions or prognosis. At the time being, expert opinion classifies CNEMG and recording of the sacral reflex response on stimulation of the dorsal penile/clitoral nerve as optional in patients with involvement of the peripheral neuromusc ular system. Other tests may be of some help in very selected patients. How ever, expert opinion cannot at this point recommend them for clinical pract ice and classifies them as investigational. Experts expect, that clinical n europhysiological tests will prove of further use particularly in research of a) correlations of test results with both the underlying lesion and disturb ed function; b) pathophysiology of different types of incontinence; c) usefulness of tests in clinical practice for better diagnosis and evalua tion of some physiologically based treatment modalities such as pelvic floo r muscle exercises, biofeedback and electrical stimulation; d) usefulness of tests for intraoperative monitoring, e) and that such research will generally further; insight into pathophysiol ogy of lower urinary tract dysfunction.