Fig. 1. Photo of transcranial magnetic stimulation (TMS) motor threshold assessment in the postanesthesia care unit. Dr. Weinstein ( left ) supports the patient's right wrist to allow free movement of thumb and fingers, which are moved via TMS stimulation of the corresponding area of the patient's motor cortex. Dr. Borckardt ( middle ) positions the coil over the motor cortex and locates the area corresponding with abductor pollicis brevis (APB). Neil Shelly ( right ) runs the Parameter Estimation by Sequential Testing (PEST) algorithm software and adjusts the TMS machine output to the specified levels until the amount of TMS output is determined that is necessary to cause visible thumb movement 50% of the time. The subject's face has been blurred to protect confidentiality.