Prediction of the response to repetitive transcranial magnetic stimulation by spectral powers of prefrontal regions of brain.

Introduction: Quantitative assessments of the effects induced by repetitive transcranial magnetic stimulation (rTMS) are crucial to develop more efficient and personalized treatments. Objectives: To determine the spectral powers of different subbands of EEG correlated with treatment response to rTMS.   Materials and Methods: the spectral powers of different subbands of EEG correlated with treatment response to rTMS. Methods: In an open label study 10 patients with intractable major depression received a ten session 20 Hz rTMS over left dorsolateral prefrontal cortex. The EEGs were recorded in all subjects prior and post intervention using a 19-channel EEG system. Hamilton depression rating scale (HAM-D) was also used to determine treatment response. The rTMS protocol consisted of daily one session of 60 trains (2.5 s, inter-train of 17.5 s) at 120% MT for 5 consecutive days per week and 2 weeks. Absolute and relative powers in all electrodes for delta (0-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sensorimotor rhythm (SMR)(12-15 Hz), beta (15-20 HZ), and high beta (20-28 Hz) were compared prior and post intervention in the responders. Spectral powers of prefrontal and sensorimotor regions of brain predict response to repetitive transcranial magnetic stimulation   Results: In the responders (n=5), absolute powers of alpha in F3, F4, C3, and C4 electrodes, absolute power of theta and alpha sub-bands in C4 electrode significantly changed (P<0.05). In the SMR band, absolute powers in the Fp1, Fp2, F3, F4, F7, FZ, C3, and C4 significantly changed (P<0.05). In beta subband, relative power in C4 and absolute power in Fp1, Fp2, F4, CZ, and C4 significantly changed (P < 0.05).   Conclusion: The spectral powers of particular sub-bands in prefrontal cortex and sensorimotor areas can predict response to rTMS treatment.