When TMS Therapy Is Not Appropriate

Transcranial magnetic stimulation (TMS) is a brain stimulation technique that is not as new as some people believe it to be. It has been a treatment option for depression since the mid-80s. Psychiatrists may use TMS as a standalone treatment or as part of a larger treatment plan. Some mental health practitioners use brain stimulation to complement psychotherapy or medication.

Magnetic brain stimulation can also treat neurological conditions like stroke paralysis and chronic pain. Physicians will use the treatment to improve the efficacy of a more extensive treatment plan.

How TMS improves neurological function

It may be helpful to think of the nervous system as the body’s electrical wiring, transmitting signals that keep the body operational. This means that the targeted application of a magnetic field to this "wiring" will have an effect on it. With TMS, the effect is an increase in neural activity and the release of beneficial neurotransmitters. Here is how it works:

• A physician or psychiatrist screens and clears their patient for the procedure
• They work out where to target the magnetic energy from the TMS equipment
• The doctor/psychiatrist determines the strength of the magnetic field that will be most effective for their patient
• Next, the patient will wear earplugs to block out the noise from the TMS machinery
• The doctor places a magnetic coil on the scalp, directly above a specific location on the prefrontal cortex
• They set the intensity and frequency of the magnetic pulse before starting the TMS machinery

The TMS machinery converts electrical energy from a power source to a magnetic field around the coil. This magnetic energy travels two to three centimeters into the section of brain tissue directly under the coil. In the process, the magnetic field induces small electric currents that activate the nerve cells.

The ideal candidate for TMS

Psychiatrists often recommend TMS as a therapy for treatment-resistant depression and anxiety. TMS can also help with neurological disorders as a part of a larger treatment plan. In both cases, the patient should be at least 18 years old. A good candidate for TMS should also be free of risk factors that could result in a bad reaction to treatment.

When TMS therapy is not an option

For certain risk factors, brain stimulation has the potential to do more harm than good. Doctors will avoid exciting the nervous system of patients with the following conditions.

1. A history of seizures

People who have epilepsy and similar conditions get seizures because of a spike in neural activity. Increasing the level of neural activity in such patients could trigger a seizure, which is a bad outcome.

2. Medical implants

Magnets will affect medical implants with metal in them. They can dislocate, heat, or otherwise damage the implant.

This means that TMS therapy can be harmful to people with pacemakers or a defibrillator implant. That said, a doctor may consider TMS if the implant in question is at least 12 inches from the magnetic coil that will be used.