Research with transcranial magnetic stimulation in the treatment of aphasia

Abstract

Repetitive transcranial magnetic stimulation (rTMS) has been used to improve language behavior, including naming, in stroke patients with chronic, nonfluent aphasia. Part 1 of this article reviews functional imaging studies related to language recovery in aphasia. Part 2 reviews the rationale for using rTMS to treat nonfluent aphasia (based on functional imaging) and presents our current rTMS protocol. We present language results from our rTMS studies as well as imaging results from overt naming functional MRI scans obtained before and after a series of rTMS treatments. Part 3 presents results from a pilot study in which rTMS treatments were followed immediately by constraint-induced language therapy. Part 4 reviews our diffusion tensor imaging study examining the possible connectivity of the arcuate fasciculus to different parts of Broca's area (pars triangularis, pars opercularis) and to the ventral premotor cortex. The potential role of mirror neurons in the right pars opercularis and ventral premotor cortex in aphasia recovery is discussed.

Figures

Figure 1

RH cortical ROIs examined during Phase 1 rTMS treatment protocol including M1, mouth (orbicularis oris, verified with motor evoked potential), superior temporal gyrus (STG) and subregions within Broca’s area: PTr posterior, and POp. Phase 1 establishes the location of the Best RH Cortical ROI to Suppress during Phase 2, treatment.

Figure 2

Overt naming fMRI results for ROI analysis pre- and post-Phase 2 rTMS for P1, good responder. Results shown for scans pre-TMS, 3 mo. post-TMS, 16 mo. post-TMS, and 46 mo. post-TMS. Bar graph displays the mean effect size for the L and R SMA activation. There was a significant shift to greater L SMA activation at 16 mo. post-TMS compared to pre-TMS and to 3 mo. post-TMS. Greater L SMA activation still remained at 46 mo. post-TMS.