Fractional anisotropy changes after several weeks of daily left high-frequency repetitive transcranial magnetic stimulation of the prefrontal cortex to treat major depression

J ECT. 2011 Mar;27(1):5-10. doi: 10.1097/YCT.0b013e3181e6317d.

Abstract

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.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anisotropy
  • Depressive Disorder, Major / therapy*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prefrontal Cortex*
  • Transcranial Magnetic Stimulation*