Research with rTMS in the treatment of aphasia

Abstract

This review of our research with rTMS to treat aphasia contains four parts: Part 1 reviews functional brain imaging studies related to recovery of language in aphasia with emphasis on nonfluent aphasia. Part 2 presents the rationale for using rTMS to treat nonfluent aphasia patients (based on results from functional imaging studies). Part 2 also reviews our current rTMS treatment protocol used with nonfluent aphasia patients, and our functional imaging results from overt naming fMRI scans, obtained pre- and post- a series of rTMS treatments. Part 3 presents results from a pilot study where rTMS treatments were followed immediately by constraint-induced language therapy (CILT). Part 4 reviews our diffusion tensor imaging (DTI) study that examined white matter connections between the horizontal, midportion of the arcuate fasciculus (hAF) to different parts within Broca's area (pars triangularis, PTr; pars opercularis, POp), and the ventral premotor cortex (vPMC) in the RH and in the LH. Part 4 also addresses some of the possible mechanisms involved with improved naming and speech, following rTMS with nonfluent aphasia patients.

Figures

Fig. 1

Schematic diagram showing the location of four RH cortical ROIs that were suppressed with 10 mins rTMS in separate sessions (Phase 1), to find the ‘best response’ cortical ROI for each patient. Abbreviations: rTMS = repetitive Transcranial Magnetic Stimulation; ROI = Region of Interest.

Fig. 2

Graphs showing naming scores on three standardized naming tests administered pre- rTMS, and at 2 weeks, 2 months and 8 months after 10 rTMS treatments. Reprinted with author’s permission and Brain and Language (Naeser et al., 2005a).

Fig. 3

Overt naming fMRI results for ROI analyses, pre- and post- Phase 2 rTMS for P1, good responder. Bargraph displays the mean effect size for the L and R SMA activation for fMRI scans pre-TMS and 3, 16, and 46 mo. post-TMS. 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 remained at 46 mo. post-TMS, relative to pre-TMS and 3 mo. post-TMS. Abbreviations: fMRI = functional Magnetic Resonance Imaging; rTMS = repetitive Transcranial Magnetic Stimulation; SMA = Supplementary Motor Area. Reprinted with authors’ and Brain and Language (Martin et al., 2009).

Fig. 4

Significant improvement in Action naming test scores post- Intervention (TMS plus CILT) for a severe nonfluent, global aphasia patient. a) Time Series graph shows significant increase in pictures named over time (pre- Intervention, during Daily Intervention and post- Intervention; p=.035); b) Bargraph shows significant improvement (>2 SD) in BDAE Action Naming at 1 and 6 mo. post- Intervention, compared to Baseline testing pre- Intervention. Bargraph also displays scores pre- and post-TMS alone, without speech therapy. Abbreviations: TMS = transcranial magnetic stimulation; CILT = constraint-induced language therapy; BDAE = Boston Diagnostic Aphasia Exam.

Fig. 5

Significant improvement in Boston Naming Test (BNT) scores post- Intervention (TMS plus CILT) for a mild nonfluent aphasia patient. Bargraph shows significant improvement (>2 SD) at 2 mo. post- Intervention, compared to Baseline testing pre- Intervention. Bargraph also displays previous BNT scores pre- and post-TMS treatment alone (without speech therapy); and pre- and post- CPAP scores. Abbreviations: TMS = transcranial magnetic stimulation; CILT = constraint-induced language therapy; CPAP = Continuous Positive Airway Pressure.

Fig. 6

a) Schematic diagram showing U-fibers, short association fibers (blue arrow) (Schmahmann and Pandya, 2006). Reprinted with permission from Oxford University Press. b) DTI tractography showing U-fibers (dark blue) between R PTr and R POp in two normal controls.