Cross-language interaction during sequential anomia treatment in three languages: Evidence from a trilingual person with aphasia

Abstract

Language rehabilitation research has reported mixed evidence in bilinguals with aphasia suggesting that therapy can benefit the treated language alone or additionally result in cross-language generalization to the untreated language, while cross-language interference effects are less common. However, treatment effects in multilinguals with aphasia (MWA) have been less frequently investigated, and examining cross-language interactions during therapy may help to better understand their treatment response in each language. This study reports on P1, a trilingual person with severe aphasia with extensive damage to cortical language regions and the basal ganglia, who received sequential semantic-based treatment for anomia in her L3 French, L1 Spanish and L2 English. Overall, significant treatment gains in the treated language were restricted to her L3 French, the weakest language, while her treatment response was limited across languages likely due to severe language impairment and extensive damage to the language processing network. Cross-language generalization effects were absent and P1 showed cross-language interference in her L2 English during treatment in her L3 French. Cross-language intrusions were observed between languages, more frequently in her L2 English (the least available language in treatment) than in her L1 Spanish (the strongest language). The absence of cross-language generalization and presence of cross-language interference in P1 were likely due to damage in the basal ganglia and executive deficits reflecting damage to the language control network. Severe language processing and language control impairments can hinder the balance between activation and inhibition mechanisms necessary to support response to language treatment in MWA.

Keywords: Anomia treatment; Basal ganglia; Cross-language generalization; Cross-language interference; Trilingual aphasia.

Figure 1.. Lesion location.

Axial CT (A) and sagittal MRI (B) brain scans showing P1’s extensive brain lesion in the left hemisphere including frontal, temporal and posterior parietal regions, as well as the external capsule and the basal ganglia. The CT scan is shown on radiological convention (left hemisphere is displayed on the right).

Figure 2.. Summary of assessment and treatment procedures.

P1 received anomia treatment delivered sequentially in her three languages (French treatment phase, Spanish treatment phase and English treatment phase). P1 completed 3 baseline, 12 treatment and 3 post-treatment naming probes (primary treatment outcomes) per language (colored dots: red = French, blue = Spanish, green = English). Post-treatment naming probes after French and Spanish treatment also served as baseline naming probes for the next treatment phase. P1 also completed baseline diagnostic assessments for language (Lang) and executive functions (EF), as well as verbal fluency tasks (VF) and the Boston Naming Test (BNT) (secondary outcome measures) after each treatment phase. Note that testing was discontinued after the final treatment phase due to acute health difficulties.

Figure 3.. Progression of naming accuracy during the French treatment phase.

Naming accuracy (language-dependent scoring method) trends for P1 across naming probes over the course of treatment (Time) during the French treatment phase contrasting treated items (red line) versus control items (blue line). 95% confidence intervals are shown as shaded regions around lines. Significant main effects of Time and Set demonstrated improvements on both types of items over the course of treatment in French, with higher accuracy noted for treated versus control items.

Figure 4.. Cross-language treatment effects on English untreated translations following the French treatment phase.

The significant Time x Set interaction on naming accuracy (language-dependent scoring method) for English translations during the French treatment phase is shown, contrasting untreated translation items (red line) versus control translation items (blue line). 95% confidence intervals are shown as shaded regions around lines. Naming accuracy remained unchanged for English untreated translations of French treated items (absence of cross-language generalization), while it decreased for English control translations (cross-language interference).

Figure 5:. Overall effects of the French treatment phase on naming accuracy.

The significant Time x Set interaction on naming accuracy (language-dependent scoring method) during the French treatment phase is shown contrasting target items (red line) and non-target items (blue line). 95% confidence intervals are shown as shaded regions around lines. While accuracy improved for target items over time, it decreased for non-target items.

Figure 6:. Dynamics of language selection for lexical retrieval during the French treatment phase.

The Time x Language interaction on naming accuracy (language-independent scoring method) during the French treatment phase is shown, contrasting the languages selected by P1 for lexical retrieval on naming probes: French (red), Spanish (green), and English (blue). 95% confidence intervals are shown as shaded regions around lines. During the French treatment phase, P1 showed superior naming accuracy in Spanish over English (main effect of retrieval language) with no notable differences between lexical retrieval in French versus Spanish. However, she shifted her retrieval language from Spanish to French as treatment in French progressed (Time x Spanish interaction) suggesting an increased selection of the treated language for lexical retrieval.

Figure 7.. Language selection for lexical retrieval during the French, Spanish and English treatment phases.

The Probe Language x Retrieval Language interaction on naming accuracy (language-independent scoring method) in each treatment phase is shown. The contrast between languages selected by P1 for lexical retrieval on naming probes is depicted (colored dots with error bars): French (red), Spanish (green), and English (blue). The French treatment phase (A) and the Spanish treatment phase (B) revealed that naming in French on French naming probes and naming in Spanish on Spanish naming probes yielded superior naming accuracy without significant cross-language intrusion from other languages, whereas naming probes in English showed cross-language intrusions from both French and Spanish. The English treatment phase (C) showed that selecting English and Spanish for lexical retrieval during English naming probes resulted in comparable levels of higher naming accuracy relative to naming in French (suggesting cross-language intrusion from the untreated Spanish into the treated English during naming probes). Selecting Spanish for lexical retrieval during Spanish naming probes showed superior accuracy compared to French and English, while no differences across languages were observed for naming probes in French (suggesting cross-language intrusion from both the treated English and the untreated Spanish into French during naming probes).