Stimulating conversation: enhancement of elicited propositional speech in a patient with chronic non-fluent aphasia following transcranial magnetic stimulation

Abstract

Although evidence suggests that patients with left hemisphere strokes and non-fluent aphasia who receive 1Hz repetitive transcranial magnetic stimulation (rTMS) over the intact right inferior frontal gyrus experience persistent benefits in naming, it remains unclear whether the effects of rTMS in these patients generalize to other language abilities. We report a subject with chronic non-fluent aphasia who showed stable deficits of elicited propositional speech over the course of 5 years, and received 1200 pulses of 1Hz rTMS daily for 10 days at a site identified as being optimally responsive to rTMS in this patient. Consistent with prior studies there was improvement in object naming, with a statistically significant improvement in action naming. Improvement was also demonstrated in picture description at 2, 6, and 10 months after rTMS with respect to the number of narrative words and nouns, sentence length, and use of closed class words. Compared to his baseline performance, the patient showed significant improvement on the Western Aphasia Battery (WAB) subscale for spontaneous speech. These findings suggest that manipulation of the intact contralesional cortex in patients with non-fluent aphasia may result in language benefits that generalize beyond naming to include other aspects of language production.

Figures

Figure 1

a) The six sites at which TMS was delivered in Phase 1 of the study: M1 corresponding to the mouth (blue), Brodmann area 44 (BA 44; green), dorsal posterior BA 45 (red), dorsal anterior BA 44/ventral posterior BA 45 (yellow), dorsal anterior BA 45 (purple), and BA 47 (brown). Figure 1b) The difference in performance on a naming task before and after rTMS to the six right hemisphere sites. Hatched lines indicate significant differences.

Figure 2

Performance on measured of propositional speech and naming. 2a) The Western Aphasia Battery spontaneous speech subscale. Black bars indicate the Information Content component of the Spontaneous Speech subscale; grey bars indicate the Fluency component. 2b-2e) Performance on the Cookie Theft Picture Description: b) total number of narrative words used, c) number of different nouns used, d) mean sentence length, and e) number of closed class words used per sentence. Vertical bars represent standard error. 2f) Performance on the Naming in Categories subtest of the BDAE. Improvement in action naming between baseline and six months is significant (asterisk).

Figure 3

T1-weighted MRI (1mm slice images with field of view 192 × 256 × 80; axial images depicted are—from inferior to superior—slices 124, 100, 90, 84, 78, and 66). Extensive cortical lesion is present in middle and inferior frontal gyrus areas (includes Broca’s area), and in most of the middle and superior temporal gyrus areas (includes Wernicke’s area). There is some sparing of deep white matter, adjacent to inferior frontal horn (arrows, medial subcallosal fasciculus), deep to Broca’s area. Extensive sensorimotor cortex and parietal lobe lesion is present, with sparing of parts of BA 37 and 39 (angular gyrus).