Device/Equipment Drug Medical Surgery Test Other Effective Date: 3/17/2012 Policy Last Updated: 5/15/2012

Prospective review is recommended/required. Please check the member agreement for preauthorization guidelines. Prospective review is not required. Description: Transcranial magnetic stimulation (TMS also called repetitive transcranial magnetic stimulation [rTMS]) is a non-invasive method of delivering electrical stimulation to the brain. A magnetic field is delivered through the skull where it induces electric currents that affect neuronal function. Repetitive TMS is being evaluated as a treatment of depression and other psychiatric/neurologic brain disorders. Transcranial magnetic stimulation (TMS) was first introduced in 1985 as a new method of non-invasive stimulation of the brain. The technique involves placement of a small coil over the scalp; passing a rapidly alternating current through the coil wire, which produces a magnetic field that passes unimpeded through the scalp and bone, resulting in electrical stimulation of the cortex. TMS was initially used to investigate nerve conduction; for example, TMS over the motor cortex will produce a contralateral muscular-evoked potential. The motor threshold, which is th