rTMS versus TMS

A TMS coil can deliver a single pulse, a pair of pulses, or a long train of pulses. Single and paired pulses are mostly used for measurement and research. The clearest everyday example is the motor threshold test at the start of your course: single pulses over the motor cortex until your thumb twitches, which tells the clinician how strong your pulses need to be.

Repetitive TMS delivers pulses in a set rhythm, in trains, for a planned number of pulses per session. Repeating the stimulation is what produces a lasting change in the activity of the circuit being treated, which is why treatment always means rTMS, and why it takes a course of sessions rather than a single visit.

Your psychiatrist chooses the protocol. The ones most used for depression are:

• High-frequency rTMS to the left prefrontal cortex, typically around ten pulses a second in short trains with rests between them. This is the longest established protocol and the standard course at Neuro Evolution.
• Low-frequency rTMS to the right prefrontal cortex, about one pulse a second, which quietens rather than activates and is sometimes used where high-frequency stimulation is not suitable.
• Theta burst stimulation, a newer patterned form that delivers bursts of pulses in a few minutes rather than twenty. It is supported by published trials and may be offered where it fits the clinical picture.

Medicare’s rTMS items cover these forms of treatment when prescribed by a psychiatrist for treatment-resistant depression. “Deep TMS” refers to a different coil design that reaches somewhat further into the brain; it is one variant of rTMS rather than a different treatment, and it is not what we use.

On this website, and in conversation at the clinic, TMS and rTMS mean the same thing: a course of repetitive magnetic stimulation prescribed by a psychiatrist. Which protocol you receive, how many pulses a session, and how many sessions a week are settled at your assessment and written into your treatment plan.