[Motor evoked potentials of the perineal floor. Preliminary results]

Neuromotor pathways from the brain to the pelvic floor have been poorly documented. The recent development of Motor Evoked Potentials may well fill this gap in our basic knowledge. Our technique consists of transcutaneous stimulation of the motor cortex and sacral roots with a magnetic device while recording the evoked response from the bulbocavernosus muscle and anal sphincter. Cortical stimulation is performed first at rest and then during voluntary contraction of the examined muscles ("facilitation" procedure). Sacral root stimulation is performed at rest. Stimulation at 2 different levels allows measurement of the total transit time (brain to muscle transit time) and the peripheral transit time (sacral roots to muscle). By subtracting the latter from the former, the central transit time (brain to sacral roots) is obtained. The technique is painless, and to our knowledge no side effects have been reported. The authors present the preliminary results of this new technique.