Improvement of language functions in a chronic non-fluent post-stroke aphasic patient following bilateral sequential theta burst magnetic stimulation

Abstract

In chronic non-fluent aphasia patients, inhibition of the intact right hemisphere (RH), by transcranial magnetic stimulation (TMS) or similar methods, can induce improvement in language functions. The supposed mechanism behind this improvement is a release of preserved left hemisphere (LH) language networks from RH transcallosal inhibition. Direct stimulation of the damaged LH can sometimes bring similar results too. Therefore, we developed a novel treatment approach that combined direct LH (Broca's area (BA)) stimulation, by intermittent theta burst stimulation (TBS), with homologue RH area's inhibition, by continuous TBS. We present the results of application of 15 daily sessions of the described treatment approach in a right-handed patient with chronic post-stroke non-fluent aphasia. The intervention appeared to improve several language functions, but most notably propositional speech, semantic fluency, short-term verbal memory, and verbal learning. Bilateral TBS modulation of activation of the language-related areas of both hemispheres seems to be a feasible and promising way to induce recovery in chronic aphasic patients. Due to potentially cumulative physiological effects of bilateral stimulation, the improvements may be even greater than following unilateral interventions.

Network Controllability in the Inferior Frontal Gyrus Relates to Controlled Language Variability and Susceptibility to TMS

“…This effect is ameliorated with inhibition of the LIFG, potentially because TMS may partially suppress the LIFG's role in higher processing demands (Nicolo et al, 2016, Vuksanović et al, 2015 due to an increased number of connections within the network (i.e., lower modal controllability associated with denser connections). During the closed task, blunted practice effects in individuals with higher modal controllability can be improved with cTBS.…”

Non-invasive Brain Stimulation in the Treatment of Post-stroke and Neurodegenerative Aphasia: Parallels, Differences, and Lessons Learned

“… (A) Sites and mechanism of stimulation for TMS post-stroke aphasia (Garcia et al, 2013; Vuksanović et al, 2015). (B) Sites and mechanism of stimulation for tDCS post-stroke aphasia.…”

The Effect of Noninvasive Brain Stimulation on Poststroke Cognitive Function: A Systematic Review

“…After bilateral TBS over Broca's area and the contralesional homologue (cTBS contralesional, iTBS ipsilesional), apart from language improvements, short-term verbal memory and verbal learning improved, as reflected by scores on immediate and delayed recall conditions on the Rey Auditory Verbal Learning Test (improved by 100% compared to baseline). 53 tDCS Studies. A crossover study by Kazuta et al 54 with a low risk of bias included 12 patients with auditory verbal memory deficits (3-12 months poststroke).…”

“…After 10 sessions, a treatment effect was found for iTBS on semantic fluency. 56 Vuksanović et al 53 reported on a single case of a chronic aphasia patient, in which iTBS stimulation was applied over the lesioned Broca's area and cTBS stimulation over the contralateral homologue area, and found increased performance on the semantic verbal fluency task, especially at T2. 53 Both studies had a low risk of bias.…”