Transcranial brain stimulation (TMS and tDCS) for post-stroke aphasia rehabilitation: Controversies.

Lucia Iracema Zanotto De Mendonça

doi:10.1590/s1980-57642014dn83000003

Abstract

Transcranial brain stimulation (TS) techniques have been investigated for use in the rehabilitation of post-stroke aphasia. According to previous reports, functional recovery by the left hemisphere improves recovery from aphasia, when compared with right hemisphere participation. TS has been applied to stimulate the activity of the left hemisphere or to inhibit homotopic areas in the right hemisphere. Various factors can interfere with the brain's response to TS, including the size and location of the lesion, the time elapsed since the causal event, and individual differences in the hemispheric language dominance pattern. The following questions are discussed in the present article:[a] Is inhibition of the right hemisphere truly beneficial?;[b] Is the transference of the language network to the left hemisphere truly desirable in all patients?;[c] Is the use of TS during the post-stroke subacute phase truly appropriate? Different patterns of neuroplasticity must occur in post-stroke aphasia.

Highlights

Aphasia is a significant sequela of neurological diseases, especially stroke, and recovery differs between patients.In healthy individuals, language is a complex function that includes the participation of multiple brain areas from both hemispheres
transcranial magnetic stimulation (TMS) applied over the anterior inferior frontal gyrus (IFG) (PTr) significantly slowed subjects’ reactions for the semantic tasks,[40] while TMS of posterior IFG (POp) impaired reaction times and accuracy of phonological decision tasks.[38]
Bilateral POp is related with phonologic processing and left pars triangularis (PTr) is related with semantic processing

Summary

Introduction

Language is a complex function that includes the participation of multiple brain areas from both hemispheres For this reason, language is vulnerable to brain injury. The left hemisphere shows dominance in linguistic skills for 96% of healthy, right-handed individuals.[1] human communication is based on a set of phonological, semantic, discursive and pragmatic features, which depend on the integration between left and right hemispheres and interaction with other cognitive functions. These data suggest that the right hemisphere plays a specific role in language. Functional neuroimaging has detected changes in the pattern of brain activation in bi/multilingualism[3,4] and as a function of age.[5,6] the brain circuits associated with language vary based on the life experiences of an individual, and this individualization may influence the reorganization of the neural network that occurs after brain injury

Objectives

Results

Conclusion