Linguistic Approaches to Bilingualism - Volume 11, Issue 4, 2021

The present study investigated language inhibition and cross-language interference as two possible mechanisms of bilingual language control (BLC) that can be affected by Huntington’s disease (HD), a neurodegenerative disease (ND) affecting the striatum. To this aim, the study explored the performance of pre-symptomatic and early-stage HD patients in two experimental tasks meant to elicit cross-language interference and language inhibition, including a Stroop task and a language switching task. The results revealed dissociations between these two mechanisms, indicating that language activation or inhibition is related to HD pathology while cross-language interference is not. Switch costs in HD patients were greater than controls in low-demand control conditions of language switching (longer preparation time), while Stroop effects were similar between the two groups of participants. This result was interpreted as a difficulty in overcoming the excessive inhibition applied to non-target language. The BLC processes related to the striatum and subcortical structures are discussed.

Evaluation of the cognitive level of older adults, including decisions about meeting clinical thresholds for dementia, is typically based on behavioral levels of performance. However, individuals with high cognitive reserve will outperform the levels typically associated with their brain structure, providing inaccurate assessments of their status. We define cognitive reserve as the relation between brain integrity and cognitive level, and use the case of bilingualism as a source of cognitive reserve to illustrate how information from only one can distort the interpretation of the individual’s cognitive status.

Whether bilingualism acts positively against neurocognitive decline is intensely debated. Although some reasons for it might be ideological, variability in sampling procedures and experimental design represent potential sources of inconsistency among studies. In this paper, we contend that bilingualism renders the extra-years of life of an increasingly long-lived population cognitively healthy, but only under specific conditions such as continuous practice and immersion in bilingual environments. We thus disagree with some authors’ recommendation that bilingualism be removed from consideration as a neuroprotective factor. We suggest, at the same time, that bilingualism should not be treated as axiologically superior to other environmental measures that promise to contrast the progressive loss of functional independence with increasing age. We conclude by emphasizing the need to evaluate the protective effects of L2-learning on the aging brain in a multimodal intervention perspective, thereby dissociating the effects of bilingualism from those of other cognitively stimulating factors.

Bilingualism has been associated with age-related cognitive advantage. It is important to study cognitive control mechanisms to better understand this phenomenon. We sought to examine proactive and reactive control, as measured by fast and slow responses, respectively. The neural underpinnings of these modes of control were studied in rigorously matched elderly monolinguals and bilinguals, using fMRI performance on a Simon task. The results indicate that bilinguals performed efficiently in proactive mode, as more activation and connectivity were observed in the monolinguals. On the other hand, the monolinguals functioned more efficiently in reactive mode, recruiting fewer brain areas than the bilinguals. These results suggest that bilinguals’ function effortlessly and economically in proactive mode, which is preserved through lifelong use of languages, whereas monolinguals are efficient in reactive mode, which they use more often as a consequence of aging. Thus, frequent use in daily life contributes to efficient functioning in the respective mode of control.

It has been suggested that bilingualism is beneficial for executive control and could have positive long-term effects by delaying the onset of symptoms of degenerative diseases. This research investigates, for the first time, the impact of bilingualism on executive control (monitoring and inhibitory control) in individuals with Multiple Sclerosis (MS), a neurodegenerative disease which commonly causes deficiencies in the cognitive system. Bilingual and monolingual adults, with and without an MS diagnosis, performed a flanker task with two degrees of monitoring demands (high monitoring vs. low monitoring). Results showed that bilingual MS patients had inhibitory control and monitoring abilities that were similar to healthy bilingual controls. In contrast, monolingual MS patients showed similar inhibitory control but significantly worse monitoring abilities compared to monolingual healthy controls. We propose that the similar behaviour between bilingual groups suggests that bilingualism might counteract cognitive deficits related to MS, especially with respect to monitoring. The high monitoring cost observed in monolingual patients seems related to underlying deficits in monitoring and possibly switching, executive control abilities commonly impaired in MS patients from early stages. Our findings provide some preliminary evidence for the cognitive reserve hypothesis in bilingual MS patients.

We investigated whether bilingual older adults experience within- and cross-language competition during spoken word recognition similarly to younger adults matched on age of second language (L2) acquisition, objective and subjective L2 proficiency, and current L2 exposure. In a visual world eye-tracking paradigm, older and younger adults, who were French-dominant or English-dominant English-French bilinguals, listened to English words, and looked at pictures including the target (field), a within-language competitor (feet) or cross-language (French) competitor (fille, “girl”), and unrelated filler pictures while their eye movements were monitored. Older adults showed evidence of greater within-language competition as a function of increased target and competitor phonological overlap. There was some evidence of age-related differences in cross-language competition, however, it was quite small overall and varied as a function of target language proficiency. These results suggest that greater within- and possibly cross-language lexical competition during spoken word recognition may underlie some of the communication difficulties encountered by healthy bilingual older adults.