Automatic analysis of urethral electromyography for accurate diagnosis of voiding dysfunction.

An electromyogram contains much more information than observed in the gross pattern of an electromyogram simultaneously recorded with a cystometrogram. Being able to pick up some of the information would be helpful in the accurate diagnosis of ambiguous patients showing a discrepancy between clinical symptoms and laboratory data. This study analyzed electromyograms of the urethral and anal sphincter during the filling phase of the cystometrogram by means of automatic turns-amplitude analysis with a computer-assisted analyzer. In normal subjects, turns and amplitudes of an urethral electromyogram had increased frequency and size as the subjects felt a greater sensation of fullness. In patients with abnormal vesical function, the characteristics of the urethral electromyogram varied. Some of the patients with normal vesical activity and coordinated urethral sphincter, though their clinical symptoms strongly suggested neuropathic vesical dysfunction, showed a low frequency and low amplitude pattern of the urethral sphincter electromyogram. Anal sphincter electromyogram did not always show the same patterns as the urethral sphincter even in the normal subjects. The turns-amplitude analysis of urethral sphincter electromyogram will be of use for accurate diagnosis of vesical dysfunction.