Cognate effects and cognitive control in patients with parallel and differential bilingual aphasia

The cognate facilitation effect on lexical access in bilingual aphasia: Evidence from the Boston Naming Test

Most cognate research suggests facilitation effects in picture naming, but how these effects manifest in bilinguals after brain damage remains unclear. Additionally, whether this effect is captured in clinical measures is largely unknown. Using data from the Boston Naming Test, we examined the naming of cognates and noncognates, the extent of cognate facilitation produced, and the individual differences in bilingual language experience associated with naming outcomes in forty Spanish-English bilingual persons with aphasia (BPWA) relative to thirty-one Spanish-English healthy bilinguals (HB). Results suggest that naming performance in L1 and L2 in both groups is modulated by lexical frequency, bilingual language experience, and by language impairment in BPWA. Although the two groups showed similarities, they deviated in benefit drawn from the extent of phoneme/grapheme overlap in cognate items. HB showed an association between cognate facilitation and bilingual language experience, while cognate facilitation in BPWA was only associated with L2 language impairment.

Speech fluency in bilinguals who stutter: Language proficiency and attentional demands as mediating factors

PURPOSE

The current study examines how speech disfluencies manifest themselves in the two languages of bilingual persons who stutter, starting from the hypothesis that stuttering is associated with an attentional deficit at the level of speech production.

METHODS

Twenty-eight bilingual people who stutter performed a spontaneous and a controlled speech production task, once in their dominant and once in their non-dominant language. The controlled production task (i.e. a network description task) was carried out once under a full-attention condition and once under a divided-attention condition where a non-linguistic, pitch discrimination task was performed simultaneously.

RESULTS

In both the spontaneous and the controlled speech task, bilingual persons who stutter produced more (typical and stuttering-like) disfluencies in their L2 than in their L1. Furthermore, whereas the typical disfluencies increased when attention was directed away from speech production, stuttering-like disfluencies decreased. This effect was however restricted to L2. In addition, L2 proficiency was generally found to be a predicting factor, with higher proficiency leading to fewer disfluencies.

CONCLUSIONS

These results suggest that speaking in a non-dominant language increases both typical and stuttering-like disfluencies in bilingual persons who stutter, but also that these two types of dysfluencies differ regarding their attentional origins. Our findings offer further support for attentional accounts of stuttering and have both theoretical and clinical implications.

The Protective Influence of Bilingualism on the Recovery of Phonological Input Processing in Aphasia After Stroke

Language-related potentials are increasingly used to objectify (mal)adaptive neuroplasticity in stroke-related aphasia recovery. Using preattentive [mismatch negativity (MMN)] and attentive (P300) phonologically related paradigms, neuroplasticity in sensory memory and cognitive functioning underlying phonological processing can be investigated. In aphasic patients, MMN amplitudes are generally reduced for speech sounds with a topographic source distribution in the right hemisphere. For P300 amplitudes and latencies, both normal and abnormal results have been reported. The current study investigates the preattentive and attentive phonological discrimination ability in 17 aphasic patients (6 monolinguals and 11 bilinguals, aged 41–71 years) at two timepoints during aphasia recovery. Between the two timepoints, a significant improvement of behavioral language performance in both languages is observed in all patients with the MMN latency at timepoint 1 as a predictive factor for aphasia recovery. In contrast to monolinguals, bilingual aphasic patients have a higher probability to improve their processing speed during rehabilitation, resulting in a shortening of the MMN latency over time, which sometimes progresses toward the normative values.