Transcranial magnetic stimulation and aphasia rehabilitation

Abstract

Repetitive transcranial magnetic stimulation (rTMS) has been reported to improve naming in chronic stroke patients with nonfluent aphasia since 2005. In part 1, we review the rationale for applying slow, 1-Hz, rTMS to the undamaged right hemisphere in chronic nonfluent aphasia patients after a left hemisphere stroke; and we present a transcranial magnetic stimulation (TMS) protocol used with these patients that is associated with long-term, improved naming post-TMS. In part 2, we present results from a case study with chronic nonfluent aphasia where TMS treatments were followed immediately by speech therapy (constraint-induced language therapy). In part 3, some possible mechanisms associated with improvement after a series of TMS treatments in stroke patients with aphasia are discussed.

Trial registration: ClinicalTrials.gov NCT00608582.

Figure 1

Legend box shows naming data for a single aphasia case, acquired immediately after suppression of 5 different RH cortical ROIs during exploratory Phase 1 TMS. Location of five frontal, RH ROIs are shown where each was suppressed in separate TMS sessions, with 1 Hz rTMS for 10 min. These five ROIs included R M1, mouth (orbicularis oris muscle, as verified with MEP), and four subregions within R Broca's area as defined in the text, using sulcal boundaries (arrows). A diagonal sulcus was present in the RH in this case. The PTr posterior ROI (green symbol), was the best-response ROI – i.e., the area associated with a naming score that reached at least 2 SD above baseline S&V naming ability (e.g., 15). During Phase 2 TMS, the PTr posterior ROI (green symbol) was used as the target for suppression with 1 Hz rTMS for ten, 20-min treatments in this case. Note that the number of pictures named correctly immediately post- rTMS decreased for any given ROI, as the distance from the best-response ROI increased by 1 or 2 cm, in an anterior or posterior direction. ROI, region of interest; PTr, pars triangularis; POp, pars opercularis; S&V, Snodgrass and Vanderwart. Reprinted with permission from Wolters Kluwer Health and authors' permission, Naeser, Martin, Lundgren, et al., Improved Language in a Chronic Nonfluent Aphasia Patient After Treatment with CPAP and TMS, J Cogn and Beh Neurol, 2009, 23(1), 29-38.

Figure 2

Significant improvement in Action naming test scores post- Intervention (TMS+CILT) for a severe nonfluent, global aphasia patient. Bargraph shows significant improvement (>2 SD) in BDAE verb Action Naming at 1 and 6 mo. post- TMS+CILT, compared to baseline testing pre- Intervention. Bargraph also displays previous scores, pre- and post- TMS alone, without CILT. Abbreviations: TMS = transcranial magnetic stimulation; CILT = constraint-induced language therapy; BDAE = Boston Diagnostic Aphasia Exam. Reprinted from Restorative Neurology and Neuroscience, 28(4), Naeser, Martin, Treglia et al., Research with rTMS in the treatment of aphasia, 511-529, Copyright (2010), with permission from IOS Press.

Figure 3

a and b: White matter pathways from horizontal, mid-portion of arcuate fasciculus (AF, green) connect primarily with pars opercularis (light blue), not posterior pars triangularis (yellow) or anterior pars triangularis (red), in the right hemisphere; a: axial view, and b: sagittal view. c: White matter pathways from horizontal, mid-portion of AF (orange) also connect with ventral premotor cortex (dark blue) in the right hemisphere; c: axial view. The R pars opercularis and the R ventral premotor cortical areas are regions that may be important for recovery of speech in chronic stroke patients with nonfluent aphasia. Pink area represents seed point in the horizontal, mid-portion of the AF in these DTI studies with normal controls.