The effects of deep TMS on QEEG power, asymmetry, and coherence metrics in major depressive disorder.

OBJECTIVE: Major depressive disorder (MDD) is one of the most prevalent and debilitating health conditions worldwide; unfortunately, numerous patients are "treatment-resistant" to traditional therapies. Deep transcranial magnetic stimulation (Deep TMS) has emerged as an effective treatment for such cases; however, the precise mechanisms by which Deep TMS alters neurophysiological patterns and attenuates depressive symptoms are still ambiguous. METHODS: In the current study, resting-state quantitative electroencephalography (QEEG) measures of power, coherence, and asymmetry were assessed pre-and-post treatment in a sample of 75 participants with MDD. RESULTS: The 36-session protocol yielded a response rate of 82.6 percent and an overall significant reduction in depressive symptoms. Further, slow-frequency delta activity was reduced in the left prefrontal cortex while frontal beta asymmetry shifted leftward. Coherence (brain connectivity) was also improved between the left prefrontal and temporal lobes. CONCLUSIONS: These findings provide additional support for the utility of Deep TMS in altering aberrant neurophysiological patterns pertaining to depression. SIGNIFICANCE: Deep TMS paired with qEEG should continue to be utilized for the treatment of MDD as well as other treatment-resistant conditions.