Language specificity of lexical-phonological therapy in bilingual aphasia: A clinical and electrophysiological study

Abstract

Based on findings for overlapping representations of bilingual people's first (L1) and second (L2) languages, unilingual therapies of bilingual aphasia have been proposed to benefit the untrained language. However, the generalisation patterns of intra-and cross-language and phonological therapy and their neural bases remain unclear. We tested whether the effects of an intensive lexical-phonological training (LPT) in L2 transferred to L1 word production in a Persian-French bilingual stroke patient with Broca's aphasia. Language performance was assessed using the Bilingual Aphasia Test, a 144-item picture naming (PN) task and a word -picture verification (WPV) task. Electroencephalography (EEG) was recorded during PN and WPV in both languages before and after an LPT in French on a wordlist from the PN task. After the therapy, naming improved only for the treated L2 items. The naming performance improved neither in the untrained L2 items nor in the corresponding items in L1. EEG analyses revealed a Language x Session topographic interaction at 540 ms post-stimulus, driven by a modification of the electrophysiological response to the treated L2 but not L1 items. These results indicate that LPT modified the brain networks engaged in the phonological-phonetic processing during naming only in the trained language for the trained items.

Second-language proficiency modulates the brain language control network in bilingual translators: an event-related fMRI study

“…A related issue is the possible effect of the “linguistic distance” between each of the L1-L2 pairs studied here on the engagement of the language control system, a topic that has to date been scarcely studied. A recent clinical observation might support the fact that the distance between languages may influence language control (Radman, Spierer, Laganaro, Annoni & Colombo, 2016); however, these data have been obtained with very distant language pairs (Persian–French) and not with nearer European languages. Moreover, it is of interest that despite the absence of differences between the groups at the behavioural level (performance and reaction time), the functional analysis was still able to show that activation patterns were influenced by the difference in proficiency between groups, and by their ability to retrieve lexical information and manage the use of their two languages.…”

Alterations to dual stream connectivity predicts response to aphasia therapy following stroke

“…Laganaro et al 45 reported that ERPs in four patients with aphasia were normalised for processes that were unimpaired following aphasia therapy, while Pulvermuller et al 46 showed increased negativity around 250 to 300ms for words post-treatment, however, no change was observed for pseudowords. Radman et al 47 showed that lexical-phonological therapy in a participant with chronic bilingual aphasia modified EEG responses to treated but not untreated words consistent with modulation of brain networks involved in phoneticphonological processing. While these studies did not examine whether EEG predicted aphasia treatment response they do support the current finding that therapy success and potential for recovery involves engagement of normal left-hemisphere language networks.…”

Embodied Semantics in a Second Language: Critical Review and Clinical Implications

“…In fact, bilingual rehabilitation, the cross language transfer (CLT) of treatment benefits from one language to the other(s) is a notable topic. It is not yet clear which factors influence the success of CLT in bilingual aphasics: premorbid language proficiency, degree and type of language impairments or various forms of therapy (Miertsch et al, 2009; Faroqi-Shah et al, 2010; Kiran and Iakupova, 2011; Kiran et al, 2013; Ansaldo and Saidi, 2014; Radman et al, 2016). Moreover, if the transfer does not take place, the selective recovery of one language could be seen as partial evidence of a different neural representation of the two languages.…”