Differential approach to stroke aphasia and primary progressive aphasia using transcranial magnetic stimulation: A systematic review

Language disorders can occur as a consequence of stroke or neurodegenerative disorders, among other causes. Post-stroke aphasia (PSA) and primary progressive aphasia (PPA) are syndromes that, despite having common features, differ in the brain mechanisms that cause their symptoms. These differences in the underlying functional neuroanatomical changes may influence the way they are addressed by different non-invasive brain stimulation techniques and, in particular, by repetitive transcranial magnetic stimulation (rTMS). The aim of this systematic review is to evaluate the efficacy of rTMS in the treatment of PSA and PPA, as well as the differences in the approach to these disorders using rTMS. To this end, a total of 36 articles were found in the Web of Science, Scopus, and PubMed. The results obtained suggest that whereas in PSA, the selection of the stimulation paradigm is based on bi-hemispheric functional reorganisation models with a tendency towards the application of inhibitory rTMS in the contralateral right hemisphere, in PPA, the application of excitatory rTMS in functionally compromised areas seems to show promising changes. It is concluded that rTMS is a potential treatment in the therapy of both disorders, although differences in the underlying brain mechanisms differentiate the rTMS approach in each case.