The Latest Evolution of Repetitive TMS for Treatment-Resistant Depression

At the American Psychiatric Association 2023 Annual Meeting, Nolan Williams, MD, presented as part of a session titled “Advances in Non-Invasive Neuromodulation: Exploring rTMS and SAINT for the Treatment of Psychiatric Disorders.” His portion of the session focused on a novel approach to repetitive transcranial magnetic stimulation (rTMS) for patients with treatment-resistant depression (TRD).

Dr. Williams briefly defined rTMS, which is a neuromodulation technique that has been shown to produce a significant reduction in TRD symptoms after 20 to 30 daily sessions of repeated magnetic pulses delivered to the left prefrontal cortex. Subsequent meta-analysis found that rTMS was significantly more effective than sham treatment for reducing symptoms of depression.

Dr. Williams then described a new approach to neuromodulation, Stanford Accelerated Intelligent Neuromodulation Therapy, or SAINT. SAINT combines advanced imaging techniques, machine learning, and targeted rTMS to personalize, increase the speed of, and, according to Dr. Williams, potentially improve treatment for individuals with TRD.

Dr. Williams explained that functional magnetic resonance imaging or some other imaging technology was used to identify specific areas of the brain that are dysfunctional. Then, rTMS, using a rapid theta stimulation pattern, is directed based on the individual patient’s brain activity.

Dr. Williams compared his team’s work in improving rTMS with the early evolutions in communication technology. He likened rTMS to Morse code, where the information is a direct signal bypassing the sensory systems. In that respect, the researchers’ goal was to find a way to deliver a more “biologically relevant signal,” or, to continue the Morse code analogy, a message that was in the right language and directed to the right recipient.

Dr. Williams also briefly noted that rTMS, like many other therapies in psychiatry, was stumbled upon by accident. The development of magnetic brain stimulation was originally pursued as replacement for electrical stimulation in probing brain behaviors.

Overall, Dr. Williams suggested that rTMS technology and evolutions like SAINT give psychiatrists the ability to affect the brain in the same way that neurosurgeons have for years, with direct electrical stimulation during epilepsy surgery, but non-invasively and potentially selectively.