The purpose of this research is to investigate whether repetitive transcranial magnetic stimulation (rTMS) can be used to improve speech in chronic stroke patients with nonfluent aphasia. rTMS allows non-invasive stimulation of human cortex. Slow (1 Hz) rTMS appears to decrease excitability in the targeted cortical region of interest (ROI) leading to measurable behavioral effects. A small 8-shaped coil (as will be used in the present study) affects primarily a cortical area of less than 2 x 2 cm. We have observed in fMRI studies that patients with nonfluent speech (slow, hesitant, poorly articulated, agranunatic speech) have excess blood flow (presumed abnormal increase in cortical excitability) in many right (R) perisylvian areas including R sensorimotor mouth, R Broca's homologue (BA 45) and R Wernicke's homologue(BA 22). Slow (1 Hz) rTMS will be used to suppress activation of specific ROls observed to have high blood flow (presumed overactivation) on fMRI. It is expected that suppression of activity in the directly targeted ROl will have an overall modulating effect on functionally connected elements of the distributed neural network for naming (and propositional speech) in chronic stroke patients with nonfluent aphasia, and will result in a behavioral improvement. Pilot data on four nonfluent aphasia patients support this claim and document the feasibility and safety of the study. Naming Ability (20 pictures of common objects) and reaction times are measured immediately pre- and immediately post- an rTMS treatment. There are two phases. Phase 1 includes aphasia patients (n=40) and age-matched normal controls (n=12). For normal controls, Phase 1 will provide information on the effect of slow rTMS on 7 language-related ROIs. For aphasia patients, Phase 1 will provide information regarding which of 5 ROIs is the most promising for more extensive rTMS treatment in Phase 2. Phase 2 (aphasia patients only) is a randomized, sham-controlled, incomplete crossover design. One group (n=20) receives 10 Real rTMS treatments over a two-week period; and one group (n=20), 10 Sham rTMS treatments over a two-week period. Only those who receive Sham treatments FIRST will be crossed over. It is hypothesized that 10 sessions of Real rTMS at 1 Hz given over a two week period to a specific ROl (e.g., R BA 45, supported from our pilot data) will significantly improve picture naming and propositional speech, when tested at 1-2 weeks and 2 months post- the last rTMS treatment, as compared to pre- Phase 2 testing. Sham rTMS to the same ROl is hypothesized to have no effect. This will be the first systematic rTMS study designed to improve speech in stroke patients with nonfluent aphasia. The implications could be far reaching regarding optimal treatment in aphasia with potential for combining current language therapies with rTMS to promote maximum recovery of language.
Showing the most recent 10 out of 38 publications
