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Journal of ECT:
doi: 10.1097/YCT.0b013e3181e6317d
Original Study

Fractional Anisotropy Changes After Several Weeks of Daily Left High-Frequency Repetitive Transcranial Magnetic Stimulation of the Prefrontal Cortex to Treat Major Depression

Kozel, F. Andrew MD, MSCR*†‡; Johnson, Kevin A. PhD†‡; Nahas, Ziad MD, MSCR†‡; Nakonezny, Paul A. PhD§; Morgan, Paul S. PhD∥¶; Anderson, Berry S. PhD, RN†‡; Kose, Samet MD†‡; Li, Xingbao MD†‡; Lim, Kelvin O. MD#; Trivedi, Madhukar H. MD*; George, Mark S. MD†‡

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Objectives: As part of a sham controlled treatment trial using daily left repetitive transcranial magnetic stimulation (rTMS), brain changes associated with 4 to 6 weeks of treatment were examined using diffusion tensor imaging to noninvasively evaluate prefrontal white matter (WM) microstructure. A decrease in fractional anisotropy values of the left prefrontal WM could indicate damage to the region.

Methods: Diffusion tensor imaging was performed before and after 4 to 6 weeks of daily rTMS treatments. Mean fractional anisotropy levels associated with active rTMS and sham rTMS for the right and left prefrontal WM were assessed.

Results: Adequate images were acquired for 8 participants (active n = 4, sham n = 4) before and after rTMS. A mean increase was found for the left prefrontal WM. The mixed model revealed a trend toward a significant treatment group × region interaction effect (P = 0.11). Furthermore, simple region effects (left prefrontal WM vs right prefrontal WM) were at a trend toward significance for difference after treatment within the active rTMS group (P = 0.07), but not within the sham rTMS group (P = 0.88).

Conclusions: Repetitive transcranial magnetic stimulation resulted in no evidence of damage to WM on the side of stimulation. Diffusion tensor imaging may offer a unique modality to increase our understanding of mechanisms of action for rTMS.

© 2011 Lippincott Williams & Wilkins, Inc.


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