A Surprising Finding in TMS Research: A Gentler Dose May Work Better

Transcranial Magnetic Stimulation (TMS) uses magnetic pulses to stimulate areas of the brain involved in mood regulation. Traditionally, the strength of these pulses is based on a patient’s motor threshold—the minimum amount of stimulation needed to produce a small, measurable movement in the hand. A commonly used treatment intensity is then set at 120% of that motor threshold.

While this approach has long provided clinicians with a practical way to determine TMS intensity, emerging research suggests that it may not tell the whole story.

In a study of 28 adults bring treated for major depression, researchers used computer modeling to estimate the electric field that actually reaches the targeted area of each patient’s brain. Interestingly, patients who received a lower electric-field strength at the treatment target tended to show greater improvement with this method.

The study also highlighted why individualized dosing may matter. Two patients treated at the same percentage of their motor threshold can still receive different levels of stimulation at the intended brain target because of differences in individual anatomy. Using personalized brain models to guide dosing was reported to be 48% more precise than relying on the traditional motor-threshold approach alone.

These findings point toward a future in which TMS dosing could become increasingly personalized—taking into account not only a patient’s motor threshold, but also how much stimulation actually reaches the targeted brain region. This may ultimately help clinicians deliver a more precise and comfortable treatment for each individual patient.

Want to know if TMS is right for you? Read more about how it works here.